Dietary supplementation with chondroitin sulfate improved the growth, immunity, and intestinal microbiota structure of Penaeus monodon

The research was designed to evaluate the influences of dietary chondroitin sulfate (CS) on the growth, immunity and intestinal community of Penaeus monodon (P. monodon). Shrimp (1.88 ± 0.17 g) were randomly divided into four treatment and fed with diets enriched with 0.0%, 0.2%, 0.5% and 1.0% CS for 56 days. The results showed that diets with 0.5% and 1.0% CS significantly improved the weight gain (WG), specific growth rate (SGR) and survival rate of P. monodon (p < 0.05). Intramuscularly, Vibrio harveyi (V. harveyi), white spot syndrome virus (WSSV) and decapod iridescent virus 1 (DIV1) were injected respectively at the end of the feeding trial. The results showed that dietary supplementation with 0.5% CS can improve the survival rate of V. harveyi-infected P. monodon, dietary supplementation with 1.0% CS can improve the survival rate of DIV1-infected P. monodon, and dietary supplementation with 0.5 and 1.0% CS can prolong the survival time of WSSV-infected P. monodon. To further investigate the role of CS in antiviral, the P. monodon fed with 0.0% and 1.0% CS were injected with PBS and DIV1. Plasmic and intestinal samples were then collected for enzyme activity and microbiome analysis. The results showed that the activities of immune enzymes in 1.0% CS-fed P. monodon were higher than those in 0.0% CS-fed P. monodon (p < 0.05), including lysozyme, catalase and superoxide dismutase, regardless of whether they were infected with DIV1 or not. After infection with DIV1, the activities of digestive enzymes of 1.0% CS-fed P. monodon showed no significant change (p > 0.05), while the activities of digestive enzymes of 0.0% CS-fed P. monodon were significantly increased (p < 0.05). Illumina MiSeq high-throughput sequencing revealed 24 major taxa of bacterial phyla in the intestine of P. monodon. Notably, after infection with DIV1, the abundance of Vibrio was significantly increased in the 0.0% CS-fed P. monodon while there was no significant change in the 1.0% CS-fed P. monodon. Overall, dietary supplementation with CS could effectively improve the growth and immune enzymes activities in P. monodon and stabilize the activities of digestive enzymes, avoid potential pathogens infection, and improve the survival rate and survival time of pathogen infection in P. monodon.