Effects of dietary calcium and cholecalciferol on weight gain and mineral composition of the blue tilapia

Abstract

Interactions of dietary calcium and cholecalciferol (vitamin D3) were evaluated with fingerling blue tilapia using a 2 x 2 factorial design. Four purified diets were formulated to contain 34% crude protein from egg albumin and 3.20 kcal available energy/g. The basal diet (0.02% Ca) was supplemented with either 0 or 0.75% Ca (from CaC'2-2H,O) and 0 or 2,000 IU vitamin D3/kg in a factorial arrangement. Experimental diets were fed in triplicate to groups of blue tilapia initially averaging 2.30 ︢0.09 g in 38-1 aquaria receiving water with 0.1 mg Ca/l for a period of 36 weeks. Significantly (P < 0.05) greater weight gain, bone and scale calcium, as well as bone and scale phosphorus values were observed for fish fed the calciumsupplemented diets as compared to fish fed the diets without supplemental. calcium. Supplementation of vitamin D3 produced some significant differences in these parameters, however; the differences were not consistent for all sampling periods. Based on these results, it is concluded that dietary calcium had the most profound effects on growth and mineral composition of the blue tilapia and effects of vitamin D3 were more subtle.