Aflatoxin B1 (AFB1) induced dysregulation of intestinal microbiota and damage of antioxidant system in pacific white shrimp (Litopenaeus vannamei)

Aflatoxins, especially aflatoxin B1 (AFB1), exert a substantial impact on the shrimp farming production, inducing disease with a gradual decline of reared shrimp stock quality and profitability, thus causing a significant problem in aquaculture systems. In order to investigate the influence of AFB1 on intestinal health and antioxidant system, we monitored the dynamic change of intestinal microbiota of pacific white shrimp (Litopenaeus vannamei) at 3-, 6-, 12-, 18-, 24- and 30-d after AFB1 challenge. Meanwhile, we determined the activities of several important antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and the content of malondialdehyde (MDA) in the intestines and hepatopancreas. The results showed that, the types of intestinal microbiota in the control group are more abundant than the experimental group both at the phyla level and genera level. At the phyla level, the relative abundance of Proteobacteria and Firmicutes in the experimental group increased obviously with the culture days extension, while the relative abundance of Bacteroidetes decreased. At the genera level, the relative abundance of Vibrio and Photobacterium in the experimental group increased evidently, while the relative abundance of Flavobacterium_sp_M and Tenacibaculum decreased. The CAT, SOD and GPX activities of intestinal and hepatopancreas were significantly higher in the experimental group than in the control group, and showed a tendency to increase first and then decrease as a whole while the content of MDA changes on the contrary. All above findings suggested that AFB1 could induce dysregulation of intestinal microbiota and damage of antioxidant system in pacific white shrimp (Litopenaeus vannamei).