Dietary vitamin K requirements of Pacific white shrimp, Penaeus vannamei at post-larval and juvenile stages

Abstract

This study investigated vitamin K3 (VK3) requirement of Pacific white shrimp, Penaeus vannamei at different growth stages through two feeding trials. Experimental diets were prepared to contain VK3 by 0, 50, 100, 200 and 400 mg/kg (designated as M0, M50, M100, M200 and M400, respectively). For the first experiment (Exp-1), post-larval (1.32 ± 0.01 mg) were fed the diets six times daily for 49 days and for second experiment (Exp-2), juveniles (0.45 ± 0.01 g) were fed the diets six times daily for 52 days. At the end of both feeding trials, VK3-supplemented groups had significantly higher growth performance than M0 group, except for M50 group in Exp-1. Lipase and trypsin activities were significantly enhanced by VK3-supplementation, except for lipase in M50 of Exp-1. In both experiments, aspartate aminotransferase levels were significantly higher in M100–M400 groups than in M0, whereas alanine aminotransferase levels were significantly elevated in all VK3 supplemented groups in Exp-1 and in M400 group in Exp-2. Superoxide dismutase activity was significantly increased in M400 group in Exp-2, while glutathione peroxidase activity was elevated in M400 group of Exp-1 and in all VK3-supplemented groups of Exp-2 than in M0 group. In both experiments, insulin-like growth factor (IGF)-1 and IGF-BP genes were upregulated by the dietary VK3 supplementation. Ecdysone receptor (EcR) and retinoid X receptor expressions were significantly upregulated in M50–M200 groups than in M0 group of both trials. SOD expression was significantly upregulated in M50 group than in M0 for both trials, whereas GPx expression was higher in M50 and M100 groups of Exp-1. Prophenoloxidase was significantly upregulated with increasing dietary VK3 levels in Exp-2. Broken-line regression analysis indicates that VK3 requirement would be 107 mg/kg for the shrimp at post-larval stage and 40.3 mg/kg for the shrimp at juvenile stage.