Based on the microbiota-intestine-brain axis to revel the toxicity mechanism of Chinese mitten crab (Eriocheir sinensis) exposed to heat stress

Climate warming and frequent extreme high temperatures are global issues, and aquatic poikilotherms are facing severe heat stress challenges in this environment. The Chinese mitten crab (Eriocheir sinensis) is a typical aquatic poikilothermal crustacean, which is sensitive to high temperature. However, the toxic effects of heat stress on E. sinensis and its association with the microbiota-intestine-brain axis are still unclear. This study evaluated the effects of heat stress on neurotoxicity, intestinal health, microbial diversity and metabolic profile of juvenile E. sinensis to revealed the potential mechanism of ''microbiota-intestine-brain axis''. The results showed that heat stress significantly up-regulated the apoptosis-related genes in the cranial ganglia of juvenile E. sinensis, and the mRNA expression of neurotransmitter-related receptor were abnormally changed significantly. On the other hand, compared with the control group, teat stress significantly induced intestinal damage, mainly manifested as the diamine oxidase activity in serum and histamine content in intestine increased significantly, and produced a significant oxidative stress response. In addition, the diversity and abundance of intestinal microbiota was abnormal changes in juvenile E. sinensis exposed to heat stress, and the significantly changed microbiota were closely related to the production of neurotransmitters and neuromodulators. Moreover, heat stress caused significant changes in the intestinal metabolic profile of juvenile crabs, mainly involving amino acid metabolism and lipid metabolism pathways. The correlation analysis of intestinal microbiota and metabolic profile showed that the abnormal changes of metabolites were closely related to the different abundance of intestinal microbiota. Therefore, this study showed that heat stress could cause neurotoxicity, intestinal damage, microbiota disorder and metabolic profile abnormalities in E. sinensis, and preliminarily revealed the possible mechanism of microbiota-in.