Modulation of Immune Response and Cecal Microbiota by Dietary Fenugreek Seeds in Broilers

Simple Summary Fenugreek seeds, a natural source of bioactive compounds, were tested for their effects on the immune system and gut bacteria of broiler chickens. Broilers were fed three diets: control, low fenugreek seed powder (5 g/kg), and high fenugreek seed powder (10 g/kg). The results showed that fenugreek seeds downregulated genes related to inflammation and antimicrobial defense, suggesting reduced inflammation, and improved immune response. Fenugreek increased the "good" Firmicutes bacteria and decreased the "bad" Actinobacteriota, Gemmatimonadota, and Verrucomicrobiota. It also boosted beneficial Alistipes, Bacteriodes, and Prevotellaceae bacteria. In conclusion, fenugreek seeds positively impact broiler chickens' immune systems and gut bacteria, possibly by influencing how these two systems interact. This suggests the potential for fenugreek as a natural health promoter in poultry production.Abstract Fenugreek seeds (FSs) are a natural source of bioactive compounds that may modulate the immune system and gut microbiota in broilers. This study examined the effects of dietary fenugreek seed powder on immune-related gene expression and cecal microbiota composition in broilers. A total of 144 broiler chickens were randomly allocated to three dietary groups, CON (0 g/kg FS, FS5 (5 g/kg FS) and FS10 (10 g/kg FS), each with 6 replicates of 8 birds. Ileum tissues and cecal contents were collected on day 42 for the mRNA expression of inflammation and antimicrobial defense-related genes and cecal microbiome diversity, respectively. The results indicated that fenugreek seeds downregulated mRNA-level inflammation and antimicrobial defense-related genes: IL6, IL8L2, CASP6, PTGS2, IRF7, AvBD9, AvBD10, and AvBD11. Moreover, fenugreek seeds altered the cecal microbial community by increasing the population of Firmicutes and decreasing the population of Actinobacteriota, Gemmatimonadota and Verrucomicrobiota at the phylum level and increasing Alistipes, Bacteriodes and Prevotellaceae at the genera level. These findings suggest that fenugreek seeds have a positive impact on the immunological profile and microbiome of broiler chickens, possibly through the interplay of the immune system and the gut microbiome.