Correlation of gut microorganisms and non-volatile flavor substances provides new insights for breeding Scylla paramamosain

The farming of Scylla paramamosain with specific flavors has a higher commercial value, and the flavors are related to the integrated farming environment and non-volatile flavor substances, while the survival environment is one of the important ways to source gut microorganisms in the organism. In this study, the levels of dominant taxa in the gut flora of S. paramamosain from Mong Cai, Vietnam (VN), Taishan City, Guangdong Province (TS) of China, and Ninghai County, Ningbo City (NB) Zhejiang Province of China converged with those of S. paramamosain from Sanmen County, Ningbo City (CK1, CK2, and CK3) at 28 d of domestication. The top 15 genera with the highest abundance of VN, TS, and NB gut flora were the same as CK1, CK2, and CK3, but with different percentages, and gradually converged to CK1, CK2, and CK3, respectively, at 28 d of domestication. Correlation between intestinal flora and non-volatile flavor substances in the hepatopancreas at the percentage level of relative abundance of bacterial genera found that above 28 d of domestication, Muribaculaceae, Psychrilyobacter, Clostridia_vadinBB60_group, Halarcobacter Carboxylicivirga, Sediminispirochaeta may be the most important genera affecting flavor amino acids of VN. Sediminispirochaeta, Carboxylicivirga, Halarcobacter, Photobacterium, ZOR0006, Psychrilyobacter, and Pseudomonas may be the most important genera affecting flavor amino acids of NB. Sediminispirochaeta, Carboxylicivirga, Halarcobacter, Photobacterium, ZOR0006, Vibrio, and Sphingomonas may be the most important genera affecting flavor amino acids of TS. These results show that the intestinal flora structure of crabs from different areas were domesticated in the same area for at least 28 d before they converged to that of the domesticated crab, and the most important genera affecting the flavor amino acids of TS, VN, and NB were also identified. The results of this study provide a reference and basis for the technique of directional cultivation of the flavor quality of the crab.