Intestinal health deficits in precocious Chinese mitten crab (Eriocheir sinensis): Integrated exploration of feeding behavior, histopathology, and microbiota

Abstract

Sexual precocity is a common problem in the aquaculture of Chinese mitten crabs (Eriocheir sinensis), and can reduce the aquaculture performance. The healthy intestines play a vital role in sustaining aquaculture performance. Therefore, this study investigated the effects of sexual precocity on the feeding behavior, histopathology, and intestinal microbiota of E. sinensis. Based on the data obtained, precocious crabs showed a longer feeding response time (136.51 ± 41.51 min) and a shorter feeding duration (36.46 ± 11.86 s) than non-precocious crabs (13.37 ± 3.96 min and 49.33 ± 21.95 s). Meanwhile, histological abnormalities were also observed in the intestines of precocious crabs. The histopathological results of the precocious crabs’ intestine revealed a larger intestinal diameter (1.113 ± 0.071 mm) and luminal area (0.621 ± 0.037 mm2), a thicker peritrophic membrane (13.870 ± 3.236 μm), as well as broken-down hindgut glands and disordered-arranged columnar epithelial cells. 16S rRNA gene sequencing analysis revealed deeper changes related to intestinal health in precocious crabs, with greater abundance of potentially pathogenic bacteria such as Vibrio and Roseimarinus. The potentially pathogenic bacteria in precocious crabs’ intestine such as Mycoplasmataceae and Alphaproteobacteria were found in greater abundance, while beneficial bacteria including Rhizobiales and ZOR0006 were lower in abundance. Univariate correlation analysis revealed that Rhizobiales and ZOR0006 had negative correlations with various potentially pathogenic bacteria including Vibrio and Roseimarinus. Based on the determination of microbiota in the water environment and SourceTrack analysis, the results indicated a decline in the proportion of intestinal microbiota derived from the water environment in precocious crabs. In conclusion, precocious crabs exhibit poorer intestinal health, which exacerbates aquaculture risks.