Dietary astaxanthin modulated the performance, gastrointestinal histology, and antioxidant and immune responses and enhanced the resistance of Litopenaeus vannamei against Vibrio harveyi infection

Abstract Astaxanthin (AX) is one of the commonly used feed supplements to enhance growth performance and provide antioxidant immune functions several aquatic animals. In current study, juveniles white-leg shrimp ( Litopenaeus vannamei ) with mean initial weight 0.340 ± 0.041 g were fed diets supplemented 0 (control), 25, 50, 100, 200 mg/kg for 8 weeks. At end feeding trial, shrimps exposed Vibrio harveyi , their mortality rates observed additional 10 days. The indices in AX-fed groups significantly P < 0.05) higher than what control group. Dietary AX stimulated final weight, gain, specific rate optimum levels achieved at 100–200 mg AX/kg feed. Furthermore, AX-enriched enhanced intake more diet, amount had no effects on conversion ratios. comparison group, animals villi length, width, absorption area values treatments. Moreover, intestinal morphometry especially its crypt, both internal external tunica muscularis, submucosal tissues did not show any inflammatory and/or degenerative changes shrimp. dietary escalating linearly quadratically activities serum superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), increased total capacity reduced glutathione. addition, malondialdehyde decreased animals, highest group (without AX). expression cMn-SOD CAT GPx genes upregulated hepatopancreas L. (especially 200-mg/kg treatment) as compared diet. immunity treatments (hematocyte count, protein, lysozyme, phagocytic activity, phenoloxidase) increased. This study revealed antibacterial activity against V. abundance. After bacterial challenge, relative percentage survival, treatment diet (82.7%). findings demonstrate that (100–200 feed) was effective enhancing growth, status, response, increasing resistance infection.