Dietary biotin requirement for maximum growth of juvenile grass shrimp, Penaeus monodon

A feeding trial was conducted to estimate the minimal dietary biotin requir ement for juvenile grass shrimp, Penaeus monodon. Purified diets with eight levels (0, 0.2, 0.5, 1.0, 3.0, 6.0, 10.0 and 20.0 mg/kg) of supplemental b iotin were fed to P. monodon (mean weight 0.26 +/- 0.01 g) for 8 wk. Each d iet was fed to three replicate groups of shrimp. Shrimp fed diets supplemen ted with biotin (0.2-20.0 mg/kg) had significantly (P < 0.05) higher weight gain, feed efficiency and protein efficiency ratio than those fed the unsu pplemented control diet. Weight gain was high in shrimp fed 3.0-10.0 mg bio tin/kg diet and lowest in shrimp fed less than or equal to 1.0 mg/kg diet. Hepatopancreatic biotin concentration in shrimp generally increased as diet ary biotin supplementation increased. Highest hepatopancreatic pyruvate car boxylase and acetyl CoA carboxylase activity were in shrimp fed diets with 10 and 20 mg biotin/kg and 3.0 mg biotin/kg, respectively. Weight gain perc entage and protein efficiency ratio of the shrimp analyzed by broken-line r egression indicated that the minimal dietary biotin concentration in growin g P. monodon is 2.0-2.4 mg/kg.