Effect of Dietary Lipase Enzyme on Gut

Transcription

Effect of Dietary Lipase Enzyme on Gut
METABOLISM AND NUTRITION
Effect of Dietary Lipase Enzyme on Gut Morphology, Gastric Motility, and
Long-Term Performance of Broiler Chicks
W. Al-Marzooqi1 and S. Leeson2
Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
acteristics, especially feed intake. Only starter diets (0 to
21 d) were supplemented with 0, 0.375, 0.750, or 1.125%
enzyme, and each diet was represented by three replicate pens of 25 male chicks each. Subsequent diets did
not contain any enzyme. During the first 3 wk, increased
dietary concentration of lipase enzyme caused a linear
reduction of feed intake and body weight gain (P <
0.01). At 21 d the percentage weight of the liver was
significantly greater with 1.125% enzyme (P < 0.01).
However, added enzyme had no effect on 21 to 42 d or
1 to 42 d growth or feed intake (P > 0.05) or on the size
of any internal organs examined at 42 d. Pancreatic威
enzyme has previously been shown to improve fat digestion and increase diet AMEn for young chicks fed animal-vegetable blended fats. These positive effects, however, are associated with marked anorexia, and from the
present study, it seems that this effect was not related
to physical changes in gut histology or in prolonged
digesta transit time.
ABSTRACT Three experiments were conducted to test
a previously described anorexic effect of graded dietary
supplements of Pancreatic威 lipase enzyme on gut structure, gastric motility, and long-term performance of
broiler chicks. In Experiment 1, dietary Pancreatic威 enzyme was used at graded levels of 0, 0.214, 0.429, 0.643,
0.857, and 1.071% to test the effect of this enzyme on
gut structure, whereas Experiment 2 was designed to
test its effect at 0, 0.268, 0.536, 0.804, 1.071, and 1.339%
on gastric motility. The histological examination of the
small intestine and a cineradiographic study of birds
fed diets supplemented with lipase enzyme failed to
detect any difference in gut structure, and there was no
apparent adverse effect on gastric motility. Experiment
3 was conducted to test the effect of graded supplements
of Pancreatic威 enzyme on performance of 300 male
broiler chicks raised for 6 wk to determine whether the
enzyme had any long-term effect on performance char-
(Key words: lipase, fat, intestinal physiology)
2000 Poultry Science 79:956–960
and Gentle (1980) reported that intravenous injection of
cholecystokinin (CCK) depresses feed intake in chickens.
Antin et al. (1975) observed that CCK not only reduces
feed intake but also elicits satiety in rats. The Pancreatic威
enzyme used in these studies is extracted from the pancreas of pigs, and so could conceivably contain some
CCK activity. The aim of the experiments reported here
was to test the effect of Pancreatic威 enzyme on gut structure and gastric motility and to test whether this enzyme
has any lasting effect on feed intake and performance
of male broiler chicks.
INTRODUCTION
Krogdahl and Sell (1989) found that pancreatic lipase
activity was maximized 42 to 56 d after hatch. Over
the same period there was a marked improvement in
utilization of dietary tallow and animal-vegetable fat
(AV) by young birds. Noy and Sklan (1995) reported
that lipase activity increased at a slower rate than for
most other digestive enzymes. Therefore, a low level of
natural lipase production in young birds likely limits
fat digestion. However, based on the results obtained in
our previous studies (Al-Marzooqi, 1998), a clear pattern
of reduced feed intake and growth rate caused by various supplemental lipase enzymes is cause for concern
in any practical application of such supplements. Savory
MATERIALS AND METHODS
Experiment 1
Two hundred eighty-eight commercial strain male
broiler chicks were obtained from a local hatchery at 1
d of age. They were housed in electrically heated battery
Received for publication November 1, 1999.
Accepted for publication February 23, 2000.
1
Present address: Department Animal and Veterinary Sciences, College of Agriculture, Sultan Qaboos University, PO Box 34, Al-Khod 123,
Muscat, Sultanate of Oman.
2
To whom correspondence should be addressed: [email protected]
uoguelph.ca.
Abbreviation Key: AV = animal-vegetable fat; CCK = cholecystokinin.
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LIPASE ENZYME AND GUT FUNCTION
TABLE 1. Percentage diet composition and
calculated nutrient content
Ingredient
Corn
Soybean meal (48%)
Canola meal
Limestone
Calcium phosphate
Animal-vegetable fat
Iodized salt
DL-methionine
Vitamin-mineral premix1
Calculated nutrient content
ME, kcal/kg
Crude protein, %
Crude fat, %
Calcium, %
Available phosphorus, %
Methionine, %
Lysine, %
1 to 21 d
Starter
21 to 42 d
Grower
54.68
31.71
5.46
1.28
1.62
4.00
0.31
0.19
0.75
60.70
30.68
...
1.50
1.50
4.50
0.31
0.06
0.75
3,052
22.08
6.33
0.93
0.45
0.56
1.24
3,144
19.96
6.95
0.95
0.49
0.40
1.10
1
Provided per kilogram of diet: vitamin A, 8,000 IU (retinyl palmitate);
cholecalciferol, 40 mg; vitamin E, 11 IU (d1-α-tocopheryl acetate); riboflavin, 9.0 mg; biotin, 0.25 mg; pantothenic acid, 11.0 mg; vitamin B12,
13 µg; niacin, 26 mg; choline, 900 mg; vitamin K, 1.5 mg; folic acid, 1.5
mg; ethoxyquin, 125 mg; manganese, 55 mg; zinc, 50 mg; copper, 5 mg;
iron, 30 mg; and selenium, 0.1 mg.
brooders, and 24 h of light was provided. Feed and water
were provided ad libitum. Birds were fed a corn-soybean
meal diet containing 4% animal-vegetable (AV) blended
fat (Table 1).
Six treatments consisted of graded levels of Pancreatic威 enzyme3 (25 units USP/mg), namely 0, 0.214, 0.429,
0.643, 0.857, and 1.071% of the diet. There were six replicates for each of the six treatments, and each replicate
cage contained eight male broiler chicks. The unsupplemented diet was used to feed all chicks up to 3 d of age
to allow enough time to reduce any variation due to
nutrient absorption from yolk residue. From each replicate cage, six of the eight chicks, within the same range
of body weight, were introduced to experimental diets
on Day 4. A total feed intake per excreta collection procedure (Namkung and Leeson, 1999) was undertaken from
9 to 12 d, although these data are not reported in this
paper. On Day 12, one bird per replicate was killed by
cervical dislocation to examine the small intestine. A
section of jejunum 2 cm from Meckel’s diverticulum was
fixed in 10% buffered formalin, embedded in paraffin,
sectioned at 6 µ, and stained with hematoxylin and eosin
for observation using light microscopy.
Experiment 2
One hundred ninety-two commercial strain male
broiler chicks were obtained from a local hatchery at 1
d of age. They were housed in electrically heated battery
brooders, and 24 h of light was provided. Feed and
3
Enzyme Development Company, New York, NY 10121-0034.
Phillips Diagnostics, Mississauga, Ontario, Canada N0B 2K0.
4
957
water were provided ad libitum. Six dietary treatments
consisted of graded levels of Pancreatic威 enzyme,
namely 0, 0.268, 0.536, 0.804, 1.071, and 1.339% added
to the basal diet shown in Table 1. In this experiment,
the activity of Pancreatic威 enzyme was 20 units USP/
mg, and the concentration of this enzyme was adjusted
to equate the same enzyme activity (25 units USP/mg),
as used in Experiment 1. Feed intake was not recorded.
There were four replicates for each of six dietary treatments, and each replicate cage contained eight male
broiler chicks. At 12 d of age, six birds from each of the
control group and the highest level of enzyme were
subjected to a cineradiographic technique (Dzuik and
Duke, 1972). The examination began after administration
of 20 cc undiluted barium sulfate was given by gavage,
and it involved lateral and ventrodorsal fluoroscopic
examinations of birds placed in a restraint box, using a
Phillips Diagnost 66 System,4 and was recorded on Super-VHS media for review. No sedative or anesthetic
agents were administered. We recorded patterns of duodenal motility, refluxes per minute counted by the flow
of barium sulfate passing from the muscular stomach to
the duodenum and upper part of the ileum, and duodenal diameter. Wing tags attached to each bird from each
treatment controlled internal measurements, and this
procedure controlled any variation in radiographic magnification. At the end of the cineradiographic examination, three birds from each group were weighed and
then killed by cervical dislocation. The heart, jejunum
and ileum, and duodenal loop with pancreas were excised, dried with blotting paper, and weighed separately
for each bird. Because no significant differences were
observed, birds from other treatments were not tested.
Data collected were subjected to ANOVA, and when
significant differences were observed, means were further subjected to Tukey’s test. Statistical analysis of all
data was carried out by ANOVA (SAS Institute, 1991).
Experiment 3
Three hundred, 1-d-old male broiler chicks of a commercial strain were weight-sorted, wing-banded, and
randomly allocated to one of four diet treatment groups.
Each pen was 2.44 × 1.83 m, and these were located
in one of two identical rooms providing environmental
control. The temperature was maintained at 32 C for 5
d and was subsequently reduced gradually with normal
brooding practices. Lighting was at 80 lx for 23 h/d.
Feed and water were provided for consumption ad libitum. Four starter diets were formulated to provide a
similar nutrient profile (Table 1) with the exception of
using four graded levels of Pancreatic威 enzyme, namely
0, 0.375, 0.750, or 1.125% of the diet. There were three
replicates for each treatment, and each replicate pen contained 25 male broiler chicks. Experimental diets were
started when the chicks were 1 d old and were replaced
by a standard grower diet containing no enzyme, on
Day 21 for all treatment groups (Table 1). Body weight
gain, feed intake, and feed efficiency were determined
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AL-MARZOOQI AND LEESON
TABLE 2. Effect of supplemental Pancreatic威 enzyme on gastric motility and organ weights
(% body weight) of 12-d-old broiler chicks, Experiment 2
Dietary
treatment
Duodenal
refluxes per
minute
Duodenal
diameter
Heart
Jejunum and
ileum
Pancreas and
duodenum
0.87
0.86
NS
0.051
4.92
4.19
NS
0.352
2.37
2.19
NS
0.210
(mm)
Enzyme (%)
None
Pancreatic威 (1.071%)
Significance
Error mean square
5.87
5.10
NS
1.13
1.61
2.27
*
0.25
*P < 0.05.
for each replicate at 21 and 42 d. On Day 21, four birds
per replicate per treatment were weighed then killed by
cervical dislocation. The heart, liver, jejunum and ileum,
and duodenal loop with pancreas were excised, surface
dried using blotting paper, and weighed separately for
each bird. The liver only was removed at Day 42. The
data collected were subjected to regression analysis using the PROC REG function of SAS (SAS Institute, 1991).
zyme supplementation. There was no significant difference in feed intake and body weight gain among treatment groups from 21 to 42 d (when no enzyme was fed)
or when data were expressed over the 1 to 42 d grow-out
period. However, birds did utilize feed more efficiently
from 21 to 42 d when they had received prior (1 to 21
d) enzyme treatment at 1.125% (P < 0.05; Table 3) as
RESULTS AND DISCUSSION
Experiment 1
There was a significant (P < 0.01) linear decline in feed
intake from 4 to 12 d of age as lipase concentration
increased [(Y = 243.6 (± 4.0) − 127.3 (± 6.2)x), where Y =
grams feed intake per bird, and x = percentage inclusion
lipase enzyme]. Histological examination of the small
intestine from birds fed the highest dietary enzyme vs.
the control birds essentially showed no difference in
morphology, and there was no sign of villi effusion or
cell death (Figure 1).
Experiment 2
The cineradiographic study results showed no significant differences in gastric refluxes per minute between the two groups (Table 2). The duodenal diameter
of birds fed the diet supplemented with lipase enzyme
was significantly larger compared to that of the control
birds (P < 0.05; Table 3), even though these birds were
expected to eat less feed (Experiment 3). There was no
significant difference (P > 0.05) between the treatments
in percentage weight of the heart, small intestine, or
duodenal loop with pancreas (P > 0.05). These results
minimize the likelihood that the Pancreatic威 enzyme
used was contaminated with a polypeptide hormone,
which has been shown to depress gastroduodenal motility (Duke et al., 1979; 1985).
Experiment 3
Body weight gain, feed intake, and feed efficiency of
male broiler chicks are presented in Table 3 for 1 to 21,
21 to 42, and 1 to 42 d. From 1 to 21 d, there was a linear
decrease in growth and feed intake associated with en-
FIGURE 1. Section of jejunum (×100) from 12-d-old broiler chicks
fed the control diet (I) or the diet supplement with 1.071% dietary
Pancreatic威 enzyme (II). a) Intestinal wall, b) crypts, c) goblet cells, and
d) villi.
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LIPASE ENZYME AND GUT FUNCTION
TABLE 3. Effect of supplemental Pancreatic威 enzyme fed from 1 to 21 d on performance of male broilers, Experiment 3
1 to 21 d
Body
weight
gain/chick
Dietary
treatment
21 to 42 d
Feed
intake/chick
Feed:gain
Body weight
gain/bird
(g)
Enzyme (%)
None
0.375
0.750
1.125
Linear regression
Error mean square
600
588
561
473
**
39.5
Feed
intake/bird
1 to 42 d
Feed:gain
Body weight
gain/bird
(g)
994
978
943
847
**
32.5
1.65
1.67
1.68
1.78
NS
0.08
1,609
1,582
1,575
1,552
NS
104
Feed
intake/bird
Feed:gain
4,055
3,892
3,823
3,626
NS
216
1.84
1.81
1.79
1.79
NS
0.04
(g)
3,061
2,914
2,880
2,779
NS
188
1.90
1.84
1.83
1.79
**
0.39
2,209
2,170
2,136
2,025
NS
145
*P < 0.05.
**P < 0.01.
compared to the control group. Organ weights expressed
as a percentage of body weight at 21 and 42 d of age
are shown in Table 4. The percentage weight of the liver,
which was not different at 42 d, was significantly greater
at 21 d with the 1.125% enzyme compared to most other
treatments (P < 0.01; Table 4). All livers had a normal
shape and color similar to those of the control birds. The
increase in liver weight is perhaps due to the increase
in metabolic activity related to increased fat utilization.
The lipase enzyme seems to have no long-term effect
on feed intake or growth because 21 to 42-d performance
was unaffected. As stated previously, the clear pattern
of reduced feed intake and growth rate might be due to
the contamination of the lipase enzyme with products
such as CCK, which influences satiety signals and so
influences appetite (Antin et al., 1975; Savory and Gentle, 1980).
Various methods have been suggested as a means of
controlling growth and body weight gain in broilers and
breeder flocks at various times. Based on the results
obtained in Experiments 1 and 2, the histological examination of the small intestine and the cineradiographic
study showed that the reduced feed intake was not associated with changes in gut structure or with reduced
gastric motility. In addition, the grow-out study (Experiment 3) clearly showed that feeding the enzyme from 1
to 21 d of age does not have any long-term negative
carry-over effects. Therefore, this enzyme could be used
to control the body weight gain and growth rate in
broiler breeder pullets, because it can linearly reduce
feed intake and body weight gain without apparently
having any adverse effect on the physiology of the bird.
Although early growth depression, as a means of obtaining low-weight broiler breeder hens, can be achieved
by severe feed restriction or by feeding diets deficient
in selected nutrients, few systems are as effective as the
dose-related response shown in Table 3.
Therefore, it may be useful to study the role of Pancreatic威 enzyme in inducing controlled levels of anorexia
in both broilers and broiler breeders, because the Pancreatic威 enzyme seems to have some potential benefit in
inducing a voluntary reduction in feed intake. In terms
of improving fat utilization by young birds, it may be
beneficial to identify microbial sources of lipase, which
presumably would not be contaminated by any hormones active in the bird.
REFERENCES
Al-Marzooqi, W. S., 1998. Use of supplemental lipase enzyme
and detergent to improve fat digestion in poultry. M.Sc.
Thesis. University of Guelph, Guelph, Ontario, Canada.
Antin, J., J. Gibbs, J. Holt, R. C. Young, and G. P. Smith, 1975.
Cholecystokinin elicits the complete behavioral sequence
of satiety in rats. J. Comp. Physiol. Psychol. 89:784–790.
Duke, G. E., J. R. Kimmel, H. P. Hunt, and H. G. Pollock, 1985.
The influence of avian pancreatic polypeptide on gastric
secretion and motility in laying hens. Poultry Sci.
64:1231–1235.
TABLE 4. Effect of supplemental Pancreatic威 enzyme fed from 1 to 21 d on organ weights of male
broilers (% body weight), Experiment 3
21 d
Dietary treatment
Heart
Jejunum and
ileum
Enzyme (%)
None
0.375
0.750
1.125
Linear regression
Error mean square
0.68
0.67
0.69
0.68
NS
0.09
3.24
3.33
3.15
3.47
NS
0.35
**Significant at P < 0.01.
42 d
Pancreas and
duodenum
Liver
Liver
1.47
1.82
1.79
1.92
NS
0.24
2.87
3.06
3.02
3.34
**
0.26
1.51
2.58
2.28
2.54
NS
0.34
960
AL-MARZOOQI AND LEESON
Duke, G. E., J. R. Kimmel, P. T. Redig, and H. G. Pollock, 1979.
Influence of exogenous avian pancreatic polypeptide on
gastrointestinal motility of domestic turkeys. Poultry Sci.
58:239–246.
Dzuik, H. E., and G. E. Duke, 1972. Cineradiographic studies
of gastric motility in turkeys. Am. J. Physiol. 222:159–166.
Krogdahl, A., and J. L. Sell, 1989. Influence of age on lipase,
amylase, and protease activities in pancreatic tissue and
intestinal contents of young turkeys. Poultry Sci. 68:1561–
1568.
Namkung, H., and S. Leeson. 1999. Effect of phytase enzyme
on dietary AMEn and ileal digestibility of nitrogen and
amino acids in broiler chicks. Poultry Sci. 78:1317–1320.
Noy, Y., and D. Sklan, 1995. Digestion and absorption in the
young chick. Poultry Sci. 74:366–373.
SAS Institute, 1991. SAS User’s Guide. SAS Institute Inc.,
Cary, NC.
Savory, C. J., and M. J. Gentle, 1980. Intravenous injection of
cholecystokinin and caerulin suppress food intake in fowls.
Experientia (Basel) 36:1191–1197.

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