Supplementation with Akkermansia muciniphila improved glucose metabolism disorder in common carp (Cyprinus carpio L.)

Akkermansia muciniphila (Akk), a promising next-generation probiotics, has been identified as an effective means for alleviating hepatic steatosis and insulin resistance in mammals. However, its probiotic effect and mechanism remain unclear so far in aquaculture. This study aimed to investigate how Akk is involved in the glucose metabolism of common carp and its mechanism. A total of 300 healthy carp with the same size (26.5 ± 3.0 g) were randomly divided into four groups: G25/A0 group (25% glucose +0 CFU/g Akk), G25/A108 group (25% glucose +1 × 108 CFU/g Akk), G50/A0 group (50% glucose +0 CFU/g Akk), and G50/A108 group (50% glucose +1 × 108 CFU/g Akk). These groups were placed into three replicate tanks (25 fish/tank). At the end of a 60-day feeding trial, the effects of Akk supplementation on the growth performance, glucose metabolism, and intestinal microflora composition of common carp were investigated. Then, a short-term gavage experiment was conducted to further explore the regulatory effects of live Akk, pasteurized Akk, and cell-free supernatant on the glucose metabolism of carp. The results showed that Akk reduced the blood glucose and TG content of carp fed with high glucose, promoted glycolysis, inhibited liver gluconeogenesis, and reduced the diversity and richness of intestinal microbiota. The pasteurized Akk displayed a stronger role in reducing serum TG and promoting glycolysis than the live Akk and cell-free supernatant. In summary, Akk may be considered as one of the ideal new probiotics used in aquaculture.