Quantification of vitamin C requirement for juvenile hybrid tilapia, Oreochromis niloticus X Oreochromis aureus, with L-ascorbyl-2-monophosphate-Na and L-ascorbyl-2-monophosphate-Mg

A growth experiment was conducted to quantify the level of L-ascorbyl-7-monophosphate-Na (C2MP-Na) to satisfy the dietary vitamin C requirement for juvenile hybrid tilapia. L-Ascorbyl-2-monophosphate-Mg (C2MP-Mg) was also included in the study for comparison. Purified diets with six levels of ascorbic acid (0, 30, 50, 70, 90 and 120 mg/kg diet) from either supplemental C2MP-Na or C2MP-Mg were each fed to triplicate groups of fish (mean initial weight: 1.22 +/- 0.07 g) for 8 weeks. Fish fed greater than or equal to 38.97 mg C2MP-Na/kg diet and greater than or equal to 22.92 mg C2MP-Mg/kg diet gained significantly (P < 0.05) more body weight than fish fed the unsupplemented diet. Hepatic ascorbate concentrations in fish generally increased as the dietary ascorbate level increased. Results of the broken Line analysis indicated that the adequate dietary ascorbic acid From each source for growing fish is 63.4 mg of C2MP-Na/kg (equivalent to 15.98 mg of ascorbic acid/kg) diet and 40.5 mg of C2MP-Mg/kg (equivalent to 18.82 mg ascorbic acid/kg) diet, and it also indicated that C2MP-Mg was about 85% as effective as C2MP-Na in meeting the vitamin C requirement for tilapia. (C) 1999 Elsevier Science B.V. All rights reserved.