Abstract

An 8 week feeding trial was carried out to determine the effects of gradual incorporation of gelatinized corn starch modulated with dietary protein on the growth and feed utilization of juvenile Oreochromis niloticus.
Four experimental diets (G16P28, G21P26, G26P23 and G34P25) contained gelatinized corn starch at gradual incorporation level of 30%, 40%, 50% or 60%, as replacement for fishmeal component of the control diet (G0P35). The highest final body weight (FBW) and Specific growth rate (SGR) were obtained with fish diets control diet (G0P31) and diet G16P28 (Containing 16% of gelatinized corn starch and 28% of protein).
Feed conversion ratio (FCR) was significantly different among treatments (p < 0.05), with the highest values obtained in fish fed with diets G31P21. Protein gain (PG) and lipid gain (LP) increased with increasing dietary gelatinized corn starch level in linking to decrease of Nitrogenous losses (NL) and Net energy retention (NER) indicating protein-sparing effect of gelatinized corn starch 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.

Key words: Oreochromis niloticus, Gelatinized corn starch, feeding, Growth, body composition