Effects on growth performance and immunity of after high temperature stress.

To investigate the impact of the effect of high temperature stimulation on larvae after a certain period of time, five experimental groups were established at different temperatures. Then, the under high temperature stress was fed at 30°C for 70 days. After that, the growth index of the was counted and analyzed. In terms of growth index, high temperature stress had significant effects on FCR, FBW, WGR, and SGR of ( 0.05). The SR increased after being stimulated by temperature ( 0.1). The study revealed that liver cells of were harmed by elevated temperatures of 36°C and 38°C. In the experimental group, the activities of digestive enzymes changed in the same trend, reaching the highest point in the 32°C group and then decreasing, and the AMS activity in the 38°C group was significantly different from that in the 30°C group ( < 0.05). The activities of antioxidase in liver reached the highest at 34°C, which was significantly different from those at 30°C ( < 0.05). In addition, the expression levels of , , , and other genes increased in the experimental group, reaching the highest point at 34°C, and the expression level of the gene reached the highest point at 32°C, which was significantly different from that at 30°C ( < 0.05). However, the expression level of the gene decreased in the experimental group and reached its lowest point at 34°C ( < 0.05). The expression level of the gene increased with the highest temperature stimulus and reached its highest point at 38°C ( < 0.05). In the α diversity index of intestinal microorganisms in the experimental group, the observed species, Shannon, and Chao1 indexes in the 34°C group were the highest ( < 0.05), and β diversity analysis revealed that the intestinal microbial community in the experimental group was separated after high temperature stimulation. At the phylum level, the three dominant flora are , , and . and abundance increased at the genus level, but and abundance decreased. To sum up, appropriate high-temperature stress can enhance the immunity and adaptability of . These results show that the high temperature stimulation of 32°C-34°C is beneficial to the industrial culture of .