Effects of salinity stress on the growth performance, health status, and intestinal microbiota of juvenile Micropterus salmoides

Soil salinization has become a increasingly serious problem due to the continuous deterioration of the global environment. A large amount of land is unused due to salinization, and this represents a large waste of resources. Micropterus salmoides is a freshwater fish that has become increasingly popular among consumers in recent years. We investigated the effects of salinity stress on the growth performance, health status, and intestinal microbiota of juvenile M. salmoides. >480 juveniles were reared in tanks at salinity levels of 0, 5‰, 10‰, and 15‰ for 6 weeks. The weight gain rate and specific growth rate significantly decreased as salinity increased. Superoxide dismutase (SOD) activity significantly increased in the 5‰ salinity group. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), acid phosphatase (ACP), alkaline phosphatase (AKP) activity and total antioxidant capacity (T-AOC) significantly increased when the salinity was 15‰ (P