Probiotic cocktails accelerate baicalin metabolism in the ileum to modulate intestinal health in broiler chickens.

BACKGROUND: Baicalin and probiotic cocktails are promising feed additives with broad application prospects. While probiotic cocktails are known to enhance intestinal health, the potential synergistic impact of combining baicalin with probiotic cocktails on the gut health of broiler chickens remains largely unexplored. Therefore, this study aims to investigate the influence of the combined administration of baicalin and probiotic cocktails on the composition of ileal and cecal microbiota in broiler chickens to elucidate the underlying mechanisms responsible for the health-promoting effects. RESULTS: A total of 320 1-day-old male Arbor Acres broilers were divided into 4 groups, each with 8 replicates of 10 chicks per replicate. Over a period of 42 d, the birds were fed a basal diet or the same diet supplemented with 37.5 g/t baicalin (BC), 1,000 g/t probiotic cocktails (PC), or a combination of both BC (37.5 g/t) and PC (1,000 g/t). The results demonstrated that BC + PC exhibited positive synergistic effects, enhancing intestinal morphology, immune function, and barrier function. This was evidenced by increased VH/CD ratio, sIgA levels, and upregulated expression of occludin and claudin-1 (P < 0.05). 16S rRNA analysis indicated that PC potentiated the effects of BC, particularly in the ileum, where BC + PC significantly increased the α-diversity of the ileal microbiota, altered its ß-diversity, and increased the relative abundance of Flavonifractor (P < 0.05), a flavonoid-metabolizing bacterium. Furthermore, Flavonifractor positively correlated with chicken ileum crypt depth (P < 0.05). While BC + PC had a limited effect on cecal microbiota structure, the PC group had a very similar microbial composition to BC + PC, suggesting that the effect of PC at the distal end of the gut overshadowed those of BC. CONCLUSIONS: We demonstrated the synergistic enhancement of gut health regulation in broiler chickens by combining baicalin and probiotic cocktails. Probiotic cocktails enhanced the effects of baicalin and accelerated its metabolism in the ileum, thereby influencing the ileal microbiota structure. This study elucidates the interaction mechanism between probiotic cocktails and plant extract additives within the host microbiota. These findings provide compelling evidence for the future development of feed additive combinations.

Methionine Source and Level Modulate Gut pH, Amino Acid Transporters and Metabolism Related Genes in Broiler Chickens.

This study determined the effects of two methionine (Met) sources at three total sulfur amino acids (TSAA) to lysine ratios (TSAA/Lys) on gut pH, digestive enzyme activity, amino acid transporter expression, and Met metabolism of broilers. The birds were randomly assigned to a 2 × 3 factorial arrangement with Met sources (dl-Met and dl-2-hydroxy-4-(methylthio)-butanoic acid (OH-Met)) and TSAA/Lys (0.58, 0.73, and 0.88) from 1 to 21 days. The results demonstrated that dl-Met and OH-Met supported the same growth performance, but high TSAA/Lys ratio reduced the feed intake and body weight (P < 0.05). OH-Met reduced the crop chyme pH and enhanced the jejunal lipase activity (P < 0.05). ATB0,+ expression decreased with increased dl-Met levels in the duodenum; the low TSAA/Lys ratio induced a stronger mRNA expression of basolateral Met transporters. OH-Met resulted in an increase of cystathionine ß-synthase expression in the liver and a decrease in serum homocysteine levels at middle TSAA/Lys ratio compared with dl-Met treatment (P < 0.05). In conclusion, two Met sources support the same growth, but OH-Met acidified the crop chyme. The investigated transporter transcripts differed significantly along the small intestine. At the middle TSAA/Lys ratio, OH-Met showed a higher metabolic tendency of the trans-sulfuration pathway compared with dl-Met.

Mannanase improves the growth performance of broilers by alleviating inflammation of the intestinal epithelium and improving intestinal microbiota.

This experiment aimed to discuss and reveal the effect and mechanism of mannanase on intestinal inflammation in broilers triggered by a soybean meal diet. In this experiment, 384 Arbor Acres broilers at 1 d old were randomly divided into 3 treatment groups. The broilers were fed a corn-soybean meal basal diet, a low-energy diet (metabolizable energy reduced by 50 kcal/kg), and a low-energy diet supplemented with 100 mg/kg mannanase for 42 d. The low-energy diet increased feed conversion ratio from 0 to 42 d, reduced ileal villus height and villus height-to-crypt depth ratio and upregulated the expression of nuclear factor kappa B (NF-κB) in the ileum (P < 0.05). It also reduced cecal short-chain fatty acids (SCFA), such as acetic acid (P < 0.05). Compared with low-energy diets, the addition of mannanase increased body weight at 42 d, promoted the digestibility of nutrients, and maintained the morphology and integrity of the intestinal epithelium of broilers (P < 0.05). In addition, mannanase upregulated the expression of claudin-1 (CLDN1) and zonula occludens-1 (ZO-1) in the jejunum at 21 d, downregulated the expression of ileal NF-κB, and increased the content of isobutyric acid in the cecum of broilers (P < 0.05). The results for the ileal microbiota showed that a low-energy diet led to a decrease in the relative abundance of Lactobacillus reuteri in the ileum of broilers. The addition of mannanase increased the relative abundance of Lactobacillus-KC45b and Lactobacillus johnsonii in broilers. Furthermore, a low-energy diet reduced the relative abundance of Butyricicoccus in the intestine of broilers and inhibited oxidative phosphorylation and phosphoinositol metabolism. Mannanase increased the relative abundance of Odoribacter, promoted energy metabolism and N-glycan biosynthesis, and increased the activities of GH3 and GH18. It is concluded that mannanase could improve the growth performance of broilers by reducing the expression of NF-κB in the ileum, increasing the production of SCFA in the cecum, suppressing intestinal inflammation, balancing the intestinal microbiota, reducing damage to the intestinal barrier, and improving the efficiency of nutrient utilization to alleviate the adverse effects caused by the decrease in dietary energy level.