RESUMO
The present study investigated the effects of live yeast cultures (LYC) on growth performance, gut health indicators, and immune responses in broiler chickens. A total of 720 mixed-sex broilers (40 birds/pen; 9 replicates/treatment) were randomly allocated to two dietary treatments: (1) a basal diet based on corn-soybean meal (CON) and (2) CON with 1 g/kg LYC. At 35 d of age, one bird per replicate pen was chosen for biopsy. LYC group tended (P < 0.10) to increase average daily gain during the grower phase compared with CON group. Broilers fed LYC diet had increased (P = 0.046) duodenal villus height and area but reduced (P = 0.003) duodenal crypt depth compared with those fed CON diet. Birds fed LYC diet presented alleviated (P < 0.05) serum TNF-α, IL-1ß, and IL-6 levels compared with those fed CON diet. Further, birds fed LYC diet exhibited upregulated (P < 0.05) ileal tight junction-related proteins and pro-inflammatory cytokines in the ileal tissue compared with those fed CON diet. Inverse Simpson's diversity (P = 0.038) revealed that birds fed CON diet had a more diverse microbiota community in the ileal digesta, compared with those fed LYC diet, while no significant difference between the treatments on Chao1 and Shannon's indices was observed. Based on the weighted UniFrac distance, the PCoA showed that microbiota in the ileal digesta of the LYC group was different from that of the CON group. LYC group increased the abundance of the phyla Firmicutes and genera Lactobacillus, Prevotella, and Enterococcus compared with CON group. The present study demonstrated that supplemental LYC as a feed additive provide supportive effects on enhancing gut functionality by improving the upper intestinal morphology and gut integrity, and modulating the immune system and microbiota communities of birds.
Live yeast culture (LYC) is composed of Saccharomyces cerevisiae and its metabolites such as mannan-oligosaccharides, peptides, nucleotides, vitamins and unknown growth factors. The supplementation of LYC is expected to exert health benefits in animals; however, the responses of broiler chickens to supplemental LYC is not fully explored. Thus, the present study evaluated the effects of LYC supplementation on growth performance, immune responses and intestinal health in broiler chickens. Based on the results from the present study, supplementation of LYC to a corn-based diet did not affect growth performance. Nonetheless, supplemental LYC improved intestinal morphology, upregulated tight junction-related protein genes and altered ileal microbiota diversity, suggesting its health benefits in improving gut health. In addition, supplemental LYC modulated serum immune responses and ileal cytokine genes expression, presenting its immunomodulatory potential.
