Effects of dietary supplementation of Achyranthes aspera extract on growth performance, digestibility, innate immunity, antioxidant capacity, and disease resistance of juvenile Pacific white shrimp, Penaeus vannamei

A supplemental effect of Achyranthes aspera extract (200 mg/kg phytosterol) in diets was evaluated for Pacific white shrimp ( Penaeus vannamei ) on growth performance, digestibility, innate immunity, antioxidant capacity, and disease resistance against Vibrio parahaemolyticus . A fish meal and soybean meal‐based control diet (Con; protein 38.0% and lipid 8.7%) was formulated and five other diets were prepared by adding A. aspera extract into Con diet to be 0.05, 0.1, 0.2, 0.4, and 0.8 mg phytosterol/kg concentration (designated as P05, P10, P20, P40, and P80, respectively). Three replicate groups of 30 shrimp (initial body weight, 0.40 ± 0.001 g) per diet were randomly assigned into 18 acrylic tanks (240 L) and fed one of the diets for 53 days. The growth performance and feed utilization efficiency were significantly higher in shrimp fed P20 and P80 diets than in shrimp fed Con and P10 diets. The dietary phytosterol supplementation improved non‐specific immune response, antioxidant capacity, and apparent digestibility coefficients of dry matter and protein of shrimp. The IGF‐binding protein gene expression was also upregulated with dietary phytosterol supplementation. During the challenge test, the disease resistance of shrimp was significantly enhanced against V. parahaemolyticus when shrimp were fed P20 diet. These results indicate that A. aspera extract could be used as a functional feed additive for the improvements in the growth performance, feed efficiency, innate immunity, antioxidant capacity, digestibility, and disease resistance of the shrimp. The optimum dietary inclusion level of the phytosterol seems to be 0.2–0.4 mg/kg diet.