Efficacy of Synbiotics to promote gut integrity and reduce Salmonella colonization in broilers

The aim of this experiment was to study the efficacy of Synbiotics (a combination of Saccharomyces cerevisiae, Bacillus subtilis, B. licheniformis, Lactobacillus acidiophilus, L. plantarum, L. lactis, Streptococcus thermophillus and Fructooligosaccharides) to promote gut integrity and reduce Salmonella colonization. Two hundred and forty, one-day-old, female chicks were divided into 4 groups of 60 each. Each group was divided into 3 replicates of 20 each. Birds in-group 1-3 were served as treatment groups. Birds in group 4 was a positive control group. Birds in-group 1 were provided Synbiotics 2 ml/L drinking water (DW) skip a day from 1-42 days of age (6 hr/day). Birds in-group 2 were provided synbiotics 2 ml/L DW for 3 consecutive days (6 hr/day) in each week. Birds in-group 3 were provided Synbiotics 1 ml/L DW every day from 1-42 days of age (6 hr/day). Birds in-group 4 were provided fresh water ad lib. At 21 and 42 day-old, three birds in each replicates were euthanized to collect intestine for histopathology analysis, and also collect rectal content to test for butyric acid activity. Body weight and feed conversion ratio was calculated at 21 and 42 day-old. At 21 day-old, all birds were challenged with 1ml of Salmonella Enteritidis Nalidixic acid resistance strain (108 cfu/ml). At 21 and 28 day-old, birds were cloacal swabbed for testing for Salmonella colonization.

The results revealed that at 21 and 42-day-old birds in treatment groups showed better villi height and crypt depth than those birds in positive control group especially in the duodenum. At 21-day-old, birds in group 1 revealed significantly higher duodenum villi height and crypt depth (910.75±416.39; 77.78±48.70) than those of birds in group 4 (709.05±93.86; 39.52±9.74) (P<0.05). In addition, at 21-day-old, butyric acid activity of birds in treatment groups 1 (4.28±2.50), 2 (3.04±2.70) and 3 (4.07±2.20), showed significantly higher than birds in group 4 (1.91±1.51) (P<0.05). At 42-day-old, average body weight (kg) and FCR of birds in-group 1 (2.08±0.34; 2.27±0.09), 2 (2.17±0.15; 2.14±0.03), 3 (2.04±0.36; 2.23±0.06) showed better than birds in-group 4 (1.99±0.42; 2.37±0.18). At 21 day-old (before challenge), no S. Enteritis Nalidixic acid resistant strain was found in any group. However, at 28 day-old, S. Enteritis Nalidixic acid resistant strains were found lower in treatment group 1 (78%), 2 (78%), 3 (68%) than the positive control group 4 (100%). In conclusion, Synbiotics promoted the chicken performance and gut morphology and butyric acid activities.

Keywords: butyric acid activity, gut integrity, synbiotics, Salmonella reduction.

Abstract presented at the 3rd International Symposium on Alternatives to Antibiotics 2019.