Estimation of the dietary riboflavin required to maximize tissue riboflavin concentration in juvenile shrimp (Penaeus monodon).

The riboflavin requirements of marine shrimp (Penaeus monodon) were evaluated in a 15-wk feeding trial. Juvenile shrimp (initial mean weight, 0.13 +/- 0.05 g) were fed purified diets containing seven levels (0, 8, 12, 16, 20, 40 and 80 mg/kg diet) of supplemental riboflavin. There were no significant differences in weight gains, feed efficiency ratios and survival of shrimp over the dietary riboflavin range. The riboflavin concentrations in shrimp bodies increased with the increasing vitamin supplementation. Hemolymph (blood) glutathione reductase activity coefficient was not a sensitive and specific indicator of riboflavin status of the shrimp. The dietary riboflavin level required for P. monodon was found to be 22.3 mg/kg diet, based on the broken-line model analysis of body riboflavin concentrations. Shrimp fed unsupplemented diet (riboflavin concentration of 0.48 mg/kg diet) for 15 wk showed signs of deficiency: light coloration, irritability, protuberant cuticle at intersomites and short-head dwarfism.