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Véronique Demers-Mathieu 1,2,3, Mélanie Le Barz 2,3, Noémie Daniel 2,3, Geneviève Pilon 2,3, André Marette 2,3, Julie Audy 4, Emilie Laurin 5, Ismaïl Fliss 2, Daniel St-Gelais 1,2 1 Agriculture and Agri-Food Canada, Food Research and Development Centre, Saint-Hyacinthe, QC, Canada, 2 Institute of Nutrition and Functional Foods (INAF), Laval University, QC, Canada, 3 Quebec Heart and Lung Institute (CRIUCPQ), QC, Canada, 4 Agropur Coopérative, St-Hubert. QC, Canada, 5 Aliments Ultima Inc. Longueuil, QC, Canada Results & Discussion Anti-obesity effect of probiotic strains in yogurt and milk (a) Probiotic milk (b) Probiotic milk Prise de poids Body weight gain 2.5 1.5 0.5 A) Identification of new probiotic strains 0 0.0 § Probiotic milk: Eight-week-old C57Bl/6J male mice (n=12, Charles River) were used. § Probiotic yogurt: Eight-week-old C57Bl/6J male mice (n=12, Jackson Laboratory) were used. Mice were fed with a high-fat high-sucrose (HFHS: induced obesity) diet (65% lipids, 15% proteins & 20% sucrose). The term ‘control’ refers to mice fed a normal chow diet (healthy control) or a HFHS diet without probiotic (WP) (induced obesity control). Animals were treated by daily gavage with probiotic milk or yogurt receiving daily doses of 1 x 109 cfu per portion After 7 weeks, food was withdrawn overnight and the mice then received glucose (1 g/kg body weight) by gavage for blood glucose measurement. After 8 weeks of feeding, animals were sacrificed and epididymal white adipose tissue (eWAT) were collected and weighed. § Mice fed with chow diet (healthy control) 30 40 50 Mice fed with HFHS diet during 8 weeks ² Body weight gain was reduced considerably when the milk contained probiotic Bf141 or Lb102 (Fig. 1a). ² Daily gavage with yogurt containing either probiotic adjunct Bf141 and Lb102 clearly had no effect on body weight gain (Fig.1d). ² Mice fed the HFHS diet gained on average more weight and became obese, whether the daily gavage was with milk or yogurt (Fig.1a,d) Effect of probiotic on epididymal adipose tissue (Visceral) mass: ² The increase in eWAT mass in mice fed the HFHS diet were lessened when the daily gavage was milk with Bf141 or Lb102 (Fig. 1b). ² Neither probiotic adjunct in yogurt had any significant effect on the HFHS-induced increase in total eWAT mass (Fig. 1e). ² eWAT mass were lower in mice fed the chow diet than in mice fed the HFHS diet, whether the treatment was with milk or yogurt (Fig. b,e). Effect of probiotic in milk and yogurt on glycaemia in mice ² The effect of the HFHS diet on blood glucose concentration was lessened in mice fed either probiotic milk with Bf141 or Lb102 (Fig. 1c) ² The probiotic yogurts had no significant effect, whether with Bf141 or Lb102 (Fig. 1f) ² Mice fed the chow diet had lower blood glucose than did the HFHS diet group, HFHS diet induced glucose intolerance (Fig. 1c, f) Viability of the probiotic in the mouse digestive system 12.0 10.0 8.0 12.0 (a) Milk c d 6.0 a b de e 4.0 2.0 Bf141 Treated with Treated with Treated with Treated with Treated with Treated with Treated with Treated with milk WP yogurt WP milk WP Bf141 milk Lb102 milk yogurt WP Bf141 yogurt Lb102 yogurt WP: Without probiotic E) Bacterial count in yogurt, milk and faeces On days 55 and 56, fresh faeces of three mice per HFHS group was collected before and 4 h after. The morphology of colonies on agar was compared to that of pure Bf141 and Lb102 plated on the same conditions (MRS agar with bile extracts (0.15 % w/ v) (37°C) + Anaerobic condition for 72 h). 1 20 Effect of probiotic in milk and yogurt on weight gained by mice: 0h • 10 Fig. 1: Body weight gain (a,d), epididymal white adipose tissue (eWAT) mass (b,e) and blood glucose concentration (c, f) of mice treated by daily gavage with (a) milk or (b) yogurt after 8 week. Chow: mice fed with chow diet treated with milk or yogurt WP; HFHS: mice fed with high fat/ high sucrose (HFHS) diet treated with milk or yogurt WP; Bf141 or Lb102 : mice fed with HFHS diet treated with Bifidobacterium animalis ssp. lactis Bf141 or Lactobacillus rhamnosus Lb102 in milk or yogurt. 0.0 • ow 0.0 * Ch Add probiotic (Bf141 or Lb102) freezing-drying in yogurt D) Determination of anti-obesity effect in vivo § 0 4h Lb102 Control Population log (cfu /g) 1 x 109 cfu of probiotic per 200 µL yogurt Stirred yogurt Cooling + Storage (4°C) § 0.5 0 Population log (cfu /g) Fermentation (42°C until pH 4.65) 1 x 109 cfu of probiotic per 110 µL milk § 2 Days Add probiotic (Bf141 or Lb102) freezing-drying in milk § 1.0 14 Thermophilic starter + probiotic strains (Bf141 or Lb102) + yogurt milk 4 1.5 Bf Skim milk 6 2 C) Probiotic yogurt 2.0 10 Lb102 Blood glucose eWAT Lb Bf141 (f) Probiotic yogurt eWAT Chow yog HFHS yog Lb102 yog Bf141 yog 8 Bf141 B) Probiotic milk 10 ow Total Body weight gain Body weight "Yogourt" Bodygain weight gain Weight(g) Lb102 50 (e) Probiotic yogurt Body weight (g) Lb. rhamnosus B. animalis ssp lactis 40 (d) Probiotic yogurt Strains: RAPD-PCR - primer OPA-16 for Bf - primer cra22 for Lb Strains 30 HF HS Subspecies: - qPCR primers for Bifidobacterium (Bf) - rplB gene for Lactobacillus (Lb) Species 20 Ch Species: Analysis of the 16S rDNA ( ≥ 98%) 10 1 2 14 1.0 Materials et Methods 0 * Bf 4 * 2 6 2.0 10 Chow HFHS Lb102 Bf141 8 Blood glucose eWAT HF HS 10 (c) Probiotic milk eWAT Lb Total Body weight gain Weight(g) Several studies have demonstrated that the gut microbiota as one of the most origin of metabolic disorders such as obesity and type 2 diabetes (1, 2). Western obesogenic diet (i.e. rich in saturated/trans fat and simple sugars and poor in fibers) can importantly alter gut microbiota (i.e. dysbiosis) leading to the production of pro-inflammatory cytokines and metabolic endotoxemia, therefore promoting obesity (3). To counteract these negative effects, probiotics (Lactobacillus, Bifidobacterium) have been used to shaping the gut microbiota and then prevent inflammation and obesity. No study has compared, until now, the anti-obesity effect of new probiotic strains contained in milk and yogurt. In this study, the anti-obesity effect of two new probiotic strains was compared in non-fat yogurt and skim milk using a model mice obese. The survival of probiotic strains after the digestion of probiotic yogurt and milk was also determined. Poids (g) Introduction 10.0 8.0 Conclusion (b) Yogurt a c d 6.0 ² The body weight gain, visceral fat mass and plasma glucose (glucose intolerance) in mice fed with HFHS was more reduced with Bifidobacterium animalis ssp. Bf141 and Lactobacillus rhamnosus Lb102 milk than with control WP milk. • Anti-obesity effect of probiotic milks was more effective than that of the probiotic yogurts. Probiotic components associated with anti-obesity effect such as cell constituents (polysaccharide, peptidoglycan, DNA, teichoic acids and secreted proteins, organic acids, bacteriocins, polyphosphates and fatty acids) could be reduced by thermophilic starter or yogurt ingredients. • Bf141 was more resistant than Lb102 to gastrointestinal transit, whether fed in milk or yogurt, but the post-transit counts of both probiotic isolates remained above 1 x 108 cfu g-1. • Additional studies are needed to further this research. b de e 4.0 2.0 0.0 0h Bf141 4h Lb102 Control Fig. 2: Viable counts of faecal Bifidobacterium animalis ssp. Bf141 and Lactobacillus rhamnosus Lb102 before (0h) and after (4h) gavage of mice using (a) milk or (b) yogurt after 8 weeks. ² • The Bf141 counts were similar whether the mice were fed milk or yogurt. The same was noted for Lb102. The bacterial count was higher in the case of Bf141 than Lb102, and higher for both isolates than the control gavage treatment, whether milk or yogurt. References & Acknowledgments (1) Arora et al. (2013) Nutr. 29:591; (2) Park et al. (2013) Plos one 8 :e59470; (3) Le Barz et al. (2015) Diabetes Metab 39:291. This project was funded by NSERC, Agropur and Aliments Ultima Inc.. Thank you M. Bélanger and Mme Bernard for technical help.