Effects of dietary mineral supplements on the growth of fingerlings of Labeo rohita (Hamilton) and Labeo bata (Hamilton)

Trials were made in 400-liter outdoor cement tanks to evaluate the effects of dietary supplementation of minerals for the growth of the carps Labeo rohita (Hamilton) and Labeo bata (Hamilton). Three dietary conditions were used in the trial: a diet containing 2% mineral supplement (T1), a diet devoid of mineral supplement (T2) and a diet devoid of mineral supplement but with an exogenous supply of cultured live plankton in 5ml concentrated suspension (containing 800-1220 zooplankton) for six days a week (T3). Water quality parameters did not show any significant variation during the feeding trials. Dietary mineral supplement rendered a significant increase in the growth of Labeo bata but not of Labeo rohita. Exogenous supply of zooplankton did not produce any significant impact on the growth for any of these two species of fish.