Integrated omics analysis reveals the differentiation of intestinal microbiota and metabolites between Pekin ducks and Shaoxing ducks

Pekin ducks and Shaoxing ducks are 2 Chinese local duck breeds, both domesticated from mallard, but after domestication and long-term artificial selection, the body weight of Pekin ducks is significantly higher than that of Shaoxing ducks. It is no debate that genetic factors are the main factors responsible for this difference, but whether intestinal micro- biota contribute to this difference is yet unknown. Thus, we performed comparative intestinal metagenomics and metabolomics analysis between Pekin ducks and Shaoxing ducks. We found obvious differentiation of intestinal metagenome and metabolome between the 2 breeds. Four cecal microbial genera, including Fusobacterium, Methanobrevibacter, Butyricicoccus, and Anaerotignum showed higher abundance in Pekin ducks. Among them, Methanobrevibacter and Butyricicoccus may positively correlate with fat deposition and body weight. A total of 310 metabolites showed difference between the 2 breeds. Functions of these differential metabolites were mainly enriched in amino acid metabolism, including energy metabolism-related histidine metabolism. Integrated omics analysis showed that microbial changes were closely related to altered metabolites. Especially, Butyricicoccus showing higher abundance in Pekin ducks was significantly negatively correlated with D-glucosamine-6-phosphate, , which has been reported to prevent body weight gains. These findings may contribute to further understand the difference in body weight between Pekin ducks and Shaoxing ducks.