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This study was to investigate the effects of Alpinia officinarumHance stems and leaves extract (AOE) on the growth, non-specific immunity, intestinal microflora of shrimp (Litopenaeus vannamei). A total of 540 juvenile L. vannamei(2.69 ± 0.03 g) were randomly divided into six groups, and feed experiment with diet supplement of 0 g/kg (CG), 0.1 g/kg (AO-1), 0.2 g/kg (AO-2), 0.3 g/kg (AO-3), 0.5 g/kg (AO-4) and 0.7 g/kg(AO-5) AOE was carried out for 8 weeks, respectively. Compared with the control group (CG), the WGR and SGR of the AO-1, AO-3, and AO-4 groups were significantly increased. Crude protein content in the muscle of L. vannameiin AO-2 was significantly increased, while the water content was significantly decreased. The crude lipid content of each extract group was significantly decreased. Compared with the control group, activities of GSH-Px, SOD, and T-AOC in the cell-free hemolymph of AO-3 group were significantly enhanced, and the MDA content of each extract group was significantly decreased. Activities of CAT, SOD, and T-AOC in the hepatopancreas of AO-2 group were significantly increased. Gene expression levels of lvcat, lvgsh-px,and lvmn-sodin AO-3 group were obviously higher than those in the control group, while lvpropoexpression was dramatically higher in AO-2 and AO-3 groups. Moreover, AOE addition in feed changed the composition and species abundance of intestinal microflora of L. vannameiat phylum and genus levels. Through α diversity analysis, the biodiversity of the flora was improved, while β diversity analysis changed the similarity of the flora between the control and addition groups. Therefore, addition of 0.2–0.3 g/kg AOE could improve the growth, immunity and optimize the composition of intestinal microorganisms of L. vannamei.

The current study was conducted to determine the effects of dietary Radix bupleuriroot extract (RBE) on the growth performance, muscle composition, immune responses, and microcystin-LR (MC-LR) stress resistance of juvenile red claw crayfish (Cherax quadricarinatus). Crayfish (0.28 ± 0.02 g) were fed experimental diets containing graded RBE levels as 0 (Diet 1), 0.2 (Diet 2), 0.4 (Diet 3), 0.6 (Diet 4), 0.8 (Diet 5) and 1.6 (Diet 6) g/kg RBE for 8 weeks. The results showed that specific growth rate (SGR) and weight gain rate (WGR) were significantly increased in the Diet 4 and Diet 5 groups. The content of muscle crude protein was significantly increased in the Diet 4 and Diet 5 groups, and the crude lipid content was significantly decreased in the Diet 5 group. Dietary RBE did not alter the structure of the hepatopancreas. Total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activities in hepatopancreas and plasma were significantly increased in Diet 4 and Diet 5 groups compared to the control group, while the malondialdehyde (MDA) content in hepatopancreas and plasma was significantly decreased in the Diet 5 group. Plasma alkaline phosphatase (AKP) activity was significantly higher in the Diet 3, Diet 4, Diet 5 and Diet 6 groups. Hepatopancreas and plasma PO activities were significantly increased in Diet 4 and Diet 5 groups. The mRNA levels of extracellular copper/zinc superoxide dismutase (ecCu, Zn-SOD), hemocyanin, C-type lysozyme (C-LZM), GPx, and selenium-dependent glutathione peroxidase (Se-GPx) were significantly up-regulated in the hepatopancreas of crayfish fed Diet 5 than those of the control group. After MC-LR challenge, the survival rates of crayfish in the Diet 4 and Diet 5 groups were significantly higher than the control group. The findings suggest that 0.6–0.8 g/kg of RBE can improve growth and muscle composition and enhance immunity and microcystin-LR resistance.