Effects of diurnal temperature fluctuations on growth performance, energy metabolism, stress response, and gut microbes of juvenile mud crab Scylla paramamosain

A 51-day experiment was conducted to investigate the effects of diurnal temperature fluctuations (DTF) on growth performance, energy metabolism, stress response and gut microbiota of juvenile mud crab Scylla paramamosain. DTF affected the structure and function of gut microbes. The bacterial community changed with the intensification of DTF and alpha diversity continued to rise. Five biomarkers were identified, where Rhodobacterales and Rhodobacterac were significantly more abundant in the CT group, Campylobacterales,Vibrionales and erysipelotrichales were more abundant in the SF, MF and LF groups. In addition, SF also enhanced gut microbes interactions compared with other treatments. These results suggest that drastic environmental DTF reduced the growth and survival of young mud crabs, and the effect was mediated by energy metabolism, antioxidant pathways and gut microbes.

本研究开展了为期51天的实验，以探究昼夜温度波动（diurnal temperature fluctuations, DTF）对拟穴青蟹（Scylla paramamosain）幼蟹生长性能、能量代谢、应激反应及肠道菌群的影响。昼夜温度波动可影响肠道微生物的结构与功能：随着波动强度的加剧，细菌群落结构发生改变，α多样性持续升高。本研究共鉴定出5种生物标志物，其中红杆菌目（Rhodobacterales）与红杆菌科（Rhodobacteraceae）在CT组中丰度显著更高；弯曲杆菌目（Campylobacterales）、弧菌目（Vibrionales）及丹毒丝菌目（Erysipelotrichales）则在SF、MF与LF组中丰度更高。此外，相较于其他处理组，SF组还可增强肠道微生物间的互作关系。上述结果表明，剧烈的环境昼夜温度波动会降低拟穴青蟹幼蟹的生长性能与存活率，且该效应可通过能量代谢、抗氧化通路及肠道菌群实现介导。