VITAMIN-C REQUIREMENTS OF THE SHRIMP PENAEUS-VANNAMEI

Two experiments were conducted to investigate vitamin C requirements of the shrimp Penaeus vannamei using L-ascorbyl-2-polyphosphate (APP) in semi-purified diets. Shrimp survival but not growth was significantly (P < 0.05) reduced by feeding vitamin C-deficient diets. Whole-body ascorbic acid (WBAA) content in shrimp increased as dietary vitamin C increased. After shrimp were fed a vitamin C-free diet for 3 weeks, the depletion levels for WBAA of shrimp were found to be 2.6 and 4.8 mug/g for shrimp with an initial weight of 0.1 and 0.5 g, respectively. Minimum dietary vitamin C levels required for normal survival of P. vannamei were estimated to be 120 mg ascorbic acid-equivalent (AAE)/kg diet for shrimp with an initial weight of 0.1 g and 41 mg AAE/kg diet for shrimp with an initial weight of 0.5 g. Dietary vitamin C levels of 120 and 90 mg AAE/kg were required for maintaining a normal WBAA content in shrimp with an initial weight of 0.1 and 0.5 g, respectively. These data indicated that dietary vitamin C requirement of P. vannamei decreased with increased size.