Bacillus Coagulans Enhance the Immune Function of the Intestinal Mucosa of Yellow Broilers

ABSTRACT This experiment was conducted to investigate the effects of Bacillus coagulans on the growth performance and immune functions of the intestinal mucosa of yellow broilers. Three hundred and sixty one-day-old yellow chicks were randomly allocated to four treatments groups with six replicates of 15 chicks each. The broilers were randomly subjected to one of the following treatments for 28 days: control group (group1, fed a basal diet) and three treatments (group 2, 3, 4) fed the basal diet supplemented with 100, 200, or 300 mg/kg Bacillus coagulans , respectively). The results showed that for 28 days, compared with the control diet, the dietary addition of 200 mg/kg Bacillus coagulans significantly decreased the feed/gain ratio (F/G) (p<0.05), improved the thymus index, spleen index and bursa index (p<0.05), increased the villus height to crypt depth ratio (V/C) in the duodenum (p<0.05), increased the number of secretory immunoglobulin (sIgA) positive cells ( p<0.05). The dietary addition of 200 mg/kg Bacillus coagulans promoted a significant increase in Lactobacillus spp. populations and suppressed Escherichia coli replication in cecum, compared with the control (p<0.05). Moreover, the dietary addition of 200 mg/kg Bacillus coagulans also significantly enhanced the levels of interferon alpha (IFNα), toll-like receptor (TLR3), and melanoma differentiation-associated protein 5(MDA5) in the duodenum (p<0.05). In conclusion, the dietary addition of Bacillus coagulans significantly improved broiler performance, and enhanced the intestinal mucosal barrier and immune function. The optimal dosage of Bacillus coagulans for yellow broilers was determined as 2×108 cfu/kg.