Uso de aguas residuales provenientes de una planta productora de
Transcription
Uso de aguas residuales provenientes de una planta productora de
The effects of using shrimp meal in broiler diets on live performance and carcass traits Lourdes I. Maldonado and Héctor Santiago Department of Animal Industry, University of Puerto Rico at Mayagüez Abstract An experiment was conducted to evaluate the effect of the inclusion of different levels of shrimp meal (SM) in diets on growth performance and carcass traits of broilers. A total of 160 d-old chicks were randomized in four treatments with four replicate pens of 10 birds each. Treatments consisted of SM inclusion at 0 (Control), 3, 6, and 9% in both starter (0-21 d) and grower (22 - 49 d) diets. Birds were raised under standard commercial conditions and provided with feed and water ad-libitum. Feed and birds were weighed weekly up to 49 d to determine bodyweight (BW), feed intake (FI), and feed conversion (FC). There was a negative linear response (P < .05) in BW with increasing levels of SM in the diet until 35 d of age. BW decreased as the dietary percentage of SM increased. At all ages, control birds were heavier (P<.05) than those fed 9% SM, while BW of those receiving 3 and 6% SM did not differ from the other treatments. During the starter period FC was similar for all treatments averaging 2.16 g feed/ g BW. However, at 49 d control (2.44) and 3% SM fed birds (2.71) had lower (P < .05) FC than those fed 9% SM (4.50), while FC of birds fed 6% SM (3.30) did not differ from the other treatments. No differences in FI were observed among treatments. Final live bodyweight (LBW) and plucked carcass weight (PCW) of processed birds were similar for the control, 3 and 6% SM treatments but higher than those of the 9% SM diet. Dressed carcass weight (DCW) of control birds was heavier than those of birds fed 6 and 9 but not 3% SM. No differences in plucked carcass yield were observed among treatments. However, control birds exhibited higher dressed carcass yield than those of the 6 and 9% SM birds. No differences in yields of abdominal fat, back, neck, wing, and drumstick were observed among treatments. The thigh and breast yields of control, 3 and 6% fed birds were similar but higher than those exhibited by the 9% SM birds. The present results indicate that SM could be a potential feed ingredient to supply part of the dietary protein requirements of broilers but its inclusion should be limited to between 3 and 6% of the diet to sustain adequate growth performance and carcass traits. Resumen Se realizó un experimento con el objetivo de evaluar el efecto de la inclusión de harina de camarón (HC) a 0, 3, 6, y 9% en la dieta sobre el desempeño productivo de pollos parrilleros. Un total de 160 pollos se distribuyeron aleatoriamente en cuatro tratamientos y 4 réplicas (10 aves por jaula). Dietas de dos etapas fueron evaluadas, iniciadora ( 0 – 21 d) y de crecimiento (22 – 49 d ). Las aves se criaron bajo las condiciones estádares comerciales y se les proveyó agua y alimento ad-libitum. El alimento y las aves se pesaron a los 7, 14, 21, 28, 35, 42 y 49 días para determinar el peso vivo (PV), consumo (C), la conversión de alimento (CA) y el rendimiento de la canal. El peso vivo disminuyó (P < .05) con el aumento en los niveles de inclusión de HC. No hubo diferencias (P < .05) en C, pero la CA los del tratamiento con 0 y 3% CA fue menor ( P < .05) a tratamientos con 9%. El PV y el peso de la canal fue similar para 0, 3 y 6%, pero mayor (P < .05) a los pollos con 9% (HC). No hubo diferencias (P < .05) en el rendimiento de la grasa abdominal, torso, cuello, ala y muslo entre tratamientos. El rendimiento de la cadera y pechuga fueron similares entre los tratamientos 0, 3 y 6% pero mayores que en el tratamiento de 9%. Los resultados de este estudio indica que la HC puede ser un ingrediente potencial para suplir parte de la proteína requerida por los pollos parrilleros, pero sus niveles de inclusión deben limitarce a 3 y 6%. 1 Introduction The broiler industry is the second largest agricultural sector of Puerto Rico. Broiler production costs here are higher than in other countries due to the fact that there is no local production of grains and most feed ingredients used in poultry diets are imported. Therefore, to reduce feed costs it is crucial to find novel feedstuffs that are feasible, available, economical, and of adequate nutritional value, that can substitute for at least part of the imported ingredients conventionally used in broiler diets. A local aquaculture company produces annually some 1,800 tons of salt water shrimp. Since the heads comprise about 44% of whole raw shrimp (Meyers and Rutledge, 1971) we estimate that this company alone generates on the order of 800 tons of waste that is sent to land fills for disposal. Shrimp meal (SM), the dried waste of the shrimp industry, is comprised of heads, hulls, shrimp not suitable for market, and fish accidentally caught with shrimp during harvest. SM contains approximately 50% crude protein on a dry matter basis (Rosenfeld et al., 1997 and Gernat, 2001) and could be a valuable feed ingredient to partially or totally replace soybean meal in broiler diets. Shrimp meal has been used successfully as a feed ingredient in diets of laying hens (Rosenfeld et al., 1997) and broilers (Singletary et al, 1935; Ewing, 1963; Damron et al., 1964; Ilian et al., 1985, and Islam et al., 1994; Gernat, 2001). In these studies the use of shrimp meal in broiler diets had no detrimental effect on performance and organoleptic properties of breast meat. However, no studies could be found evaluating the effects of the use of shrimp meal on other carcass traits. Materials and Methods Shrimp wastes were collected from the processing facilities of Eureka Marine Products in Dorado. Wastes were transferred to an 8’ x 8’ air steam dryer and dried at 65° C for 72 h. The dried wastes were grounded to a particle size of 1.0 mm. A proximate analysis and amino acid profile were performed on the final product prior to diet formulation according to methods of AOAC (1990). A two phase feeding regime consisting of starter (0 to 21 d) and grower (22 to 49 d) was used in the experiment. Diets were corn and soybean meal based and formulated to meet or exceed the NRC recommendation for broilers (NRC, 1994). The treatments consisted on inclusion of SM at 0 (control), 3, 6, and 9% of the diet to partially substitute the crude protein contributed by soybean meal. 2 A total of 160 broiler chicks were raised under standard commercial conditions in an open-sided poultry house at the Small Animal Research Farm in Lajas of the Department of Animal Industry. Birds were randomly assigned to 16 floor pens with four replicate pens per treatment. Chicks were raised under a 24 h of light photo regimen and provided with sufficient feed and water for ad-libitum consumption. Birds and feed were weighed at 7, 14, 21, 28, 35, 42, and 49 d of age to determine bodyweight (BW), feed intake (FI), and feed conversion (FC). At 49 d, four birds per replicate pen for a total of 16 per treatment were randomly selected, wing banded and kept 12 h prior to slaughter without access to feed. After feed withdrawal birds were weighed, exanguinated, scalded, mechanically plucked, and manually eviscerated. Carcasses were chilled overnight in an ice-slush tank maintained at 0 °C. After chilling, carcasses were drained, reweighed, and cut into the following portions: wings, drumsticks, thighs, breast with ribs, back, and neck. Carcass parts and abdominal fats were weighted and the yield expressed as percentage of live bodyweight (LBW). Data were analyzed according to a Completely Randomized design by ANOVA using the GLM procedures of SAS® (SAS Institute, 1990). The Tukey multiple comparison test was used to separate treatment means. All statements of significance are based on a probability of P< 0.05. Results and Discussion As shown in Table 1, growth performance of control birds was superior to that of those fed 9% SM diets. At all ages, control birds were significantly heavier than those fed 9% SM, while BW of those receiving 3 and 6% SM were intermediate; 3 % SM differed from the control at 7 d and again at 35 d, while at 42 d both 3 and 6% SM were superior to 9% SM. There was a significant negative linear response in BW with increasing levels of SM in the diet at all ages. BW decreased as the percentage of SM increased in the diet. No significant differences in FI were observed in either the starter or grower periods (Table 1). During the starter period FC was similar for all treatments averaging 2.16 overall and ranging from 1.94 to 2.33 (g feed/ g BW). At 49 d, control (2.44) and birds fed 3% SM (2.71) had significantly lower FC than those fed 9% SM (4.50), while FC of birds fed 6% SM (3.30) did not differ from the other treatments. Cunha et al. (2003a) found that 0, 3, 9 and 12% of SM inclusion in broiler diets resulted in no significant differences in FI or FC. Thus there is agreement with results of the present study in FI, but disagreement in the effects of higher levels of SM inclusion on FC. Those researchers 3 observed a quadratic effect between BW and SM level wherein the best levels of inclusion were 5.46, 5.87, and 6.16%. Table 1. The effect of SM included at different levels in broiler diets on body weight and feed conversion 0% SM 3% SM 6% SM 9% SM Age (d) Body weight (g) 1 42a 42a 42a 42a a ab b 131 125 125b 7 139 a ab ab 285 296 261b 14 320 a ab ab 479 459 430b 21 527 a ab ab 852 840 761b 28 959 a ab b 1,305 1,261 1,061c 35 1,428 a a a 1,739 1,669 1,400b 42 1,860 a ab ab 2,242 2,241 1,941b 49 2,365 Feed Convertion (g feed / g body weight) Starter (1 – 21 d) 1.94a Grower (22 – 49 d) 2.44a a-b 2.16a 2.71a 2.33a 3.30ab 2.20a 4.50b Means in a given row bearing different superscripts differ significantly at P < 0.05. The LBW and plucked carcass weight (PCW) of processed birds were similar for control, 3 and 6%, but significantly higher than for those fed 9% SM (Table 2). Control dressed carcass weight (DCW) was significantly heavier than those of birds fed 6 and 9% SM. LBW, PCW, and DCW tended to decrease as the percentage inclusion of SM increased in the diet. No differences in plucked carcass yield were observed among treatments, values ranging from 88.7 to 89.7 %. However, a higher dressed carcass yield was observed for the control birds than for those of 6 and 9% SM. As shown in Table 3, no significant differences in yields of abdominal fat, back, neck, wing, and drumsticks were observed among treatments. The breast yield of control, 3% and 6% fed birds were similar but significantly higher than that of 9% SM birds. The same was true of thigh yield except that the difference between the control and 9% SM was not significant. In a similar experiment, Cunha et al. (2003b) reported no significant differences in breast, thigh, and drumstick yields of broilers feed 0, 3, 6, 9 and 12% SM. Conclusion The results of this study indicate that SM shows promise as a potential feed ingredient to supply part of the dietary protein requirements of broilers, but its inclusion should be limited to between 3 and 6% of the diet in order not to sacrifice growth performance and desirable carcass traits. 4 Table 2. The effect of SM included at different levels in broiler diets on live body weight, lucked weight, hot dressed weight, cold dressed weight and percentage plucked, hot and cold dressed yield 1, 2. 0% SM 3% SM 6% SM 9% SM Trait Live body weight3 (g) 2,548a 2,365a 2,319a 1,884b Plucked weight4 (g) 2,285a 2,179a 2,063a 1,683b Hot dressed weight5 (g) 1,771a 1,639ab 1,546b 1,236c Cold dressed weight6 (g) 1,887a 1,747ab 1,649b 1,331c 89.7 89.5 88.8 88.7 Plucked carcass yield (%)7 a Hot dressed yield (%) 69.5 67.1 66.5 64.9b Cold dressed yield9 (%) 74.0a 71.6ab 70.9b 70.2b 8 ab ab a-b Means in a given row bearing different superscripts differ significantly at P < 0.05. Values given in this table correspond to least-squares means obtained from ANOVA and their pooled SEM. 2 n = 17 birds per mean 3 Body weight prior to slaughter following feed and water deprivation for 10h 4 Carcass weight after exanguination prior to evisceration with legs and neck left in the carcass. 5 Without giblets but with abdominal fat pad left in the carcass. 6 Without giblets after chilled in an ice-slush tank for 24 h 7 Plucked carcass weight / live BW after feed and water deprivation x 100. 8 Hot carcass weight / live BW after feed and water deprivation x 100. 9 Cold carcass weight / live BW after feed and water deprivation x 100. 1 Table 3. The effect of SM included at different levels in broiler diets on carcass cuts and abdominal fat yields as percentage of live weight 1, 2. Carcass Cut 0% SM 3% SM 6% SM 9% SM Neck 4.1 4.4 4.2 4.1 Feet 20.2b 22.4a 22.3a 22.6a Back 15.2 13.7 13.7 14.5 Wing 16.7 16.5 15.8 16.9 a 24.8 a 24.7 21.3b 22.5 22.3 22.4 24.2 Breast a 52.2 a 49.3 a 48.2 40.3b Abdominal fats 0.53 0.43 0.45 0.55 Thigh Drumstick ab 23.4 a-b Means in a given row bearing different superscripts differ significantly at P < 0.05. 1 Values given in this table correspond to least-squares means obtained from ANOVA and their pooled SEM. 2 n = 10 birds per mean 5 Shrimp Industry Organic Wastes 14 d - old broiler chicks 6 Literature Cited Association of Official Analytical Chemists. AOAC. 1990. Official Methods of Analysis. Williams, J. (ed). Arlington, VA. Cunha, F. S., C. B. V. Rabello, M. C. M. M. Ludke, W. M. Dutra, R. R. S. Loureiro, R. C. Lucas, L. Piaggio, and E. R. Prates. 2003a. Use of shrimp meal in the feeding of broiler chickens. IX World Conference on Animal Production. Porto Alegre, Brasil. Cunha, F. S., C. B. V. Rabello, M. C. M. M. Ludke, W. M. Dutra, V. R. B. A. Rocha, C. R. G. de Freitas, and F. B. Lima. 2003b. Effect of shrimp meal on carcass yield in broiler chickens. IX World Conference on Animal Production. Porto Alegre, Brasil. Damron, B.L., P.W. Waldrup, and R.H. Harms. 1964. Evaluation of shrimp meal in broiler diets. Poultry Science Mimeograph Series No. PY65-1. University of Florida, Gainesville, Fl. Ewing, R., 1963. Handbook of Poultry Nutrition. J.J. Little and Ives Co. South Pasadena, CA. Gernat, A.G. 2001. The effect of using different levels of shrimp meal in laying hen diets. Poultry Sci. 80: 633-636. Ilian, M.A., C.A. Bond, A.J. Salam, and S. Al-Hooti. 1985. Evaluation of shrimp by-catch meal as broiler feedstuff. Nutr. Rep. Int. 31: 487-492. Islam, M.A., M.D. Hossian, S. M. Baibul, and M.A.R. Howlider. 1994 Unconventional feed for broilers. Indian Vet. J. 74: 775-780. Meyers, S.P. and J.E. Rutledge, 1971. Shrimp meal – A new look at an old product. Feedstuffs 43 (49):31. National Research Council (NRC), 1994. Nutrient Requirements of Poultry. 9th rev. ed. National Academy Press, Washington, D.C. Rosenfeld, D.J., A.G. Gernat, J.D. Marcano, J.G. Murillo, G.H. Lopez, and J.A. Flores. 1997. The effect of using different levels of shrimp meal in broiler diets. Poultry Sci. 76: 581-587. SAS Institute, 1990. SAS® / STAT guide for personal computers. Version 6.12 edition. SAS Institute Inc. Cary, NC. Singletary, J. R., D.J. Bray, and H.J. Davis. 1935. Shrimp meal as a protein supplement for chickens. Page 31 in: Bulletin 262. Louisiana State University, Baton Rouge, LA. 7 Viability of poultry litter compost on growth of Brachiaria brizantha cv. Mulato and pollutant effects in the soil Emérita García Pizarro and Elide Valencia Department of Agronomy and Soils, University of Puerto Rico, Mayagüez Abstract Composted poultry litter (CPL) applied to field crops can be an important source of nutrients and organic matter to improve soil quality. However, little is known on the effects of CPL on tiller dynamics and forage yield of the tropical grass Brachiaria brizantha cv. mulatto. A study was conducted in the fall of 2003 and spring of 2004 to evaluate four CPL rates and their influence on number of tillers, herbage mass and crude protein (CP) concentration of cv. Mulato at three successive harvests at 30-d intervals. Treatments included 0 (Control; C), 16 (low; L), 31 (Medium, M), and 62 kg/ha of N (High; H) CPL rates. Grass seedlings (6-wk old) were established in pots (1-gl) filled with soil of the Consumo type (Fine, mixed, semi-active, isohyperthermic Typic Haplohumults). Composted poultry litter was broadcastapplied and incorporated into the first 2-cm of the soil in the pots. Plants were irrigated as needed. From first to third harvest, there was a minimal increase in tiller count (8.4 to 11) for the control. Corresponding increases observed for the L and M CPL rates were 14 to 28 and 21 to 28 tillers/plant. However, the magnitude of change in tiller counts at the H CPL rate was much greater (21, 23, and 44) at first, second and third harvest, respectively. There was also a linear effect (P<0.05) of CPL rates on herbage mass (g/plant on dry matter basis). For C, there were no changes in herbage mass from first to last harvest (mean of 16 g per plant). For the L and M rates of CPL minimal changes in herbage mass were noted from the first to third harvest. Herbage mass increases from 31 to 56, and 81 g/plant at first, second, and third harvest, respectively at the H CPL rate. There were differences in CP of cv. Mulato with increasing rates of CPL. Crude protein averaged 7.2, 6.6, 7.2, and 9.1% for the C, L, M, and H rates, respectively (a 2 percentage unit increase over C with H CPL). An important aspect of this study is that cv. Mulato can serve as a sink for this nutrient-rich compost and also provide an environmentally acceptable use of CPL. Resumen La composta de gallinaza puede aplicarse a suelos cultivados como un recurso importante de nutrimentos y material orgánico para promover la calidad del suelo. No obstante, no conocemos los efectos de la misma en la dinámica de brotes y rendimiento de forraje en la gramínea tropical Brachiaria brizantha cv. Mulato. Un estudio fue conducido en otoño de 2003 y primavera de 2004 para evaluar cuatro tratamientos de gallinaza y sus influencias en el número de brotes, masa de forraje y concentración de proteína cruda (PC) de cv. Mulato en tres cosechas en intervalos de 30 días. Los tratamientos abarcaron 0, (Control; C), 16 (Bajo: B), 31 (Mediano; M) y 62 kg/ ha de N (Alto; A) niveles de gallinaza aplicadas en base a nitrógeno. Las plantas (seis semanas de edad) fueron sembradas en tiestos (1-gl); utilizando para ello suelo de la serie Consumo (Fino, mixto, semiactivo, isohipertérmico Típico Haplohumults.). La gallinaza fue distribuida e incorporada en los dos primeros centímetros del suelo en cada tiesto. Las plantas fueron irrigadas según necesidades. De la primera cosecha a la tercera hubo un crecimiento mínimo en brotes (8.4 a 11 brotes) para el control. Incrementos observados para los tratamientos B y M fueron 14 a 28 y 21 a 28 brotes por planta, respectivamente. Sin embargo, la magnitud del cambio en número de brotes en el tratamiento A fue mucho mayor (21, 23 y 44) en la primera, segunda y tercera cosecha, respectivamente. Se verificó un efecto linear (P< 0.05) de nivel de gallinaza sobre la biomasa (g de materia seca/planta). Para C no hubo cambio de la biomasa de la primera a la última cosecha (promedio de 16g/planta). Cambios mínimos en biomasa fueron notados de la primera a la tercera cosecha para los tratamientos B y M. La masa de forraje aumentó de 31 a 56 y 81 g/planta en la primera, segunda y tercera cosecha, respectivamente en el tratamiento A. A medida que aumentaba el nivel de gallinaza, aumentaba el contenido de PC. La PC promedio fue 7.2, 6.6, 7.2 y 9.1% para C, B, M, y A, respectivamente. (Un aumento de 2 unidades de porcentaje con A sobre C). Un aspecto importante de este estudio es que el cv. Mulato puede servir para absorver los altos contenidos de nutrientes presentes en esta composta y constituir un uso de gallinaza ambientalmente benigno. 8 Introduction The local livestock industries are dependent on tropical pastures to meet their nutritional demand. Nitrogen is the most limiting nutrient for pasture production in Puerto Rico. Most of the soils used for pastures are mainly acidic (Oxisols and Ultisols). These soils have low organic matter content, and are prone to erosion. Grass production relies on inorganic fertilizers, thus increasing cost of production. Nitrate leaching and subsurface lateral flow toward streams and rivers is a major cause of contamination of groundwater and other water resources. Phosphorus is also a major concern (Havlin et al., 1990). According to Hornik, (1992), the quality of soil has traditionally been associated mainly with its productivity. This definition has now been expanded to include the capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health. An alternative for improving soil quality is the use of compost. Poultry litter (PL) is generated in large quantities on the island. The Department of Agriculture of Puerto Rico reports an average yearly population of 8.2 million chickens which yield approximately 71,500 metric tons of manure (Muñoz et al., 1990) which represent an alternative to use for organic matter maintenance of low fertility soils. According to Martinez and Guzman (1999), composting is a cost effective and environmentally sound alternative for PL recycling. On clay soils, good quality compost can improve soil structure, reduce surface crusting and compaction, promote drainage, and provide much needed nutrients. In sandy soils, compost increases water and nutrient retention, supplies nutrients, and increases microbial activity. In an evaluation of time and mode of application of chicken manure for plantain production, an adverse effect was observed during germination with the application of 7.26 kg manure per plant at planting (Muñoz and Martínez, 1991). In other studies PL was shown to promote faster turf establishment, improve turf density and color, increase root growth, and lower the requirements of inorganic fertilizer and irrigation (Landschoot, 1996). Composts can supply all or most of the turf’s nutrient requirement (i.e. N, P, S, K, Fe, Zn, Cu, and Mg). Studies with biosolids show that only about 10 percent of the N is available to plants during the first growing season. Certain types of compost have a high concentration of soluble salts, such as those made with spent animal manures. Those salts increase the electrical conductivity of the soil with compost additions, sometimes approaching limits considered detrimental to crop growth (Martínez and Guzmán, 1999; Landschoot, 1996). Another problem is its variable pH as very 9 high (>8.5) or very low (<5.5) values can be detrimental to turf. The extremes in pH affect the availability of nutrients for plant use. Also, compost made from biosolids was shown to have higher heavy metal concentrations than those made from other sources. Applications of biosolids have been shown to significantly increases levels of EDTA extractable metals (e.g., Cu, Zn, Cd, Cr, and Fe) (Martínez and Guzman, 1999). Information on the use of PL on pasture crops in Puerto Rico is limited. Studies are needed to assess the effects of varying levels of composted poultry litter (CPL) on the chemical and biological properties of soils and on grass growth. Objective The present research investigated CPL litter effects on tiller dynamics, biomass and CP percentage of Brachiaria brizantha cv. mulato harvested at 30-d intervals. Material and Methods This experiment was conducted at the University of Puerto Rico, Mayagüez Campus. Soil type was an Ultisol, Consumo clay, (Fine, mixed, semiactive, isohyperthermic Typic Haplohumults). At initiation of the experiment in 2003, field soil samples (taken at 0-30 cm depth) and CPL (produced at Vivero Finca in Bayamón) were analyzed for major and micro-nutrients (Tables 1 and 2). Treatments included 0 N (control; C), 16 (L), 31 (M), and 62 kg/ha of N (H). Grass seedlings of cv. Mulato (6-wk old) were transplanted in pots (1-gl size) and CPL broadcast applied and incorporated into the first 2-cm of the soil. Plants were maintained in an open green-house and irrigated as needed. Plants in each pot were harvested by clipping to a 15- cm height every 30-d. At harvesting, the number of tillers was counted and recorded. The fresh weight of the clipped plants (g/plant) was recorded and full samples were dried in an open-draft oven at 60° C for 48 hrs and dry matter percentage calculated. Dried samples were then ground in a Wiley mill to pass a 1-mm screen. Ground samples were analyzed for N following the procedures described by AOAC (1990) and CP calculated (N*6.25). Treatments (CPL levels) were arranged in a randomized complete block design and replicated five times. Data were analyzed using the GLM procedure of SAS (1990). Because of changes over time, data were sorted and analyzed by harvest date. Treatment comparisons were made using single degree of freedom contrasts for linear, quadratic and cubic effects of CPL rates. 10 Results and Discussion Table 1. Composition of soil analyzed at two depths (Fine, mixed, semiactive, isohyperthermic Typic Haplohumults) and of composted poultry litter (CPL). Organic Matter* Sample K* Mg* Ca* N* P** CEC*** pH Soil 0-4” depth 2.1 3.1 21.1 49.6 .2 3 21.4 5.5 4-6” depth 2.6 6.7 25.2 57.7 .2 21 22.2 6.3 9.9 65.1 14.8 20.1 2 238 46.3 9.1 Poultry Litter * Values are in percent ** P values are in ppm *** Values are in meq/100g Table 2. Micro-nutrients and sulfur composition of soil at two depths and of composted poultry litter (CPL). Soil Metal (ppm) 0-4”† Sulfur Zinc Manganese Iron Copper Boron 139 2.4 55 31 3.9 0.3 CPL 4-6”† 322 5.4 84 39 4.5 0.8 964 58.9 126 60 4.9 3.8 † Soil depth There were significant (P<0.05) effects of PL rate, harvest date and PL rates by harvest date interaction on tiller dynamics of cv. Mulato. In the data analyzed by harvest date, there was a linear response (P<0.05) to increasing rates of CPL. From the first harvest to the third, there 11 was minimal increase in number of tillers (8.4 to 11) in the control treatment without CPL. Similar increases were observed for the L and M rates. Major changes, however, were noted for the H rate (21, 23, and 44 tillers per plant) at first, second and third harvest, respectively (Figure 1). Figure 1. Number of tillers per plant for four CPL treatments at 30 (A), 60 (B) and 90-d (C) harvests. Treatments High Medium Low Control 0 20 40 60 80 100 Yield gram/plot A Figure. 2. B C Dry matter yield (g/plot) for four CPL treatments at 30 (A), 60 (B) and 90-d (C) harvest.. 12 There was also a linear effect of CPL rates on dry matter (DM) yield (g/plant). For the control, there were no changes in DM yield from first to last harvest (average of 16 g per plant). For the L and M rates of CPL minimal changes in dry weight of plants were observed from the first to third harvest. However, at the H rate of CPL, there were major changes in dry matter yield. Yields per plant of 31, 56, 81 g at first, second, and third harvest, respectively were recorded (Figure 2). The increase in DM at third harvest is highly correlated to number of tillers (44 tillers/plant). There were differences in CP concentration of cv. Mulato with increasing application of CPL. Crude protein averaged 7.2, 6.6, 7.2, and 9.1% for the C, L, M, and H rates, respectively. Thus there was nearly a 2 percentage units increase in CP with the H rate of CPL over C. Conclusions Our results show positive linear responses for both number of tiller and DM yield of cv. Mulato to the high rate of CPL (62 kg/ha N). The increased DM yield due to the H CPL rate compared to that of the control at the third harvest may indicate mineralization of N and more N available for plant use. This gives CPL the quality of a slow release fertilizer. The two percentage units increase observed in CP with addition of the H rate of CPL indicates that CPL could serve to increase the nutritive value of cv. Mulato. Soil analysis is needed to determine the corresponding changes in soil pH, and P and other mineral accumulations in the soil. Because of the slow release of N from CPL, there would be less leachate of N in the system. An important aspect of this study is that cv. Mulato or other tropical grasses can serve as a sink for this nutrient-rich compost and also provide an environmentally acceptable and hopefully use of poultry litter compost. 13 Brachiaria brizantha cv. Mulato Mulato grass seedling (6 -wks old). Brachiaria brizantha first day of experiment Brachiaria brizantha on the 30th day. Plant appearance after each treatments, Control, Medium, Low and High rates 14 Literature Cited AOAC. 1990. Official Methods of Analysis. 15th Ed. Association of Official Analytical Chemist. Arlington, VA. Havlin JL, D.E. kissel DE, and L.D Maddux. 1990. Crop rotation and tillage effects on soil organic carbon and nitrogen. Soil Sci. Soc.Am. J. 54: 448-452. Hornik SB (1992) Factor affecting the nutritional quality of crops. Am. J. Altern. Agric 7:63-68 Landschoot, P. 1996. Using compost to improve turf performance. Pennsylvania State University. Technical Bulletin. College of Agricultural Sciences Cooperative Extension Services. Martinez, G. and J.L. Guzman. 1999. Chemical and physical properties of two tropical soils treated with sewage sludge compost. J. Agric. Univ. PR. 83:103-121. Muñoz, M. A., and G. Martinez, 1991. Chicken, manure: An organic fertilizer for plantains ( Musa accuminata x M. balbisiana AAB). Proc. Caribbean Food Crops Society 27:225-233, Roseau, Dominica. Muñoz, M., O. Colberg and J.A. Dumas. 1990. Chicken Manure as an Organic Fertilizer.J. Agric. Univ. P.R. 74: 139-145. SAS Institute. 1990. SAS/STAT® User’s Guide (Release 8.1). SAS Inst. Inc., Cary, N.C. 1686 pp. 15 Fermentation characteristics and aerobic stability of orange pulp silage treated with urea Jonael Bosques Méndez, Abner A. Rodríguez and Danilo Cianzio Department of Animal Industry, University of Puerto Rico, Mayagüez Campus Abstract The objective of this study was to determine the fermentation characteristics of orange pulp (OP) treated with urea. The aerobic stability of fresh and fermented OP was also evaluated. The four treatments tested were OP without urea and with 1, 3, and 5% urea (w/w). Mixtures were fermented (N=3) in micro-silos for 30 and 60 d. Samples from each treatment were collected at 0, 30 and 60 d to determine pH, chemical composition and fermentation products. Results showed that it is possible to ferment OP for 30 or 60 d without affecting the original chemical composition of the fresh residue. After 30 and 60 d of ensiling, acetic acid content was similar (P<.05) for all treatments, but adding urea increased (P<.05) lactic acid content as compared to OP fermented alone. For aerobic stability determination, samples of fresh and fermented OP were exposed to air during 0, 1, 3, and 6 (fermented) or 0, 1, 3, 6, and 9 d (fresh). Samples from each treatment and corresponding day of exposure were analyzed to determine pH and yeast and mold (YM) populations. Temperature was monitored daily and OP recovery percentage calculated after each exposure time. Deterioration of fresh OP increased directly with days of aerobic exposure. During the whole exposure period pH was lower, but rise in temperature faster (P<.05) in control OP that in OP treated with urea. The YM population was higher (P<.05) after 1 and 3 d of aerobic exposure in control than in urea-treated fermented OP, but was similar after 6 d. Recovery of OP was similar for all treatments. In conclusion, 30 d is sufficient to ferment OP. Fresh OP is more unstable to aerobic conditions than the fermented waste. The use of urea improved the quality of the silage and progressively slowed the aerobic deterioration of fermented OP as level of urea increased. Resumen El objetivo de este experimento fue determinar las características fermentativas de pulpa de naranjas (PN) tratada con urea. Se evaluó también la estabilidad aeróbica del residuo fresco y fermentado. Se probaron 4 tratamientos; PN sin urea o con urea al 1, 3 y 5% (p/p). Las mezclas se fermentaron en microsilos durante 30 y 60 d. Muestras de cada tratamiento después de 0, 30 y 60 d fueron analizadas para determinar pH, composición química y productos de fermentación. Los resultados demostraron que es posible fermentar PN durante 30 ó 60 d sin afectar la composición química original del residuo fresco. El contenido de ácido acético fue similar (P<.05) entre tratamientos y períodos de fermentación. El contenido de ácido láctico fue mayor (P<.05) en ensilajes con urea que en PN fermentada sola. Para determinar la estabilidad aeróbica, se expuso al aire muestras de PN fresca y fermentada durante 0, 1, 3, y 6 d (fermentada) y 0, 1, 3, 6, y 9 d (fresca). Se determinó pH y población de hongos y levaduras (HL) después de cada período de exposición aeróbica. La temperatura se registró diariamente y la recuperación de PN fue calculada después de 1, 3, y 6 ó 9 d. La PN fresca se deterioró progresivamente al transcurrir el período de exposición al aire. A través del período de exposición aeróbica, el pH fue menor (P<.05) en PN control que PN ensilada con urea. Después de 1 y 3 d de exposición al aire la temperatura y la población de HL fue mayor (P<.05) en PN control que en los tratamientos conteniendo urea, pero fue similar después de 6 d. El porcentaje de recuperación de PN fue similar entre tratamientos. En resumen, 30 d es suficiente para fermentar PN. La PN fermentada es más estable a condiciones aeróbicas que el residuo fresco. El uso de urea mejoró la calidad del ensilaje. El deterioro aeróbico de PN fermentada fue más lento según aumentó el contenido de urea. 16 Introduction Orange pulp (OP) is an organic waste resulting from the operation of a juice processing plant. In Puerto Rico, this by-product has been partially used in direct feeding to dairy cows, or otherwise disposed of in landfills, a practice that represents increased operational costs for the industry and a source of environmental pollution for the island. The orange juice plant “Productores de Citrícos de la Montaña”, located in the center of the island, produces in a normal day of operation 25m3 of wet citrus pulp. Therefore, alternatives for the disposal of this by-product need to be evaluated. Silage production has been identified as one such possible alternative. However, the combined effect of high water soluble carbohydrates content of the citrus pulp and the high temperatures of the local tropical environment could lead to rapid deterioration of the fresh material, an undesirable type of fermentation (alcoholic), and poor aerobic stability of the fermented waste. The practice of adding a non-protein nitrogen source has been reported to improve the fermentation characteristics and aerobic stability of grass silage (Woolford, 1990), but there is limited information regarding the use of urea as an additive on the ensiling characteristics of OP. The objective of this study was to determine the fermentation characteristics of OP silage treated with 3 levels of urea. The aerobic stability of fresh and fermented OP was also determined. Materials and Methods The study was conducted in the Animal Nutrition Laboratory, University of Puerto Rico, Mayagüez Campus. The organic waste was obtained from the “Productores de Cítricos de la Montaña” processing plant. For the fermentation studies, OP was fermented alone or mixed with urea (non-protein nitrogen source) at three different levels; 1, 3, and 5 % (w/w). Mixtures were allowed to ferment in PVC lab micro-silo (1.2 kg capacity) for 30 and 60 days (Fig. 1). Triplicate samples from each treatment and length of fermentation were analyzed to determine pH, chemical composition (AOAC, 1991), and fermentation end-products. Data were analyzed as a completely random design with a 4 (levels of urea, 0, 1, 3, and 5 %) by 3 (length of fermentation, 0, 30, and 60 d) factorial arrangement of treatments (Steel and Torrie, 1980) using the General Lineal Model subroutine of SAS (1990). The Bonferroni t-test was used for separation of means. To determine the aerobic stability of the fresh residue and fermented product treated with or without urea, triplicate samples (2 kg) of fresh or fermented OP were place into styrofoam containers lined with plastic and exposed to air for 6 days (Fig. 2). Samples were collected at 0, 1, 3, 6 (fermented) and 9 (fresh material only) d to determine pH, 17 and yeast and mold (YM) populations. Temperature was monitored daily. Fresh and fermented material recovery percentage was calculated form each time of exposure. Statistical analysis of the pH and YM populations data was performed as a completely randomized design with a 4 (levels of urea) by 4 or 5 (periods of aerobic exposure) factorial arrangement of treatments (Steel and Torrie, 1980) using the General Lineal Model subroutine of SAS (1990). The models for temperature and OP recovery percentage were similar except that 7 (temperature) and 3 ( fermented) or 4 (fresh) periods of aerobic exposure were utilized, respectively. For all models, mean separation was performed by Bonferroni t-test. Fermentation Characteristics Results and Discussion For both lengths of fermentation pH was lower (P<.05) in control silage than in OP ensiled with urea. In OP treated with the non-protein nitrogen source, final pH was higher (P<.05) as level of urea increased in the mixture, however, acidity of all the urea treated silages complies with the criteria to be considered as good quality silage. As expected, for both lengths of fermentation contents of organic and inorganic matter and cell wall fractions were not affected by the addition of urea during the OP ensiling process. The total equivalent crude protein content (%N * 6.25) increased as level of urea was increased in the mixture. Lactic acid content was higher (P<.05) in OP ensiled with urea than in the control, but acetic acid content was similar (P<.05). None of the urea containing silages reached a lactic acid content greater than 1.5% dry matter basis (DMB), which is the concentration of lactate required in the ensiling of forages to be considered as good quality silage. The pH value of OP is typically 3.0 – 4.0 and the buffering capacity 224-228 milliequivalents/kg DM (Crawshaw, 2001), these being factors that might affect the microflora associated with lactic acid production. However, the predominant organic acids in OP, citric and malic (Ting and Attaway, 1971), kept the pH lower than 4.2, which is the acidity desirable to avoid proliferation of undesirable microorganisms. Aerobic Stability Air deterioration of fresh OP increased directly with length of aerobic exposure as evidenced by changes in pH, temperature, YM populations, and OP recovery (Table 2). The decreases from 0 to 1 d of aerobic exposure in acidity, heat production and proliferation of YM plus an appreciable loss of recoverable OP detected after 1 d might indicate that a large part of the deterioration of OP occurs within the initial 24 hours. 18 During the whole aerobic exposure period pH was lower (P<.05) in control silage than in that treated with urea. Rise of temperature was faster in control and OP silage treated with 1% urea than in those of 3 and 5 %. The YM population was also higher (P<.05) at 1 and 3 d of exposure in control OP than in urea containing silages. However, recovery of OP (%) was similar for all treatments throughout the exposure period. These results suggest that addition of 3 or 5% urea might reduce the deterioration of OP silage during the first 24- 36 h after exposure to air. Table 1. Fermentation characteristics of orange pulp treated with urea and ensiled for 30 or 60 days Component Length of fermentation (d) pH Control 1 Urea (%) 3 5 0 30 60 4.76 3.78c 3.74c 3.36 4.02b 4.06b 3.60 4.05b 4.15b 4.60 4.85a 4.65a Organic Matter 0 30 60 94.20 94.20 92.12 96.01 93.34 93.93 92.12 94.69 94.70 94.89 96.01 95.36 Inorganic Matter 0 30 60 5.31 5.79 7.88 3.98 6.65 6.06 7.88 5.31 5.29 5.10 3.98 4.64 Crude Protein2 0 30 60 4.46 6.22d 7.07d 6.28 19.04c 11.55c 4.52 44.81b 38.83b 5.56 56.10a 51.81a Cell wall 0 30 60 22.12 29.31 25.14 23.05 32.61 25.37 16.56 27.56 28.10 24.32 24.30 24.87 Lactic acid 0 30 60 0.04 0.23c 0.48c 0.01 0.63a 0.76b 0.01 0.42b 0.92a 0.03 0.40b 1.01a Acetic acid 0 30 60 0.24 0.05 0.13 0.37 0.18 0.25 0.18 0.11 0.25 0.09 0.07 0.25 Chemical Composition1 (%) Fermentation Products1 (%) a,b 1 2 Means in the same row differ (P<.05) DMB % N * 6.25 19 Fresh Orange Pulp Anaerobic Fermentation (30 and 60 days) Orange Pulp Silage Figure 1. Orange pulp ensiling process 20 Table 2. Stability of fresh and fermented orange pulp treated with urea exposed to aerobic conditions during 6 days. Component Aerobic exposure (d) pH Fresh Orange Pulp 0 1 3 6 9 3.76 3.74 3.71 3.38 3.23 Temperature, °C 0 1 3 6 9 25.53d 38.88a 37.40b 30.37c 32.59c Yeast and Molds (ufc/g) 0 1 3 6 9 4.39c 6.15b 7.71a 6.52b 7.68a Organic Pulp Recovery (%) 1 3 6 9 95.83a 87.30b 82.00bc 77.93c Control 1 Urea (%) 3 5 0 1 3 6 3.36c 3.33c 4.00b 3.44c 3.78b 3.75c 4.34a 4.63b 4.05ab 4.00c 4.30a 4.67b 4.15a 3.92c 4.38a 5.28a Temperature, °C 0 1 3 6 22.00 27.04 32.22a 29.66a 22.16 27.22 32.38a 31.67a,b 22.01 26.50 30.42b 30.19a 22.37 26.50 27.43b 28.75b,c Yeast and Molds (ufc/g) 0 1 3 6 3.05a 5.67a 8.25a 7.16c 3.83a 3.99b 5.53c 8.83b 2.57b 2.17c 6.63b 9.58a 1.45c 1.82d 5.78c 9.16a Organic Pulp Recovery (%) 1 3 6 88.56 87.76 85.21 90.00 88.09 84.44 86.43 88.42 87.04 89.86 89.42 86.25 pH a,b,c, Means in the same row differ (P<.05) 21 Day 1 Day 0 Day 6 Day 3 Day 9 Figure 2. Deterioration of fresh orange pulp exposed to air during 9 days 22 Conclusions It is possible to ferment OP during 30 or 60 d without greatly affecting the nutritive profile of the fresh product. Deterioration of fresh OP increased directly with length of aerobic exposure. Addition of urea improved the quality of the silage and its aerobic. Literature Cited AOAC. 1991. Official Methods of Analysis. Association of Official Analytical Chemist, Washington, D.C. Crawshaw, R. 2001. Co-product Feeds. Animal feeds from the food and drinks industries. Nottingham University Press. Nottingham, NG11 OAX, UK. SAS (1990). SAS User’s Guide: Statistics. SAS Inst., Cary, N.C. Ting, S.V. and J.A. Attaway. 1971. Citurs fruits. In: The biochemistry of Fruits and their Products. Vol-2, ED. A.C. Hulme, Academic Press. Woolford, M.K. 1990. The detrimental effect of air on silage. J. Appl. Bact. 68:101. 23 Fermentation and aerobic stability of silages made of rice hulls hydrated with milk Maritere Crespo, Angel A. Custodio and Abner A. Rodríguez Department of Animal Industry, University of Puerto Rico, Mayagüez Abstract In Puerto Rico, milk (M) that does not meet minimum standards for human consumption is rejected and dumped in the waste lagoons of dairy farms, which contributes to pollution and constitutes a loss of unutilized nutrients. Rice hulls (RH), although of low nutritional value, are in abundant supply and accessible especially in the most intensive dairy farming zone of the island and may be used to recycle the milk as silage. The purpose of the present study was to evaluate the quality and aerobic stability of silages made from rice hulls hydrated with different levels of milk. The experiment was performed with seven treatments: 1) Control (39%water 61% rice hulls w/w), 2) 35M:65RH, 3) 42M:58RH, 4) 45M:55RH, 5) 50M:50RH 6) 60M:40RH and 7) 70M:30RH w/w, ensiled in micro-silos of PVC pipes in triplicate. Silos were opened after 14 and 28 days. To evaluate quality, pH and fermentation products were measured in three samples from each treatment, at 0, 14 and 28d. For the aerobic stability determination, pH and temperature were measured the day the silo was opened and for the next three days. An analysis of variance was performed with treatment and days of fermentation as independent variables. Results showed a pH level of about 3.8 at 14d and 3.9 at 28d for all treatments with 50%M or more. Major fermentation product was lactic acid in all treatments except the control, in which butyric acid was more abundant. Lactic acid concentration was highest (P<0.05) for 50 and 60%M treatments reaching a level of about 2% by 14d and remaining at that level until 28d. For the 70M treatment it reached a peak of 1.76% at 14d. Butyric, acetic, propionic and isobutyric acids concentrations remained below 0.5% in all treatments. These results indicate that proportions of 50 and 60%M ensiled best. The aerobic stability determination showed that the control did not ferment well nor did it deteriorate much after opening the silo. At 24 hour of aerobic exposure temperature increases (P<.01) of the other six silages ranged from 6°C to 17°C, with the highest increase being observed with 70%M. Similarly, silage pH tended to increase (P<.01) with time more markedly as level of milk increased. After three days of aerobic exposure all silages were badly damaged. The mixture of milk to rice hulls in nearly equal proportions generates a good fermentation, but the resulting silage deteriorates fast upon aerobic exposure. Ensiling milk with other more nutritive materials, such as straw or hay, should be even more successful as a method of preserving the nutrients of discarded milk for animal feeding and thus contributing to reducing soil and water contamination. Resumen En Puerto Rico, la leche (M) cruda que no cumple con los requisitos mínimos para el consumo humano es descargada en las lagunas de desecho o “charcas de oxidación” de las vaquerías. Esta manera de descartar la leche contribuye a la contaminación y no permite la utilización de sus nutrientes. La cascarilla de arroz (RH), a pesar de su bajo valor nutritivo, es abundante en la zona ganadera más intensa de la isla, y por lo tanto, puede ser utilizado para reciclar la leche como ensilaje. El propósito de este estudio es evaluar la calidad y la estabilidad aeróbica de ensilajes hechos de RH hidratada con diferentes niveles de M. El experimento se realizó con siete tratamientos en triplicado: 1) Control (39% agua 61%RH ), 2) 35M:65RH, 3) 42M:58RH, 4) 45M:55RH, 5) 50M:50RH 6) 60M:40RH y 7) 70M:30RH peso/peso, ensilados en micro-silos hechos de tubos de PVC. Los silos se abrieron a los 14 y 28 días. Su calidad se evaluó midiendo el pH y los productos de fermentación de tres muestras de cada tratamiento a 0, 14 y 28 días de fermentación. La estabilidad de los ensilajes expuestos al aire se determinó midiendo su pH y temperatura el día que se abrieron los silos y por los próximos tres días. Se realizó un análisis de varianza con tratamiento y días de fermentación como las variables independientes. Los resultados muestran que el nivel del pH a los 14 y 28 días fue de 3.8 y 3.9, respectivamente, para los tratamientos con 50%M o más. El producto de fermentación más abundante en todos los tratamientos con M lo fue el ácido láctico. En el control, que no tenía M, el ácido butírico fue el más abundante. La concentración de ácido láctico más alta (P<0.05) fue para los tratamientos con 50 y 60%M con un nivel cerca de 2% a los 14 y 28 días. El tratamiento con 70%M alcanzó un pico de 1.76% de ácido láctico a 24 los 14 días. Las concentraciones de los ácidos butírico, propiónico, acético e isobutírico permanecieron por debajo de 0.5% en todos los tratamientos. A las 24 horas de exposición al aire la temperatura aumentó de 6 a 17°C (P <0.01) en los seis tratamientos con M, siendo el aumento más alto para el ensilaje con 70%M. El pH presentó una tendencia similar, aumentando más (P<0.01) con el paso del tiempo a medida que aumentó el nivel de M en el ensilaje. A los tres días de exposición aeróbica todos los ensilajes estaban degradados. Los resultados indican que las mezclas con proporciones casi iguales de M y RH ensilan bien, pero entre más leche contiene el ensilaje más rápidamente se degrada cuando se expone al aire. El ensilar leche con otras materias más nutritivas, como heno o paja, debiera ser mejor alternativa para preservar los nutrientes de la leche y utilizarlos para la alimentación animal, contribuyendo así a reducir la contaminación ambiental. Introduction In Puerto Rico thousands of quarts of milk that do not meet the minimum standards set for human consumption are rejected annually on dairy farms. In 2002-2003 the total was 1,208,680 quarts of raw milk, of which 511,920 quarts were rejected because of antibiotic content (Annual Report of Dairy Industry of Puerto Rico, 2002-2003). This milk is discarded in waste lagoons where its nutrient content is wasted and the effluent from its decomposition might leak and pollute underground water (Weinberg et al., 2003). Milk has high nutritional value due to its protein, fat, sugar and mineral content. Weinberg et al. (2003), in Israel, successfully ensiled straw by addition of milk for use as an animal feed. The objective of this study is to evaluate the quality and aerobic stability of silages made of rice hulls hydrated with milk. If we can obtain good and stable silage by this procedure, the Office for the Regulation of the Dairy Industry of Puerto Rico would have the option of allowing the rejected milk to be ensiled rather than dumped in waste lagoons. Putting a sufficient amount of vegetable dye in the condemned milk would be a way to ensure that this milk is not used for human consumption. Materials and Methods The study was conducted in the Animal Nutrition Laboratory, University of Puerto Rico, Mayagüez Campus. It included seven treatments to test different ratios of raw milk (M) and rice hulls (RH). The rice hulls (Figure 1) were donated by Trofima Corporation of Arecibo and the raw milk was obtained from the dairy herd of the Agricultural Experimental Station of the University of Puerto Rico, Lajas. Treatments were: 1) Control (39%water 61% rice hulls w/w), 2) 35M:65RH, 3) 42M:58RH, 4) 45M:55RH, 5) 50M:50RH 6) 60M:40RH and 7) 70M:30RH w/w. The treatments were ensiled in sealed micro silos (1.2 kg capacity) made of PVC pipes (Figure 2), which were equipped with valves to permit the liberation of gases, and were maintained at 25 ambient temperature that ranged from 27 to 30 °C. Triplicates were prepared for each treatment and sampled at 0, 14 and 28 days of fermentation. Samples were analyzed for pH immediately after opening each silo (Figure 3) and frozen to be sent later to Dairy One Forage Lab in Ithaca, New York, for determination of fermentation end-products. To determine the stability of fermented rice hulls to aerobic exposure, 500g samples of silage were placed in styrofoam containers lined with plastic bags (Figure 4) and exposed to air for 3 days. Temperature of the silage was measured at days 0, 1, 2, and 3 while pH was measured at days 0, 1, and 3 of aerobic exposure. Dry matter recovery at days 1 and 3 of aerobic exposition was calculated as the difference in total dry matter relative to the initial quantity. Analyses of variance with treatment and days of fermentation as independent variables were performed using SAS GLM procedure (SAS, 1990). Differences among means were evaluated using Bonferroni comparisons. Results and Discussion Fermentation Characteristics The high pH and very low acetic acid content (Table 1) of the control silage demonstrate that it did not ferment well. Relatively high butyric acid of this silage is indicative of protein degradation due to lack of available carbohydrates in rice hulls. For all treatments with 50% of milk or more, average pH level was about 3.8 at 14d and 3.9 at 28d. Major fermentation product was lactic acid in all silages except the control, in which butyric acid although in low concentration, was the most abundant. Lactic acid concentration was highest (P<0.05) for 50 and 60% milk treatments reaching a level of about 2% by 14d and remaining at that level until 28d. For the 70M treatment it reached a peak of 1.76% at 14d and then declined slightly. Butyric, acetic, propionic and isobutyric acids concentration remained below 0.5% in all treatments. Results indicate that silages with 50 and 60% of milk fermented best. Aerobic Stability At 24 hour of aerobic exposure pH remained relatively stable for treatments with about 50% milk or less, but increased considerably for treatments with higher proportions of milk (Table 2). At three days of aerobic exposure pH increased (P<.01) considerably in all silages. Silage temperature changed faster than pH after aerobic exposure. At 24 hour of exposure temperature had increased considerably in all treatments, except in the control (Table 3), and 26 remained high at days two and three. The increment of temperature upon aerobic exposure was directly related to the level of milk added, with the highest increase observed in silage with 70%M. After three days of aerobic exposure silages that contained milk were badly damaged. Thus, mixtures of rice hulls and milk in proportions ranging from 65:35 to 40:60 showed a good fermentation, but the resulting silages deteriorated in less than 3 days upon aerobic exposure. Table 1. Treatments Chemical analysis at 14 and 28 days of fermentation of silages from rice hulls hydrated with varying proportions of milk 1 DM (%) pH Control 2 3 4 5 6 7 56.64 59.49 59.55 56.07 54.91 48.67 34.91 5.17 3.84 4.02 3.97 3.80 3.78 3.68 Control 2 3 4 5 6 7 51.13 61.89 59.57 56.62 56.85 51.03 46.23 4.97 4.06 4.04 4.02 3.75 3.93 3.74 Organic2 matter Inorganic2 matter Lactic2 acid Fermentation Length (14 d) 84.30 85.05 85.56 85.16 85.90 84.91 85.94 15.64 14.94 14.43 14.83 14.10 15.08 14.06 Fermentation Length (28 d) 83.66 84.81 85.97 85.09 85.27 84.14 84.71 16.33 15.19 14.69 14.91 14.72 15.85 15.28 Acetic2 acid Butyric2 acid 0.02 1.26 1.32 1.38 2.16 1.91 1.76 0.00 0.14 0.14 0.14 0.15 0.10 0.09 0.20 0.00 0.02 0.02 0.02 0.02 0.01 0.00 1.34 1.47 1.47 2.11 1.99 1.56 0.16 0.09 0.13 0.15 0.18 0.10 0.09 0.32 0.02 0.08 0.02 0.04 0.03 0.01 1 Control had 39% water and 61% rice hulls, treatments 2,3,4,5,6, and 7 had 35,42,45,50,60, and 70% milk (w/w), respectively. Dry matter basis 2 Table 2. Days of air exposure Change in pH over three days of aerobic exposure of silages made of rice hulls hydrated with varying proportions of milk Control 2 0 1 3 5.17 5.19 6.69 3.84 4.77 6.34 0 1 3 4.97 4.78 6.76 4.06 4.12 6.21 3 Treatments 4 Fermentation Length (14 d) 4.02 4.10 6.52 3.97 4.05 6.61 Fermentation Length (28 d) 4.04 4.08 5.48 4.02 3.97 6.42 1 5 6 7 3.80 3.92 6.26 3.78 5.75 8.05 3.68 5.95 7.69 3.75 3.83 4.66 3.93 3.81 6.68 3.74 5.53 7.84 Control had 39% water and 61% rice hulls, treatments 2,3,4,5,6, and 7 had 35,42,45,50,60, and 70% milk (w/w), respectively 27 Table 3 Days of air exposure Temperature (°C) change from day 0 to day 3 of aerobic exposure silages made of rice hulls hydrated with varying proportions of milk Treatments Control 2 3 4 5 6 7 0 1 2 3 25.40 26.66 30.00 30.36 25.76 37.40 28.51 29.25 0 1 2 3 24.03 26.50 33.30 29.43 25.40 32.20 34.23 31.10 Fermentation Length (14 d) 25.93 32.23 34.06 30.76 25.26 30.76 34.03 33.13 Fermentation Length (28 d) 25.60 32.23 33.53 35.16 25.36 26.33 33.86 32.20 25.55 37.40 28.51 29.25 25.92 41.10 38.88 37.58 25.55 39.99 44.07 36.66 24.74 28.15 28.88 37.03 24.25 32.40 32.40 43.51 24.81 45.18 44.62 42.03 1 Control had 39% water and 61% rice hulls, treatments 2,3,4,5,6, and 7 had 35,42,45,50,60, and 70% milk (w/w), respectively Fig. 1. Rice Hulls Fig. 2. Micro silos made of PVC pipes Fig. 3. Opening silos after 14 and 28 days of Fermentation Fig. 4. Sample of silage (500 g) placed in Styrofoam containers lined with plastic bags for the aerobic exposure period 28 Conclusions The mixture of milk to rice hulls in nearly equal proportions is conducive to a good fermentation, but the resulting silage deteriorates rapidly upon aerobic exposure. Ensiling milk with other more nutritive materials, such as straw or hay, should be even more successful as a method of preserving the nutrients of discarded milk for animal feeding and thus contributing to reducing soil and water contamination Literature Cited Wienberg Z.G., G. Ashbell, and Y. Chen. 2003. Stabilization or returned dairy products by ensiling with straw and molasses for animal feeding. J. Dairy Sci. 86:1325-1329. González G. and A. A. Rodríguez. 2003. Effect of storage method on fermentation characteristic, aerobic stability, and forage intake of tropical grasses ensiled in round bales. J. Dairy Sci. 86: 926-933. Rodríguez A. A., J. A. Acevedo, and E. O. Riquelme. 1997. Aerobic Stability of Native Tropical Grass Silage. Effect of propionic acid and length of aerobic exposure. Arch. Latinoam. Prod. Anim. 5(Supl. 1): 83-85. SAS Institute. 1990. SAS User’s Guide: Statistics. SAS, Inst., Cary, N.C. Oficina de la Reglamentación de la Industria Lechera. 2002. Informe Anual Año Fiscal 20012002. ORIL, Hato Rey, P.R. 29 Development of Fermented Liquid Diet Using Organic Wastes For Early Weaned Pigs Dianne Hernández, Paul F. Randel, and Abner A. Rodríguez-Carías Department of Animal Industry, University of Puerto Rico, Mayagüez Campus Abstract An experiment was conducted to determine the fermentation characteristics of a commercial weaning pig concentrate (CPC) mixed with liquid organic wastes from the pharmaceutical (SynerMax, SM), beverages (wastewater from a caramel processing plant; WWCP) and food industries (milk whey, MW and discarded milk, DM). The CPC physical form (pelleted, CPCP or grounded, CPCG) and the addition of a lactic acidproducing bacterial inoculant (LAPBI) were also evaluated. The experiment consisted of mixing the CPC (P or G) with the liquid wastes in a 2:1 (w/w) proportion and with (LAPBI) or without the bacterial inoculum (NLAPBI). Deionized water (DW) was used as control. Mixtures evaluated were SM-CPCPNLAPBI, WWCP-CPCP-NLAPBI, MW-CPCP-NLABPI, DW-CPCP-NLAPBI, DW-CPCG-NLAPBI, DW-CPCGLABPI, DM-CPCG-NLAPBI, and DM-CPCG-LABPI. To determine the fermentation characteristics triplicate samples from each mixture were placed in hermetic anaerobic digestors (1000 mL capacity) during 96 hours. Samples (50 g) from each mixture were taken at 0, 12, 24, 48, 72, and 96 h to determine pH and fermentation products (organic acids). During the entire fermentation period and for all mixtures, production of propionic, and butyric acid was minimal, reaching concentrations lower than 0.02%. After 96 h, mixtures containing SM, WWCP, and MW did not ferment satisfactorily. Fermenting DW with CPCG resulted in lower (P<.05) pH and higher (P<.05) lactic acid concentration than DW mixed with CPCP. Addition of LAPBI improved the fermentation characteristics of DW-CPCG as evidenced by higher lactic acid content. Mixtures containing DM and CPCG reached the optimum characteristics of typical fermented liquid diets (pH lower than 4.5 and lactic acid content greater than 1.5%). Addition of the microbial culture improved the fermentation characteristics of CPCG with DM. In summary, the mixture containing grounded commercial weaning pig concentrate and DM seems to be the better alternative to develop a liquid diet for early weaning pigs. Ground diets and the use of microbial cultures improved the fermentation process. Resumen Se realizó un experimento con el objetivo de determinar las características fermentativas de mezclas de un concentrado comercial para cerdos destetados de forma precoz (CCC) con residuos orgánicos líquidos de la industria farmaceutica (SynerMax, SM), de bebidas (aguas residuales de la industria de carmelo, ARIC) y de alimentos (suero de leche, SL y leche decomisada, LD). Se evaluó también la forma física del CCC, aperdigonado (CCCA) o molido (CCCM) y la adición de un inóculo conteniendo bacterias productoras de ácido láctico (BPAL). El estudio consistió en mezclar el CCC (A o M) con los residuos líquidos en proporción 2:1 (p/p), con (BPAL) o sin (NBPAL) la adición del inóculo microbiano. Se utilizó agua desionizada (AD) como tratamiento control. Las mezclas evaluadas fueron; SM-CCCA-NBPAL, ARIC-CCCANBPALI, SL-CCCA-NBPAL, AD-CCCA-NBPAL, AD-CCCM-NBPAL, AD-CCCM-BPAL, LD-CCCM-NBPAL y LDCCCM-BPAL. Para determinar las características fermentativas, muestras en triplicado de cada mezcla se colocaron con digestores anaeróbicos (capacidad de 1000 ml) durante 96 horas. Muestras (50 g) de cada mezcla se colectaron después de 0, 12, 24, 48 y 96 h para determinar pH y productos de fermentación (ácidos orgánicos). A través del periodo de fermentación en todos las mezclas evaluadas la producción de ácido propiónico y butírico fue mínima, obteniéndose concentraciones menores de 0.02%. Después de 96 h, las mezclas conteniendo SM, ARIC y SL no fermentaron satisfactoriamente. Al fermentar CCCM con AD se obtuvo un pH menor (P<.05) y una mayor (P <.05) contenido de ácido láctico que mezclas conteniendo AD con CCCA. La adición del inóculo de BPAL mejoró las características fermentativas de AD-CCCM, evidenciado por un mayor contenido ácido láctico. En mezclas conteniendo LD y CCCM se obtuvo características óptimas de fermentación para dietas líquidas (pH < 4.5 , concentración de ácido láctico > 1.5%). La adición del inóculo de BPAL mejoró el proceso de fermentación. En resumen, las mezclas conteniendo concentrado comercial para cerdos e hidratado con leche decomisada es la mejor alternativa para desarrollar dietas líquidos para cerdos recién destetados. La molienda y la adición de inoculo de BPAL mejoró el proceso fermentativo. 30 Introduction Disposal of liquid by-products generated during manufacturing processes in the pharmaceutical and food industries represents an increase in operating costs and environmental pollution for the island. SynerMax or Streptomyces soluble concentrate is an enzyme-treated, nutrient rich, liquid, co-product from Abbott Laboratories’ fermentation manufacturing which uses stringently pre-tested edible–grade soy-based ingredients. When blended into livestock diets, it provides a unique source of digestible proteins, lipids, carbohydrates, minerals, vitamins and unidentified response factors. However, more research is needed to prove its potential use in livestock diets. Waste water resulting from the caramel production is another industrial by-product that has been added in growing pigs’ diets as an energy source without affecting animal performance (León, 2002; Jiménez, 2003). However, and similar to Synermax, more experimental data are needed for its optimal inclusion in animal diets. Milk whey is a liquid by-product of cheese production consisting mostly of water, lactose, minerals and a small amount of the more soluble protein fractions that has been used in animal diets with variable success; but similar to discarded milk (milk that does not meet minimum standards form human consumption) it is presently dumped in wastes lagoons. Recycling of nutrients form these liquid organic wastes into animal diets represents an alternative to reduce costs of production and environmental pollution. In the feeding management of postweaning pigs, the use of fermented liquid diets utilizing certain agro-industrial by-products has been evaluated with great success, increasing animal performance and health (Scholter, 2001). However, there is little information regarding the use of local liquid agro-industrial by-products to develop a liquid diet for pigs. Objective To determine the fermentation characteristics of a commercial weaning pig concentrate mixed with liquid organic wastes resulting from the pharmaceutical, beverages, and food producing industries. Materials and Methods The study was conducted in the Animal Nutrition Laboratory, University of Puerto Rico, Mayagüez Campus. A commercial pig concentrate (CPC) was mixed with each of four liquid industrial organic wastes. By-products evaluated were SynerMax (SM), waste water from a caramel plant (WW), milk whey (MW) and discarded milk (DM). A mixture of deionized water (DW) CPC was used as a control treatment. The physical form of the CPC (pelleted, CPCP or 31 ground, CPCG; 1 mm screen) and the use of a lactic acid-producing bacterial inoculant (LAPBI) as microbial starter applied at 106 cfu/g or not (NLAPRB) were also evaluated. Mixtures evaluated include 1) SM-CPCP-NLAPBI, 2) WWCP-CPCP-NLAPBI, 3) MW-CPCP-NLAPBI, 4) DWCPCP-NLAPBI, 5) DW-CPCG-NLAPBI, 6) DW-CPCG-LAPBI, 7) DM-CPCG-NLAPBI, and 8) DMCPCG-LAPBI. The CPC was mixed with the liquid wastes in 2:1 proportions (w/w). To determine the fermentability of the different mixtures, triplicate samples from each treatment were placed into six hermetic digesters (1,000 ml capacity), shown in Fig. 1, and kept at ambient temperature (27-30°C). Samples (50 g) were taken from each digester at 0, 12, 24, 48, 72 and 96 hours and analyzed for pH and organic acids. For pH determination, 50 g of the mixture were placed into 450 ml of distilled water (w/v) and homogenized for 5 min with a stomacher apparatus. Homogenates were strained through eight layers of cheesecloth and analyzed with a pH meter fitted with a combination electrode that was standardized from pH 4 to 7 using commercial buffers. Fermentation products (lactic, acetic, propionic, and butyric acids) were quantified in a commercial certified laboratory. Data were analyzed as a completely randomized design with a 8 (mixtures) by 6 (fermentation periods 0, 12, 24, 48, 72, and 96 h) factorial arrangement of treatments using the General Lineal Model subroutine of SAS (1990). The Bonferroni t-test was be use for separation of means. Results and Discussion Information regarding the initial chemical composition of the liquid organic wastes tested in this experiment obtained from various sources is presented in Table 1. An acid pH and a lactic acid content greater than 2%, is characteristics of the by-product from the pharmaceutical industry (SynerMax). The waste water from the caramel processing plant is less acidic than SM, but also has a greater lactic acid content (1.4 %) than typical liquid organic wastes from the food industry. During the fermentation for all mixtures production of propionic, and butyric acids was minimal, reaching concentrations lower than 0.02%. Likewise, during 96 hours of fermentation no changes (P <.05) in pH and concentrations of lactic and acetic acids was observed in the commercial pig concentrate mixed with SM and WW during 96 hours (Mixtures 1 and 2, table 2). The final acidity and organic acids content observed in these mixtures was more related to the initial characteristics of the liquid wastes than to the fermentation process. The initial composition of these liquid wastes (SM and WW) might have influenced negatively the microbial population needed to ferment the commercial pig concentrate. It is well know that low pH, high 32 liquid density, high concentration of minerals (e.g. S, Na), and organic acids affect the activity of desirable bacteria associated with the fermentation process. Table 1. Chemical composition of liquid organic wastes evaluated Item (%) Dry Matter Organic Matter2 Inorganic Matter2 Crude Protein2 Crude Fat2 Lactose pH Lactic acid Acetic acid Propionic acid Butyric acid 1 SynerMax Wastewater from a caramel plant Milk Whey1 Discarted Milk1 48.7 91.6 8.4 14.5 8.4 ND 12.7 75.6 24.4 5.90 2.70 ND 4.01 99.0 .05 1.02 1.45 2.45 13.20 99.0 1.0 3.80 2.90 4.50 3.81 5.27 6.52 6.40 1.41 0.00 0.00 0.00 ND ND ND ND ND ND ND ND 2.04 1.00 0.27 0.00 As fed, ND = Not determined In CPC pelleted and fermented with milk whey (mixture 3, table 2) the pH decreased (P< .05) and lactic acid and acetic acid contents increased (P < .05) as length of fermentation increased. However, final pH was higher and lactate concentration of the mixture was lower than the expected values indicative of well fermented feedstuffs. Grinding of the CPC seemed to influence positively the fermentation process. Grounded CPC mixed with deionized water (mixture 5) had lower (P<.05) pH and higher (P<.05) lactic acid concentration than pelletedCPC fermented with DW (mixture 4) after 96 of fermentation. Addition of lactic acid-producing bacterial inoculum also improved the fermentation process in grounded CPC fermented with water (mixture 6) as evidenced by changes in pH and lactate concentrations. Similarly to mixtures containing MW and DW, pH decreased (P<.05) and lactic acid concentrations increased (P<.05) in grounded CPC fermented with discarded milk (mixture 7). However, this mixture showed a lactic acid concentration greater than 1.5% and a final pH value lower than the expected value (< 4.5). The fermentation characteristics of the mixture also showed a slightly improvement with the addition of the microbial starter (mixture 8). Conclusion The mixtures containing ground commercial weaning pig concentrate hydrated with discarded milk and aided or not by the LAPBI seem to be the best alternative among those tested to develop a liquid diet for early weaning pigs. Grinding the diet and the use of a suitable microbial culture improved the fermentation process. 33 Table 2. Characteristics of liquid organic wastes fermented with a commercial pig concentrate during 96 hours Mixture Physical Form1 P LAPBI2 1 SM:CC 2 WW:CC 3 MW:CC P No 4 DW:CC P 5 DW:CC 6 7 8 Components pH Fermentation Product (g/100g) Lactic Acetic 0 12 24 48 72 96 5.38 5.67 5.73 5.77 5.71 5.77 0 12 24 48 72 96 4.46 4.50 4.50 4.45 4.40 4.42 0.43 0.59 0.56 0.44 0.73 0.52 0.06 0.09 0.08 0.06 0.11 0.11 0 12 24 48 72 96 6.16a 6.17a 6.14a 5.94b 5.73c 5.30d 0.05c 0.10c 0.13bc 0.10c 0.17b 0.27a 0.01b 0.01b 0.02b 0.09a 0.12a 0.09a No 0 12 24 48 72 96 6.35a 6.13b 6.14b 5.77c 5.33c 4.77d 0.07c 0.18c 0.07c 0.19c 0.32b 0.70a 0.00 0.00 0.01 0.01 0.09 0.12 G No 0 12 24 48 72 96 6.19a 6.25a 6.15ab 6.10b 5.69c 4.61d 0.08c 0.15c 0.17c 0.21bc 0.35bc 0.92a 0.05c 0.06c 0.19a 0.26a 0.11b 0.14b DW:CC G Yes 0 12 24 48 72 96 6.39a 6.31a 6.34a 5.90b 5.49d 4.57e 0.08d 0.29c 0.38c 0.60b 1.02a 1.08a 0.01 0.01 0.01 0.02 0.06 0.09 DM:CC G No 0 12 24 48 72 96 6.44a 6.30b 6.24b 5.61c 4.70d 4.44e 0.09d 0.11d 0.66c 0.72c 1.22b 2.89a 0.01b 0.01b 0.02b 0.16a 0.20a 0.23a DM:CC G Yes 0 12 24 48 72 96 6.45a 6.28b 6.24b 5.47c 4.79d 4.42e 0.09d 0.10d 0.09d 0.73c 2.10b 3.03a 0.01b 0.01b 0.01b 0.03b 0.18a 0.23a < 4.5 < 1.5 >.80 P No Period (h) No Expected Final Value 1 P = Pelleted; G = Grounded LABPI = Lactic acid-producing bacterial inoculant a,b,c,d,e Means with unlike within mixture superscripts differ (P < .05) 2 34 1.36 1.30 1.51 1.44 1.39 1.50 0.21 0.19 0.23 0.32 0.29 0.33 Fig. 1. Anaerobic digestors fermenting liquid organic wastes with a commercial early pig concentrate Literatured Cited Jiménez, E. 2003. Use of Waste Waters from a Caramel Producing Plant as a Supplement in the Diet of Early Weaning and Finishing Pigs. M.S., Department of Animal Industry, University of Puerto Rico, Mayagüez Campus. 57 pp. León, F.J., R. Sánchez, C.S. Santana and A. Rodríguez. 2003. Waste Water from a Caramel Industry as a Partial Substitute in Diets for Pigs. Journal of Agriculture of the Unversity of Puerto Rico. 87 (1-2): 87-90. SAS/STAT. 1990. SAS User’s Guide (Release 6.12). SAS Inst., Inc., Cary, NC. Scholten, R.H.J. 2001. Fermentation of liquid diets for pigs. Ph.D. Dissertation, Wageningen Institute of Animal Science, Department of Animal Nutrition. Wageningen University, The Netherlands. 35 Fermentation characteristics and dry matter disappearance of grass hay, rhizome peanut and by products silages Karla M. Tous, Teodoro Ruiz and Héctor L. Díaz University of Puerto Rico, Mayagüez Campus, Mayagüez, Puerto Rico 00680 Abstract In situ dry matter disappearance (ISDMD) was determined on four feeds in both the fermented and unfermented state: residues of tilapia (Oreochromis niloticus) fillet production, pineapple processing residues (Ananas camosus), rhizome perennial peanut hay (Arachis glabrata) and stargrass (Cynodon nlemfuensis) hay, for which two fistulated Holstein cows fed grass hay were used. Triplicate samples from each feed, in Dacron bags were intraruminally incubated for 48 hrs, and then analyzed for DM disappearance. Data were analyzed using the general linear model of SAS® and Bonferroni test for separation of means. Results showed significant differences in dry matter content of the fermented feeds, rhizome peanut being highest (35.61%) and pineapple residue lowest (10.35%), (P<.05). Fermented stargrass showed the highest pH (5.61) and pineapple residues the lowest (4.12) (P<.05). In recovery of humid matter, peanut hay (99.51%) was superior to tilapia silage (95.12%) but not significantly different from stargrass (97.85%) and pineapple residues (96.21%). In concentration of lactic acid, silages of tilapia (2.35%) and pineapple residue silage (1.55%) were significantly different from stargrass (0.59%) and rhizome peanut silages (0.55%), (P<.05). Pinneaple silage (1.33%) and stargrass silage (0.63%) were the only fermented materials that showed significant concentrations of acetic acid (P<.05). Only small concentrations of propionic, iso-butyric and butyric acid were detected (P>.05). Crude protein content was highest in tilapia residues (39.3%), and lowest in rhizome perennial peanut (10.41%). Ensiling increased the ruminal digestibility of the CP at 24 hours of incubation in rhizome peanut, stargrass and tilapia compared to the fresh materials (55.7 vs. 66.3%). Ensiling also reduced the ruminally undegradable protein of stargrass (45.6 vs. 33.1%) and tilapia (54.3 vs. 39.9%). Resumen La desaparición de materia seca in situ (ISDMD) fue determinada en 4 alimentos en estado fermentado y no fermentado: residuos de la producción de filete de tilapia; (Oreochromis niloticus), residuos del procesamiento de piña (Ananas camosus), heno de maní forrajero (Arachis glabrata) y de hierba estrella (Cynodon nlemfuensis), para la cual se usaron 2 vacas Holstein fistuladas, alimentadas con dieta de heno de gramínea. Se colocaron 2 g de maní forrajero, piña y estrella ó 5 g de tilapia en bolsas Dacrón. Muestras triplicadas de cada alimento fueron encubadas en el rumen por 48h y luego analizadas para desaparición de MS. Los datos fueron analizados utilizando el modelo general lineal de SAS® y prueba Bonferroni. Los resultados indicaron diferencias significativas en contenido de materia seca en los alimentos fermentados, siendo maní forrajero (35.61%) el mayor y residuos de piña (10.35%) el menor (P<.05). La estrella fermentada mostró el valor más alto en pH (5.61) y los residuos de piña el más bajo (4.12), (P<.05). En recuperación de materia húmeda, heno de maní (99.51%) superó el ensilaje de tilapia (95.12%) pero no difirió significativamente de estrella (97.85%) y residuos de piña (96.21%). El contenido de proteína cruda fue más alto en residuos de tilapia, y más bajo en maní forrajero (39.3 y 10.41%). En concentración de ácido láctico los ensilajes de tilapia (2.35%) y residuos de piña (1.55%) difirieron significativamente de los de estrella (0.59%) y de maní (0.55%). Los ensilajes de piña (1.33%) y de estrella (0.63%) fueron los únicos materiales fermentados que mostraron concentraciones significativas de ácido acético (P<.05). No se detectaron concentraciones significativas de los ácidos propiónico, iso-butírico y butírico (P>.05). El ensilamiento aumentó la digestibilidad ruminal de la proteína cruda a las 24 horas de incubación en maní forrajero, estrella y residuos de tilapia relativo a los materiales frescos (55.7 vs. 66.3%); también redujó la fracción de proteína no degradable en el rumen de estrella (45.6 vs. 33.1%) y tilapia (54.3 vs. 39.9%). 36 Introduction One of the most important and limiting aspects to consider in ruminant livestock production is the type and quality of feed provided. Use of high quality feeds can translate into higher productions of milk and meat. This is especially important in the tropics, were ruminants experience environmental conditions that limit their abilities for feed consumption and growth. The dependence on low quality tropical forages as ruminant feeds makes it difficult to achieve the genetic potential of high producing animals. Silages from legume forages like rhizome perennial peanut, constitute a viable alternative to provide animals the high quality feeds they require. These forages are characterized by lower concentrations of fiber, and higher concentrations of degradable nutrients, particularly in crude protein (CP), relative to grass hay. Grass hay tends to present higher concentrations of fiber and lower rates of digestibility. Perennial peanut is a high quality, persistent legume that adapts easily to tropical and subtropical environments (Staples et al., 1997). Silages made from organic residues, such as those resulting from processing of tilapia, are quite high in protein content, which makes them a better carrier of this nutrient than forage silages. Fish silages can be an important protein supplement, but their efficiency depends on the durability of their nutritional value, after conservation by anaerobic fermentation, and the freshness of the fish byproducts used (Hussein et al., 1991). When working with organic wastes from tilapia and other types of fish it, is of great importance to preserve the protein, as these products are mainly suppliers there of. The in situ method has had great acceptance among investigators and is commonly used to estimate the degradability of feed components, like dry matter (DM) and CP (Olaisen et al., 2003). Values determined in situ are generally good indicators of the nutritional value of feeds preserved by anaerobic fermentation. Objectives Evaluate the effects of anaerobic fermentation of organic wastes from tilapia, pineapple processing and two tropical forages; one grass and one legume, on chemical composition, recovery of ensiled matter and DM and CP degradability. Materials and Methods Stargrass hay (Cynodon nlemfluensis), residues from processed pineapple (Ananas camosus), wastes from tilapia (Oreochromis niloticus) fillet production and rhizome perennial peanut hay (Arachis glabrata) where cut into 5.08 cm. pieces. The tilapia waste only was mixed with 30% 37 molasses. The feeds were subjected to anaerobic fermentation for a minimum of 21 days, in PVC silos in the laboratory. Two samples of each fresh material and three samples of each resulting silage were analyzed. The in situ method was used to determine DM and CP degradability. Two fistulated Holstein cows, fed a grass hay diet were used. The determination involved placing 2g of stargrass hay, pineapple organic wastes and peanut or 5g of tilapia organic wastes in nylon bags (Dacron). Triplicate samples from each feed were incubated intraruminally (Fig. 1,2 and 3) for 0, 3, 6, 12, 24 y 48 h, and then analyzed for DM disappearance. After the incubation time lapsed, the bags were removed from the rumen, rinsed in water (Fig. 4) and placed on ice for 15 min. to stop further bacterial fermentation (Fig. 5). The bags were placed in a washing machine, during one washing cycle (Fig. 6). Then the bags were placed in a convection oven, at 65˚C for 48h to dry. Dry bags were weighed, to determine DM disappearance. CP content from the residues at each incubation time was determined using the Kheldajl method. This final step was needed to determine CP degradability. Data were analyzed using the general lineal model of SAS® and Bonferroni test of mean separation. Results and Discussion Table 1 presents means of DM and CP content, proportion of humid matter recovery and in situ DM degradability of the silages. Processed pineapple silage was the lowest in DM content, resulting from its high proportion of residual juice. Tilapia silage showed the second highest DM content, which resulted from mixing the fish residue with sugarcane molasses. Proportion of humid matter recovered as silage was high for all feeds, indicating a good fermentation. CP content on processed pineapple residue was similar to that of the two tropical forage silages. Atypically the perennial peanut was lower in CP than stargrass in this study. Tilapia silage showed the highest CP content by a wide margen, establishing it as a potential protein supplement in ruminant diets. Pineapple residue silage was outstanding in ruminal degradability; tilapia silage in second place, was higher than the two tropical forages, but not significantly so relative to perennial peanut, which had a higher DM degradability than stargrass. Silages from these two organic wastes clearly shows a higher nutritional value in terms of digestibility than tropical forages, which establishes them, especially processed pineapple, as possible energy supplements in ruminant diets, whereas tilapia silage is superior as a protein supplement. 38 Fig.1) Preparation for sample placement Fig.2) Samples for one incubation time to be placed intraruminally Fig.3) Intraruminal sample placement 39 Fig.4) Rinsing of all incubated samples after removal from the rumen Fig.5) Ice bath to stop further bacterial fermentation Fig.6) Samples in washing machine during 1 washing cycle 40 Table 1. Dry matter content (DM), recovered humid matter (RM) and ruminal degradability of DM of two tropical forage silages and two fermented organic wastes. Silage DM (%) RM (%) c 97.85ab Stargrass Rhizome perennial peanut 24.285 36.11a 99.51a Pineapple 11.181d 96.21bc Tilapia 30.162b EE Crude Protein on dry base (%) 12.58 1.466 Degradability of DM at 48h (%) 50.314c 10.41 58.383b 10.71 74.533a 95.12c 39.3 64.066b 1.431 14.07 0.233 Means with the same letter on the same column do not present significant differences. DM- Dry matter RM- Recovered matter EE-error mean square Fermentation characteristics of these silages are shown in Table 2. Pineapple waste silage had the lowest pH, while tilapia silage showed a small but significant difference, relative to the two forage silages, as did peanut silage, relative to stargrass. The higher quality of tilapia and processed pineapple silage is indicated by their lactic acid content and also acetic acid content in the case of pineapple silage, when compared to the legume and grass silages. Even though there were differences in DM ruminal degradability for the various silages, no significant difference was established between the fresh and corresponding ensiled feeds. Mean values were 60.7% and 62.5%, respectively (Figure 7). Thus the ensiled materials mantained the digestibilty level that were present in the fresh state. Table 2. Fermentation characteristics of organic waste silages and silage from tropical forages evaluated. Sample pH Lactic acid (%) Acetic acid (%) Propionic acid (%) Iso-butyric Acid (%) StargrassEstrella Rhizome perennial peanut 5.608a 0.59b 0.632ab 0.013a 0.0008b 5.465b 0.55b 0.402b 0b 0b d ab a Pineapple 4.118 1.55 1.334 0.114 0.021a Tilapia 5.306c 2.34a 0.366b 0.026b 0.006ab EE 0.00433 0.355 0.164 0.00102 0.000072 Means with the same letter on the same column do not present significant differences. EE-error mean square 41 b Figure 7. Effect of ensiling on the 48 hr. in situ degradability of pineapple, tilapia, perennial peanut and stargrass. 0.625 0.625 0.62 0.615 Degradability 48h (%) 0.607 Fermented Unfermented 0.61 0.605 0.6 0.595 Forage Type As a result of fermentation, peanut, stragrass and tilapia increased their ruminal protein digestibility level at 24 hr of incubation and their proportion of soluble protein (Table 3), contrasting with pineapple, which showed opposite tendencies. The fermentation process resulted in a reduction in the proportion of ruminal non degradable protein (RUP), in stragrass and tilapia wastes, which were the only two feeds from which data were obtained on this criterion. Table 3. Determination of soluble CP fraction (CP), in situ CP digestibility at 24 hours of incubation and ruminally un-degradable protein (RUP), of organic wastes from tilapia, pineapple and tropical forages, fresh and ensiled. Soluble Fraction 24h Digestible Sample (%CP) incubation (%CP) RUP Rhizome perennial peanut Fresh, Ensiled, Stargrass Fresh, Ensiled, Tilapia wastes Fresh, Ensiled, Pineapple waste Fresh, Ensiled, 14.0 46.6 56.7 63.0 - 36.3 56.0 57.8 69.9 45.6 33.1 21.8 28.6 52.8 66.1 54.3 39.9 70.4 56.7 84.5 70.6 - 42 These experimental results indicate that anaerobic fermentation is an effective method of preserving some organic wastes, and of improving their nutritive value and ruminal digestibility. The biggest negative effect occurred in the increase in ruminal CP degradability of silages of the two forages and tilapia. BY contrast the CP solubility and ruminal degradability of the pineapple, waste were higher in the fresh material than in the ensiled product. A high ruminal degradability of protein is undesirable in feeds with a potential to supply high quality protein at the intestinal level, as in the case of tilapia waste. Literature Cited Hussein,H.S and R.M. Jordan, 1991. Fish meal as a protein supplement in ruminant diets: a review. J. Anim. Sci. 69:2147-2156. Olaisen,V., T. Medjell, H. Volden and N. Nesse, 2003. Simplified in situ method for estimating ruminal dry matter and protein degradability of concentrates. J. Anim. Sci. 81:520-528. Staples,C.R., S.M. Emanuele and G.M. Prine, 1997. Intake and nutritive value of florigraze rhizoma peanut silage for lactating dairy cows. J. Anim. Sci. 80:541-549. 43 Use of Waste Water from a Caramel Producing Plant as a Supplement in Diets of Weaning Pigs María del Pilar Díaz Cabán, Carmen S. Santana Nieves and Abner A. Rodríguez Department of Animal Industry, University of Puerto Rico, Mayagϋez Campus Abstract Disposal of waste water represents an increase in operational costs for the caramel producing operation in Puerto Rico and environmental pollution for the Island. Previous studies showed that it is possible to improve weaning pigs’ performance by the addition of this waste water to the diet (Jiménez, 2003). In this experiment, a four week trial was conducted to evaluate the addition to the diet of 0% (control) and 10% waste water from a caramel producing plant (WWCPP) on swine performance at weaning. Sixteen Landrace shoats of 21 + 2 days of age with an average live weight of 6 kg were used in a completely randomized design (n=4) with a boar and a gilt per pen. Feeding was on an 8% of bodyweight daily basis. Feed intake, weight gain and feed efficiency were not affected (P>0.05) by the addition of 10% WWCPP to the diet. Animal health status was not affected either. In the present case performance at weaning was not improved by the dietary addition of 10% of WWCPP, as occurred in previous studies with levels up to 7.5% WWCPP. Resumen Las aguas residuales de una planta productora de caramelo (ARPPC) requieren un gasto para su disposición y son consideradas un contaminante ambiental para la Isla. Estudios previos han demostrado que añadir estas aguas en la dieta de cerdos al destete en niveles de hasta 7.5%, mejora el consumo de alimento, la ganancia en peso y la eficiencia de estos animales (Jiménez, 2003). En el presente estudio dieciséis cerdos Landrace de 21±2 días de edad, con un peso vivo promedio de 6 kg, fueron distribuidos al azar a 8 jaulas (un macho y una hembra por jaula) para evaluar su desempeño al añadir a la dieta 0 ó 10% de estas aguas durante cuatro semanas. Los cerdos fueron alimentados en base al 8% de su peso vivo. El consumo de alimento, la ganancia en peso y la eficiencia alimenticia no fueron afectadas significativamente con la adición de 10% de ARPPC (P>0.05). Tampoco se observaron efectos negativos sobre la salud de los animales. Basándonos en los resultados obtenidos en este estudio podemos inferir que la adición de 10% de ARPPC no mejoró el desempeño de cerdos al destete, diferencia de los resultados de estudios previos con niveles menores de ARPPC. 44 Introduction Swine producers have decreased the age at weaning in order to increase the number of pigs weaned per sow annually and thus improve profitability (Kerr et al. 1998). The early weaned pigs require highly digestible diets, including high quality protein ingredients, which makes the diets more expensive (Richert et al. 1996). In PR swine producers do not follow proper management practices for successful early weaning. This is, in part, because of the lack of proper physical facilities and feed. The acquisition of complex diets (for pigs under 21 days of age) represents a problem in PR because there is no local production of this kind of diet and the only ones available are too expensive, to be attractive to swine producers. Therefore, there is a need to identify other low-cost ingredients, which can be easily added to the diets without compromising animal performance, and help to reduce production costs. On the other hand, in PR there is an environmental pollution problem due to waste disposal that has been increasing over the years. This has stimulated interest in searching for new alternatives that might reduce the problem. The waste waters from a caramel producing plant (WWCPP) are considered environmental pollutants. Recent studies with the use of different percentages of these waste waters (Léon et al., 2003; Jiménez, 2003) in the diets of weaning pigs, have reported improved performance at the levels evaluated (up to 7.5% addition). These previous results suggested evaluating higher levels of WWCPP in the diets of early weaned pigs. Objective To evaluate the performance of weaning pigs receiving a diet containing 10% of waste water from a caramel producing plant. Materials and Methods Sixteen Landrace shoats from two different litters, averaging 21±2 days of age, and 6kg body weight, were distributed among eight pens (one male and one female per pen) at the Department of Animal Industry Swine Farm located in Lajas, PR. Pigs were fed a commercial weaning diet, at the rate of 8% of their bodyweight daily, with the addition of 0 or 10% of WWCPP. These residual waters were obtained from the Coca-Cola Company plant located in Gurabo, PR and were mixed together with the dry feed. The pigs were weighted once a week and their feed intake was registered. The animals were observed periodically for the presence of diarrhea or any visible change in their health status. 45 The variables feed intake, weight gain and feed efficiency were analyzed as a completely randomized design using a lineal model by SAS statistical package (1990) with the initial bodyweight per pen as a covariable. Results and Discussion The addition of 10% of WWCPP did not significantly affect (P>0.05) productive performance in this trial (Figures 1 and 2). Feed intake and weight gain were similar between the control (0% of WWCPP) and the supplemented (10% of WWCPP) group. The control group showed an advantage in feed efficiency by a margen of 0.08 kg weight gain/kg intake (Figure 3), but this difference was not significant (P>0.05). These results differ from those obtained by Jiménez (2003), in which the WWCPP supplemented pigs showed greater feed intake, weight gain, and feed efficiency compared with the control group (P≤0.05). However, the levels of WWCPP evaluated in that study were lower than the level evaluated in the present trial (up to 7.5% vs. 10%, respectively). The covariable was statistically significant (P≤0.05) for feed intake, but not for weight gain or feed efficiency (P>0.05). Logically heavier pigs are expected to consume more feed (National Research Council, 1987). Neither diarrhea nor any other health problems were observed in the Kg pigs supplemented with 10% of WWCPP. 1.2 7.7 ± .25 5.9 + .38 Kg 9 8 7 6 5 4 3 2 1 0 7.4 + .25 1.10 + .04 1 1.06 + .04 .85 + .05 .74 + .05 0.8 5.1 + .38 0.6 0.4 0.2 0 P>0.05 P>0.05 0 P>0.05 Levels of WWCPP (%) Weekly Intake 10 0 10 Levels of WWCPP (%) Feed Intake Weekly Gain Fig. 1. Weekly feed consumption and weight Weight gain Fig. 2. Daily feed consumption and weight gain as gain as affected by supplementation with WWCPP. Event gain/feed intake) was higher affected by supplementation with WWCPP. 46 0.77 + .05 Feed Efficiency 0.78 0.76 0.74 0.72 0.69 + .05 0.7 Fig. 3. Feed efficiency as a affected by 0.68 supplementation with WWCPP. 0.66 0.64 0 10 Levels of WWCPP (%) P>0.05 Conclusion In this study no significant effects on the performance of weaning pigs resulted from supplementation with 10% of waste water from a caramel producing plant. Feed intake, weight gain and feed efficiency were not statistically affected as compared to the control. Although, considering previous results, no additional benefit of increasing the level of WWCPP from 7.5 to 10% in the diet of weaning pigs was found, this industrial byproduct could be useful to substitute for part of the imported ingredients used in swine feeding in Puerto Rico, depending on relative costs. Collecting orts. Weighing the pigs. 47 Literature Cited Jiménez, E. 2003. Use of Waste Waters from a Caramel Producing Plant as a Supplement in the Diet of Early Weaning and Finishing Pigs. Masters Thesis, Department of Animal Industry, University of Puerto Rico, Mayagüez Campus. 57 pp. Kerr C., R.D. Goodband, J.W. Smith, R.E. Musser, J.R. Bergstrom, W.B. Nessmith, M.D. Tokach and J.L. Nelssen. 1998. Evaluation of Potato Proteins on the Growth Performance of EarlyWeaned Pigs. Journal of Animal Science. 76: 3024-3033. León, F.J., R. Sánchez, C.S. Santana and A. Rodríguez. 2003. Waste Water from a Caramel Industry as a Partial Substitute in Diets for Pigs. Journal of Agriculture of the Unversity of Puerto Rico. 87 (1-2): 87-90. National Research Council (NRC). 1987. Predicting Feed Intake of Food-Producing Animals. National Academy Press, Washington D.C. pp. 25-41. Richert B.T., K.R. Cera, A.P. Schinckel, L.K. Clark and J.J. Turek. 1996. Effect of Nursery Diet Complexity and Weaning Age on Pig Growth Performance and Health Status. Purdue Swine Day. 1-4. SAS/STAT. 1990. SAS User’s Guide (Release 6.12). SAS Inst., Inc., Cary, NC. 48 The role of circulating insulin-like growth factor binding proteins (IGFBP) in the growth of pigs supplemented with a unique caramel wastewater (CPWW) in the diet María de los Milagros Soltero, Melvin Pagán, María del Pilar Díaz and Carmen Santana University of Puerto Rico, Mayagüez Campus Abstract Over the past few decades, a world wide effort for the control of industrial pollution has pinpointed several areas on which research is needed to develop alternatives for the disposal of polluting agents. In the case of the caramel industry, effective usage of the secondary waste-water products (CPWW) generated would help to relieve this situation. Previous studies have shown that the addition of levels up to 7.5% of this waste-water to the diet of weaning pigs improves their performance (Jimenez, 2003). At the same time, the circulating insulin-like growth factor binding proteins (IGFBP) function to regulate the endocrine actions of insulin-like growth factor-I (IGF-I) and recent in vitro and in vivo findings suggest that IGFBP also function independently of the IGF-I as growth modulators. Moreover, growth hormone (GH) is responsible of the regulation of the overall effect of IGF and IGFBP. With these considerations in mind, an experiment was conducted to evaluate the expression of circulating IGFBP, IGF-I and GH in response to a 10% inclusion of CPWW in weaning pig diets to assess associations between those growth related proteins and feed consumption, daily weight gain, and feed efficiency. Sixteen purebred Landrace pigs were randomly distributed among 8 pens (a gilt and boar per pen) and assigned one of two treatments: 0% (control) and 10% inclusion of CPWW. During five consecutive weeks live weight and feed consumption were recorded. Blood samples were drawn by jugular venipuncture during the first, second, and third week of the experiment and serum levels of IGF-I, IGFBP-III, IGFBP-II, GH were determined by radioimmunoassay (RIA), immunoradiometric assay (IRMA) and enzyme-linked immunosorbent assay (ELISA), respectively. Serum IGF-I levels were higher in control animals (P < 0.05) and increased from d 14 to d 28 of the experimental period (P < 0.05). Weekly increases were observed for IGFBP-III (P < 0.05) and IGFBP-II circulating levels decreased from d 14 to d 28 of the postweaning test period. Simple correlation analysis revealed that there was a positive association between circulating levels of IGF-I and IGFBP-III (r = 0.88; P < 0.0001). However, the opposite was observed between these two and IGFBP-II (r = -0.84, P < 0.0001; r = -0.67, P < 0.0025, respectively). Levels of GH did not show any significant change between treatments, weeks or sexes (P > 0.05). The changes observed in circulating levels of IGF-I, IGFBP-III and IGFBP-II may be associated with weekly increases in feed consumption and weight gain that occurred during the entire experimental period (P < 0.05). Resumen A través de las pasadas décadas, un esfuerzo a nivel mundial ha señalado varias áreas en donde se debe realizar investigación con el propósito de desarrollar posibles alternativas para la disposición de agentes contaminantes. En el caso de la industria del caramelo, el uso efectivo de las aguas residuales (CPWW) generadas ayudaría a aliviar esta situación. Estudios previos han demostrado que la adición de estas aguas de desecho hasta niveles de 7.5% a la dieta de cerdos post-destete mejora su desempeño (Jiménez, sin publicar). Al mismo tiempo, las proteínas de enlace del factor de crecimiento similar a insulina (IGFBP) en el suero sanguíneo funcionan para regular las acciones endocrinas del factor I de crecimiento parecido a la insulina (IGF-I). Descubrimientos recientes in vitro e in vivo sugieren que los IGFBP también funcionan independientemente del IGF-I como moduladores del crecimiento. Mas aún, la hormona de crecimiento (GH) es responsable de la regulación del efecto conjunto de ambos IGF-I y IGFBP. Con esto en mente se realizó un experimento para determinar si la inclusión de un 10% de CPWW en la dieta de cerdos post-destete resulta en cambios en los niveles de IGFBP (II y III), IGF-I y GH en la sangre y por ende en diferencias en crecimiento, consumo de alimento, ganancia de peso diaria y eficiencia de conversión. Dieciséis cerdos de raza Landrace fueron distribuidos al azar a 8 jaulas (una cerda y un cerdo por jaula) y asignados a una de dos tratamientos: 0% (control) y 10% de inclusión de CPWW. Durante cinco semanas consecutivas se registró el peso vivo y el consumo de alimento de los animales. Se colectaron muestras de sangre a través de sangrado yugular durante la primera, segunda y tercera semana del experimento y los niveles de IGF-I, IGFBP-III, IGFBP-II en el suero fueron 49 determinados mediante radioimmunoensayo (RIA), ensayo immunoradiométrico (IRMA) y ensayo inmunosorbente ligado a una enzima (ELISA), respectivamente. Los niveles de IGF-I fueron más altos para los animales control (P < 0.05) y aumentaron del d 14 al d 28 del periodo post-destete (P < 0.05). Se observó un aumento semanal en los niveles de IGFBP-III (P < 0.05) mientras que, los niveles de IGFBP-II disminuyeron a partir del d 14 al d 28 (P < 0.05). Análisis de correlación simple reveló que existe una asociación positiva entre los niveles de IGF-I y IGFBP-III circulando en la sangre (r = 0.88; P < 0.0001). Sin embargo, se observó un efecto opuesto entre estos y IGFBP-II (r = -0.84, P < 0.0001; r = -0.67, P < 0.0025, respectivamente). No se observó efecto de tratamiento, semana o sexo sobre los niveles de GH (P > 0.05). Los cambios observados en los niveles sanguineos de IGF-I, IGFBP-III y IGFBP-II pueden ser responsables de los aumentos semanales en consumo de alimento y peso vivo que ocurrieron durante todo el periodo experimental (P < 0.05). Introduction Production of meat is almost entirely dependent on animal growth. However, not all aspects of growth are understood, particularly the mechanisms involved in initiation of growth, regulation of growth rate, and termination of growth at maturity (Hedrick et al., 1994). The Somatomedin hypothesis originated in early efforts to understand how somatic growth was regulated by factors secreted by the pituitary (Le Roith et al., 2001). The hormonal regulation of growth is multi-factorial and a group of proteins known to significantly affect animal growth and metabolism is the insulin-like growth factor (IGF) system. The IGF system (IGF-I, IGF-II, IGF cell surface receptors and insulin-like growth factor binding proteins) has been implicated as being involved in many biological processes of relevance to livestock production systems. These include pre- and postnatal growth, lactation, reproduction and the immune function. The IGF system plays an important physiological role in the growth and development of mammals by acting locally in specific organs or systemically through circulating IGF-I (Werner et al., 1994). The actions of both, IGF-I and IGF–II, are mediated by specific insulin-like growth factor binding proteins (IGFBP). The postulated modes of action of these binding proteins include: IGF circulatory transport vehicles, retardation of IGF degradation, transvascular IGF movement and direct modulation of IGF actions at the target cell either by enhancing or blocking its activity (McGuire et al., 1992; Florini et al., 1996). IGFBP compete with IGF receptors for IGF binding, and as a consequence, they can affect cell growth. The IGFBP can act in an endocrine, paracrine, or autocrine fashion and recent in vitro and in vivo findings suggest that IGFBP function independently of the IGF as growth modulators (Firth and Baxter, 2002). Also involved in this whole process is the growth hormone (GH). GH simultaneously stimulates the synthesis of IGF-I and produces a microenvironment that facilitates IGF-I action through the modification of the IGFBP profile (Le Roith et al., 2001). Therefore, even though great progress has occurred in meat production and processing technologies, a basic 50 understanding of animal growth as it relates to physiology of IGFBP and their IGF independent effects has potential for improving efficiency in meat production. A 10% inclusion of CPWW may induce indirect changes in relative levels of IGFBP. If this inclusion causes a positive effect on growth, it would constitute an excellent alternative for disposal of the waste water byproduct and also benefit meat production. Objectives To evaluate the expression of circulating IGFBP in response to a 10% inclusion of caramel production waste water in weaning pig diets. To asses potential correlations between relative levels of serum IGFBP and feed efficiency, feed consumption, weight gain and growth. Materials and Methods Sixteen purebred, post-weaning, Landrace pigs were randomly assigned to 8 pens (a gilt and boar per pen) and to one of two treatments: 0% (control) and 10% inclusion of CPWW. During five consecutive weeks live weight and feed consumption were recorded; and blood was drawn by jugular venipuncture. Following collection, individual serum samples were diluted 1:4 or 1:1 with Laemmli’s Electrophoresis Buffer for the analysis of sample pools and individual samples for each week. Diluted samples (2µl of serum) were subjected to SDS-PAGE using 12% separating acrylamide gels with 4% staking gels on a Protean II XI Electrophoresis Cell (BioRad Laboratories, Hercules, CA, USA). Prestained Protein Molecular Weight Standards (12 µl) (Bio-Rad Laboratories) were used to estimate molecular weights of IGFBP species. Samples were loaded on gels, control and treatment samples from each pen alternated, and all samples were run in duplicate. Separated proteins were transferred electrophoretically onto nitrocellulose membrane using a Trans-Blot Electrophoretic Transfer Cell (Bio-Rad Laboratories). Following transfer, gels were stained with Coomasie Brillant Blue R-250 (Bio-Rad Laboratories) and membranes were stained with Ponceau S Solution (Sigma-Aldrich, Inc., St. Louis, MO, USA) to assure a complete transfer. A biotinylated IGF-I western ligand blotting protocol was tested for the determination of IGFBP levels in swine serum. Membranes were washed with TBS-1% T, blocked by incubating with TBS-0.1% T- 1% BSA, rinsed with TBS-0.1% T, and incubated with 2 µg Biotinylated IGF-I (GroPep, North Adelaide, Australia), followed by the addition of Strepavidin-HRP (Amersham Biosciences, Piscataway, NJ, USA) in TBS-0.1%T. 51 Blots were rinsed, treated with ECL Western Blotting Detection Reagents and Analysis System (Amersham Biosciences) and exposed for two minutes with Kodak BioMax Light Film (Sigma-Aldrich, Inc.). Because the validation of Biotinylated IGF-I Western Ligand Blotting could not be achieved, sample pools were made and sent to Diagnostic Systems Laboratories (Webster, TX) where they were subjected to Radioimmunoassay (RIA), to detect IGFBP-II; Enzime-Linked Immunosorbent Assay (ELISA), to detect GH; and Immunoradiometric Assay (IRMA), to detect IGF-I and IGFBP-III. A diagram of the pooling strategy is provided: Days Week Effect: C+T=♀+♂ 0 14 28 1 1 1 4 4 4 2 2 2 Sex by Treatment Effect: ♀ C ♂ T C T Treatment Effect: C (all) T (all) Total Number of Pools = 21 A factorial experimental design was used to study the effect of treatment (0 and 10% CPWW), sex (male and female), week (d 0, 14, 28 of blood collection) and the interaction between sex and treatment (GLM Procedure; SAS, 1996). The correspondent means were separated using the Bonferroni test and the degree of association between GH, IGF-I, IGFBP-III and IGFBP-II was established by Pearson Correlation Coefficients (Corr Procedure; SAS, 1996). Results and Discussion No significant differences were found between control and CPWW supplemented pigs in weight gain, feed consumption, and feed efficiency (P > 0.05, data not shown). On the contrary, weekly increases in feed consumption and weight gain were observed during the entire experimental period (Figure 1, P < 0.05). Serum IGF-I levels were higher in control animals (Figure 2, P < 0.05) and increased from d 14 to d 28 of the experimental period (Figure 3, P < 0.05). Weekly increases were observed for IGFBP-III (Figure 4, P < 0.05) and IGFBP-II circulating levels decreased from d 14 to d 28 of the postweaning test period (Figure 5, P < 52 0.05). Simple correlation analysis revealed that there was a positive association between circulating levels of IGF-I and IGFBP-III (r = 0.88; P < 0.0001). However, the opposite was observed between these two and IGFBP-II (r = -0.84, P < 0.0001; r = -0.67, P < 0.0025, respectively). Levels of GH did not show any significant change between treatments, weeks or sexes (P > 0.05, data not shown). Unlike GH, which is secreted in a pulsatile manner, IGF-I levels remain fairly constant throughout the day (Bach, 1999) and can be determined from a single blood sample (Bishop et al., 1989). At the same time, IGF-I serum concentration is associated with growth traits in many livestock species (Anderson et al., 1988; Graml et al., 1994) and may be useful as a physiological indicator in selection programs designed to improve weight and growth rate in pigs (Buonomo et al., 1987). IGF-I mediates many of the growthpromoting effects of growth hormone and regulates postnatal growth and development. However, the actions of the IGF-I and –II (IGFs) are modulated by a family of six high affinity binding proteins (IGFBP-1–6) that have been identified by molecular cloning of their cDNAs from rat and human tissues (Shimasaki and Ling, 1991). These proteins bind IGFs with an affinity equal to or greater than that of the IGF-I receptor (Rechler and Clemmons, 1998) and they can act in an endocrine, paracrine, or autocrine fashion. IGFBP-2 and -3, like IGF-I, are also responsive to growth hormone (Cohick et al., 1992; Harrell et al., 1999) and may be useful indicators of rate of gain and carcass composition in livestock. IGFBP-2 is a distinct protein whose plasma concentration is inversely related to GH (Binoux et al., 1986) whereas IGFBP-3 is a glycoprotein whose plasma concentration is directly related to GH secretory status (Baxter and Martin, 1986). In the present study no association was found between serum levels of IGFI, IGFBP-III, IGFBP-II and GH (Table 1). This may be due to the fact that a single blood sample was collected to measure GH instead of the recommended 10 hours sampling strategy for accurate determination of this specific hormone. We found that circulating levels of IGFBPII even though decreased from day 14 to d 28 of the experimental period (Figure 5), were higher than the levels of both IGF-I and IGFBP-III (Figure 3 and 4, respectively). Generally, IGFBP-III is the most abundant IGFBP species in serum and milk. It is produced mainly by nonparenchymal hepatic cells and circulates in serum, binding IGF-I or IGF-II in conjunction with an acid-labile subunit (ALS) to form a 150 kDa circulating (ternary) complex at a serum concentration of about 100 nM which increased the IGF-I half life to 15 h (Rechler and Clemmons, 1998). This is in accordance with the strong positive correlation found between these two proteins in the present study (Table 1). The precise roles of individual IGFBP are still 53 unknown, due mainly to the great complexity of their actions and their regulation, but also to the fact that the overwhelming majority of information about the IGFBP is derived for in vitro studies. IGFBP-2 appears to play a key role in myogenesis (Ernst et al., 1992; Ernst et al., 1996; Fligger et a., 1998; Gerrard et al., 1999). The level of expression of IGFBP-2 mRNA and protein was found to be high in proliferating turkey myogenic satellite cells (Ernst et al., 1996) and mouse myoblast (Ernst et al., 1992) and to decrease gradually as differentiation progressed. This has been associated with a sequestration of IGF-I by IGFBP-2, which makes that growth factor less available to the myogenic satellite cells (Fligger et al., 1998). Schneider et al. (2000) reported that the most prominent phenotype in IGFBP-2 transgenic mice was a reduction of somatic growth and that overexpression of IGFBP-3 under a ubiquitous promoter resulted in selective organomegaly. In our study, circulating levels of both IGFBP-III and IGFBP-II were much higher than the levels of IGF-I. Therefore, these two binding proteins somehow are regulating the actions of IGF-I (Table 1) and probably functioning in an IGF-I independent manner (according to serum levels, Figures 3, 4 and 5). Therefore, the changes observed in circulating levels of IGF-I, IGFBP-III and IGFBP-II may be associated with the weekly increases in feed consumption and weight gain that occurred during the entire experimental period (Figure 1, P < 0.05). d 12 c 10 c c 8 kg 6 b a b 4 a 2 0 1 2 3 Time (weeks) Feed Consumption Figure 1. 4 Weight Gain Weekly feed consumption and weight gain (Kg) of post-weaning pigs. Within each variable means lacking a common superscript letter differ (P < 0.05). 54 a 100 90 b 80 70 60 IGF-I (ng/mL) 50 40 30 20 10 0 Control Figure 2. Treatment Serum IGF-I levels of controls pigs and pigs supplemented by a 10% inclusion of CPWW during the postweaning period. Samples collected at day 0, 14 and 28 of the experimental period were pooled for control and supplemented pigs and IGF-I was determined by Immunoradiometric assay (Diagnostic Systems Laboratories, Inc.). Within each variable means lacking a common superscript letter differ (P < 0.05). b 180 160 140 120 IGF-I (ng/mL) a 100 80 a 60 40 20 0 0 14 28 Time (Days) Figure 3. Serum IGF-I levels of postweaning pigs. Samples collected at day 0, 14 and 28 of the experimental period were individually pooled and IGF-I was determined by Immunoradiometric assay (Diagnostic Systems Laboratories, Inc.). Within each variable means lacking a common superscript letter differ (P < 0.05). 55 c 300 b 250 200 a IGFBP-III (ng/mL) 150 100 50 0 0 14 28 Time (Days) Figure 4. Serum IGFBP-III levels of postweaning pigs. Samples collected at day 0, 14 and 28 of the experimental period were individually pooled and IGFBP-III was determined by Immunoradiometric assay (Diagnostic Systems Laboratories, Inc.). Within each variable means lacking a common superscript letter differ (P < 0.05). a 1200 a 1000 b 800 IGFBP-II (ng/mL) 600 400 200 0 0 14 28 Time (Days) Figure 5. Serum IGFBP-II levels of postweaning pigs. Samples collected at day 0, 14 and 28 of the experimental period were individually pooled and IGFBP-II was determined by Radioimmunoassay (Diagnostic Systems Laboratories, Inc.). Within each variable means lacking a common superscript letter differ (P < 0.05). 56 Table 1. TRAIT WEEK IGF-I Pearson Correlation Coefficients for Serum IGF-I, IGFBP-III, IGFBP-2 and GH. IGF-I 0.88 0.0001 IGFBP-III 0.92 0.0001 0.88 0.0001 IGFBP-III IGFBP-II -0.64 0.0042 -0.84 0.0001 -0.67 0.0025 GH -0.48 0.05 -0.20 0.4145 -0.34 0.1654 IGF-I = Insulin-like growth factor-I IGFBP-III = Insulin-like growth factor binding protein-III IGFBP-II = Insulin-like growth factor binding protein-II GH = Growth Hormone Conclusion Changes in circulating levels of IGF-I, IGFBP-III, and IGFBP-II observed in control pigs and pigs supplemented with a 10% inclusion of CPWW may be responsible of weekly increases in feed efficiency and weight gain that occurred during a 28 d postweaning experimental period which reaffirms that these proteins play a key role in swine growth regulation. Figure 6. Jugular Venipuncture of Control Pigs and Animals Supplemented with a 10% Inclusion of CPWW in the Diet 57 Literature Cited Anderson, P.T., W.G. Bergen, R.A. Merkel, W.J. Enright, S.A. Zinn, K.R. Refsal, and D.R. Hawkins. 1988. 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