Comprehensive omics analysis of the fecal microbiome and serum metabolome in Dezhou donkey foals at the end of weaning and after weaning.

Weaning is essential for foal growth and development. We determined the intestinal flora structure of donkey foals at the end of weaning (PreW_4d) and three stages after weaning (PostW_4d, PostW_8d, and PostW_15d) to explore the effects of weaning on intestinal development of donkey foals. The results showed that the main microbial flora in the gut of the donkey foal were Firmicutes and Bacteroides, and the proportion of Firmicutes gradually increased with weaning, which was an important reflection of the donkey foal's adaptability to the transition from lactose liquid feed to plant fiber solid feed. We also identified important microorganisms that maintain intestinal stability and boost immune, such as oscillospiraceae, Firmicutes, and lachnospiraceae. The metabolome showed that serum metabolites were mainly enriched in arachidonic acid metabolism and the tricarboxylic acid cycle (TCA cycle), which can influence energy metabolism, growth, and immunity in weaned donkey foals. We also found that the metabolite resveratrol was positively correlated with g_NK4A214_group and lactobacillus, which may have important implications for the prevention of diseases such as colon-inflammation in donkey foals. In summary, we provide a theoretical basis for studying the mechanism of intestinal microbiome and serum metabolite changes in weaning and postweaning donkey foals.