Effect of riboflavin deficiency on intestinal morphology, jejunum mucosa proteomics, and cecal microbiota of Pekin ducks

This study was to determine the effects of riboflavin deficiency (RD) on intestinal development, jejunum mucosa proteome, cecal short-chain fatty acids (SCFA) profiling, and cecal microbial diversity and community of starter Pekin ducks. Male white Pekin ducks (1 d old, n = 240) were allocated into 2 groups, with 12 replicates and 10 birds per replicate in each group. For 21 d, all ducks had ad libitum access to either an RD or a riboflavin adequate (control, CON) diet, formulated by supplementing a basal diet with 0 or 10 mg riboflavin per kg of diet, respectively. Compared to the CON group, growth retardation, high mortality, and poor riboflavin status were observed in the RD group. Furthermore, RD reduced the villus height and the ratio of villus height to crypt depth of jejunum and ileum (P < 0.05), indicating morphological alterations of the small intestine. In addition, dietary RD enhanced relative cecum weight and decreased cecal SCFA concentrations (P < 0.05), including propionate, isobutyrate, butyrate, and isovalerate. The jejunum mucosa proteomics showed that 208 proteins were upregulated and 229 proteins were downregulated in the RD group compared to those in the CON group. Among these, RD mainly suppressed intestinal absorption and energy generation processes such as glycolysis and gluconeogenesis, fatty acid beta oxidation, tricarboxylic acid cycle, and oxidative phosphorylation, leading to impaired ATP generation. In addition, RD decreased the community richness and diversity of the bacterial community in the cecum of ducks. Specifically, RD reduced the abundance of butyrate-producing bacteria in the cecum (P < 0.05), such as Eubacterium coprostanoligenes, Prevotella and Faecalibacterium. Dietary RD resulted in growth depression and intestinal hypofunction of Pekin ducks, which could be associated with impaired intestinal absorption and energy generation processes in intestinal mucosa, as well as gut microbiota dysbiosis. These findings contribute to our understanding of the mechanisms of intestinal hypofunction due to RD.