Comparative Analysis of Fecal Microbiota and Metabolomic Profiles in Male and Female Leizhou Goats Offered a 10% Crude Protein Diet Among Four Energy Levels.

The gut microbiota plays a crucial role in maintaining the host's metabolism and can influence the host's productivity. Both dietary composition and gender have distinct effects on the composition of the gut microbiota. Therefore, to investigate the differences in the structure and function of the gut microbiota between female and male goats, we analyzed their fecal microbiota and metabolites when fed a 10% crude protein diet at four different energy levels-7.01, 8.33, 9.66, and 10.98 MJ/kg DM. Four non-pregnant female and four male Leizhou goats (all 8 months of age) were used in the experiment, with an average body weight of 10.3 ± 0.8 kg for females and 13.6 ± 1.1 kg for males (mean ± SD). The animals were assigned to two separate 4 × 4 Latin square designs according to their gender, each consisting of four treatments and four 28-day periods, including 25 days of a dietary adaptation period and 3 days of fecal sample collection per period. The data were analyzed using the SAS statistical package and Pearson's correlation analysis. The dominant phyla for all samples were Firmicutes and Bacteroidota, regardless of dietary energy levels or gender. Among fecal bacteria,