Abstract

A 56-day feeding experiment was conducted to determine the effects of modulated dietary gelatinized maize starch with protein level on the growth and feed utilization of juvenile Oreochromis niloticus. Four experimental diets (G16P28, G21P26, G26P23, and G34P25) contained gelatinized cornstarch at gradual incorporation level of 30%, 40%, 50%, or 60%, as replacement for fishmeal component of the control diet (G0P35). Final body weight and specific growth rate (SGR) were highest in fish fed control diet and diet containing 16% of gelatinized cornstarch and 28% of protein (G16P28). Feed conversion ratio was significantly influenced by the different dietary treatments (P < 0.05), with higher values obtained in fish fed G31P21 diets. Protein gain and lipid gain increased with increasing dietary gelatinized cornstarch level in linking to decrease of nitrogenous losses and net energy retention indicating protein-sparing effect of gelatinized cornstarch in tilapia diet. The whole-body proximate composition was significantly affected by the different treatments. In view of the growth results and the economic evaluation, inclusion of gelatinized starch has substantially reduced the cost of feed and increased economic profitability.

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