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.