The present study investigated the effect of AZOMITE–chitosan chelate (ACC, formed by the chelation of chitosan and AZOMITE, a hydrated sodium calcium aluminosilicate mineral enriched with rare earth elements) on growth performance, hepatopancreas and intestinal histology, gut microbiology and disease resistance of Pacific white shrimp, Litopenaeus vannamei . Four diets were prepared by adding 0 mg/kg (ACC0), 750 mg/kg (ACC750), 1500 mg/kg (ACC1500), and 3000 mg/kg (ACC3000) to the basal diet, and then fed to shrimp (1.60 ± 0.10 g) for 56 days followed by pathogenic bacteria challenge test. The weight gain of shrimp tended to rise with the increasing ACC addition, and the weight gain of ACC3000 group was significantly higher than that of the control group ( P 0.05). In hepatopancreatic digestive enzyme activity and hemolymph biochemical indexes, the protease activity of ACC3000 group and the hemolymph activities of acid phosphatase (ACP), alkaline phosphatase (AKP),and superoxide dismutase (SOD) of all ACC groups were significantly higher than those of the control group ( P < 0.05),whereas catalase (CAT) activity was significantly increased in the ACC1500 and ACC3000 groups. In hepatopancreatic and intestinal histology, the villus height of the ACC750 group and the muscle layer thickness of the ACC3000 group were significantly higher than those of the control group ( P < 0.05). No significant difference was observed in the appearance of hepatopancreatic tissue sections among all the groups, except that the number of R cells was significantly higher in ACC groups than that in the control group ( P < 0.05). Compared with the control group, the relative abundance of Bacillota was significantly higher in the ACC1500 group ( P < 0.05), and the relative abundance of Actinomycetes phylum and Mycobacterium, Arenimonas were significantly lower in the ACC1500 and ACC3000 groups ( P < 0.05 ). In Vibrio parahaemolyticus infection test, the cumulative mortality of the ACC3000 group was noticeably lower than that of the control group ( P < 0.05). In conclusion, dietary addition of 3000 mg/kg ACC improved the growth performance and antioxidant capacity of Litopenaeus vannamei , and enhanced the resistance against Vibrio parahaemolyticus infection. • Dietary supplementation of AZOMITE-chitosan chelate improved growth performance of Litopenaeus vannamei . • Antioxidant capacity was enhanced by AZOMITE-chitosan chelate. • AZOMITE-chitosan chelate (3000 mg/kg) significantly improved resistance to Vibrio parahaemolyticus infection of Litopenaeus vannamei .
Wang et al. (Thu,) studied this question.