Dietary Bacillus subtilis HGcc-1 improves the growth performance, α-amylase and lipase activities, immunity and antioxidant capacity, intestinal microbiota, and heat stress resistance in Pacific white shrimp (Litopenaeus vannamei)

This study aimed to investigate the effects of B. subtilis HGcc-1 supplementation on the growth performance, immunity response, antioxidant capacity, intestinal microbiota and heat stress resistance of Litopenaeus vannamei. The results showed that B. subtilis HGcc-1 increased the activities of alpha-amylase and lipase and the activities of acid phosphatase and alkaline phosphatase, significantly decreased malondialdehyde content and significantly increased the activities of total antioxidant capacity, glutathione S-transferase, total superoxide dismutase, the expression levels of immune-related genes Toll and prophenoloxidase as compared to the control. Analysis of the intestinal microbial revealed that a significant increase in the relative abundance of Firmicutes, such as Lactococcus. Conversely, there was a decrease in the relative abundance of Proteobacteria, such as Vibrio and Shewanella. Furthermore, B. subtilis HGcc-1 supplementation may help alleviating heat stress injury in shrimp by modulating the Hippo signaling pathway. In summary, this study provided a valuable insight into the functional benefits of B. subtilis HGcc-1 supplementation in shrimp, offering a theoretical basis for its practical application in aquaculture.