Fig. 3

Methionine supplementation-induced gut microbiota changes of laying hen digesta. To confirm the practical application of methionine, the small intestine digest of healthy broilers was co-cultured with methionine using FIMM (in vitro microbial culture) and the gut microbiota was analyzed. (A) The digesta pH changes were measured during incubation. (B) The richness of the digesta microbiota was assessed through alpha-diversity metrics, specifically employing Chao and Shannon indices. The results are presented as the mean ± SD. (C) To compare the diversity of the digesta microbiota across different groups, PCoA plots were utilized, grounded in both weighted and unweighted UniFrac distances pertaining to the microbiome of laying hens digesta. Each plot symbolizes an individual replicate, with the axes depicting the two principal dimensions that capture the most significant variance within the microbial communities. (D) Compositional changes were analyzed under phylum, family, genus, and species level and (E) pathogenic population of Campylobacter. The values are expressed as mean ± SD; significant differences were determined using one-way ANOVA followed by Student’s t-test at *P < 0.05 compared with Cont