Dietary administration of Pleurotus ostreatus polysaccharides (POPS) modulates the non-specific immune response and gut microbiota diversity of Apostichopus japonicus

Abstract

Pleurotus ostreatus polysaccharides (POPS) can modulate the growth, immune response, and anti-inflammatory and antioxidant properties of mammals and aquatic animals. However, there has been no report about the effect of POPS on the innate immunity, growth and gut microbiota of A. japonicus to date. Here, we explored the relationship between dietary administration of POPS and the innate immunity or gut microbiota of A. japonicus. The results showed that after dietary administration of POPS, although there was no significant effect on the visceral wall ratio, weight gain or specific growth rate of A. japonicus, the activity of antioxidant and immune-related enzymes changed in A. japonicus. Moreover, there were differences in gut microbial diversity at multiple taxonomic levels in A. japonicus receiving dietary POPS supplementation. The dominant populations of gut microbiota in A. japonicus were Proteobacteria and Bacteroidetes at the phylum level. Interestingly, after dietary POPS supplementation, the relative abundance of Proteobacteria was reduced, while the relative abundance of Chloroflexi was increased. PCA and PCoA showed that the POPS3 group had no significant overlap with the other groups. LEfSe analysis showed that the POPS3 group differed from the other groups in terms of the gut microbes at many different taxonomic levels. Therefore, we speculated that dietary administration of POPS could modulate the innate immune response and gut microbiota diversity of A. japonicus. Taken together, the current results provide a foundation for greater understanding of the interaction between gut microbiota and innate immunity in A. japonicus.