Dietary Ascorbic Acid Requirement of Juvenile Tilapia Oreochromis niloticus×O. aureus.

Abstract

A 14-week growth study was conducted to estimate the optimal ascorbic acid requirement in diets for hybrid juvenile tilapia Oreochromis niloticus×O. aureus. Purified diets with seven levels (0, 40, 60, 80, 100, 125, 150, and 200mg/kg diet) of supplemental L-ascorbic acid were pelleted and fed to 1.12±0.11g tilapia. Results indicated that fish fed diets lacking or low (40mg/kg) supplementary ascorbic acid had poor growth, feed conversion ratio (FCR), and protein efficiency ratio (PER); low ascorbic acid contents in the liver and body, also low haematocrit values in the blood. Deficiency of ascorbic acid resulted in a mortality of 37.78%. Weight gain analyzed by broken line regression indicated that the dietray ascorbic acid requirement for maximal growth in tilapia is 79mg/kg.