Body composition of Nile tilapias (Oreochromis niloticus) in different length classes

Abstract

The objective of this research was to evaluate the body composition of Nile tilapias in different length classes of Thai and Commercial strains, being the latter derived from the GIFT program (Genetically Improved Farmed Tilapia) regrdingthe levels of moisture, crude protein, ether extract, ash and energy. The fish were cultivated in cages in a dam in Presidente Prudente, SP –Brazil. Astheanimalsgrew, fish sampled randomly from each strain were weighed and measured in length. The body composition showed differences between the strains in the levels of moisture, carbohydrates, ether extract and energy as the fish grew(P<0.05). The content of protein and ash was similar forbothstrains, but the percentage of ash increased with the fish growth. Adecrease in the percentageof moisture and increasein thepercentageof ether extract and in the energetic content were observed in the larger class length. Differences in rates of growth of tilapia strains influence the metabolic rates of mobilization, particularly of water and ether extract, changing the dynamics of deposition of these elements and the energy content.