Predicting Body Composition of Nile Tilapia (Oreochromis niloticus)

Abstract

Accurate prediction of proximate composition for a commercially cultured fish at a particular body weight could help to reduce overall feed waste, improve feed efficiency, and increase profitability. We studied the relationship between biochemical composition of Nile tilapia and its wet weight for the range of minimum and maximum body weight found in the published literature. We also tested the predictive value of regression equations. Logarithmic trends of the proximate composition showed a linear trend for tilapia up to 0.4 g. The trend formed a plateau for tilapia larger than 5 g. The slopes (b) for water, protein, fat, and ash contents as percent bodyweight were -0.008, 0.003, 0.003, and 0.002 respectively. The slopes were close to “0” and did not change significantly after removing data from fishes smaller than 5 g in all four cases. Mean percent error of water (-0.145) and protein (-0.769) showed no differences between them. A large percent error mean for fat (-39.179) suggested presence of variations in fat contents to whole body weight. Our findings suggested no significant changes in percent water and percent protein over the life-span of Nile tilapia partially rejecting the null hypothesis that percent composition of Nile tilapia varies over their lifetime.