Dietary supplementation of distiller's grains yeast cultures improves performance and immunity by altering the intestinal flora of broilers.

Background: Distiller's grains are a by-product of liquor production with a higher yield than liquor. Developing and utilizing distiller's grains well could alleviate the problem of scarce feed resources. Our present experiment was conducted with 6000 yellow-feathered broilers to study the effects of adding distiller's grains yeast cultures (DGYC) to the diet on growth performance and immunity of broilers. The broilers were divided into five groups, receiving different DGYC concentrations during two stages. Growth performance, intestinal microorganisms and immune organ development were measured.

Results: The results showed that groups B and D, supplemented with medium and high concentrations of DGYC, respectively, had significantly improved growth performance compared to the control group (P < 0.05). Group D also showed higher immune organ index (P < 0.01), increased serum total protein, high-density lipoprotein and immunoglobulin levels (P < 0.05) and lower levels of low-density lipoprotein, triglycerides, interleukin 1β and tumor necrosis factor α (P < 0.05). Hematoxylin and eosin staining confirmed improved immune organ development in group D (P < 0.05). Furthermore, in high-concentration group D, levels of short-chain fatty acids (SCFA; acetic, propionic and butyric acids) in cecal chyme were significantly increased (P < 0.05). The richness (Chao1) and diversity (Faith-pd) index of cecal microbiota were significantly higher in group D compared to the control group (P < 0.05). The microbial composition in group D differed from the control and medium-concentration group B. Seven bacteria (Clostridia-UCG-014, UCG-009, DTU089, UCG-010, Campylobacter, Harryflintia, Shuttleworthia) showed significant differences (P < 0.05). After DGYC feeding, DTU089 decreased, while other SCFA-producing bacteria increased (P < 0.05). Subsequently, KEGG function and corresponding signal pathway predictions were performed on bacteria with significant differences. Group D exhibited a higher enrichment of immune function pathways (P < 0.01) and showed significant changes in four immune signaling pathways according to the signal pathway heatmap.

Conclusion: Our data suggest that high concentrations of DGYC can be applied as a feed additive for broilers that promotes growth, improves intestinal health and enhances certain immunity. © 2024 Society of Chemical Industry.