Abstract
This research aimed to investigate the effects of supplements containing fermented feed made from Citri Sarcodactylis Fructus by-products (CSFBP-Fermented feed) on the growth performance, immunological function, and gut health of broilers. 1080 cyan-shank partridge birds aged 47 days were chosen and casually distributed to four groups, each with 6 replicates and 45 birds per replicate. The experimental groups were provided with 1% (group T2), 3% (group T3) and 5% (group T4) of CSFBP-fermented feed in the basic diet, while the control group (group T1) received the basic diet. The findings revealed that supplementation with CSFBP-Fermented feed reduced ADFI and FCR and improved ADG in birds (P < 0.05). MDA levels in the serum of birds fed CSFBP-fermented feed were lower than in the control group (P < 0.05). The CAT activity in the serum of broilers increased after supplementation with 3% CSFBP-Fermented feed (P < 0.05). Supplementing broilers with CSFBP-fermented feed enhanced VH in the ileum, jejunum, and duodenum (P < 0.05). The addition of 3% CSFBP-Fermented feed decreased CD in the jejunum (P < 0.05). The addition of 3% and 5% CSFBP-Fermented feed increased the mRNA expression of ZO-1 and Occludin in the jejunum of broiler chickens and reduced the mRNA expression of IL-6 (P < 0.05). The addition of 3% CSFBP-Fermented feed increased the mRNA expression of Claudin in the jejunum of broiler chickens and reduced IL-1β mRNA expression (P < 0.05). Compared to the control group, all experimental groups exhibited decreased mRNA expression of TNF-α and INF-γ in the jejunal mucosa of the birds (P < 0.05). According to research using high-throughput sequencing of microorganisms' 16S rDNA, and an analysis of α-diversity found that supplementing broilers with 3% CSFBP-Fermented feed decreased the number of bacteria in their cecum (P < 0.05). Bacteroidota was higher in all groups after supplementation with CSFBP-Fermented feed. At the genus level, after addition with 3% CSFBP-Fermented feed, the abundance of Bacteroide and Prevotellaceae_Ga6A1_group were higher than the control group (33.36% vs 29.95%, 4.35% vs 2.94%). The abundance of Rikenellaceae_RC9_gut_group and Fusobacterium were lower than the control group (5.52% vs. 7.17%,0.38% vs. 1.33%). In summary, supplementing the diet with CSFBP-Fermented feed can promote the growth of performance by enhancing intestinal morphology, and barrier function, as well as modulating intestinal inflammatory factors and microbial composition in broilers.