RELATIVE GROWTH AND ALLOMETRIC COEFFICIENTS OF BODY COMPONENTS OF STRAINS OF NILE TILAPIA(Oreochromis niloticus)

Abstract

This experiment was carried out in the fish production facilities of the Federal University of Lavras, MG – Brazil, to study relative growth and allometric coefficients of body components on body weight of Nile tilapia. Fishes, weighing between 150 and 790g, were randomly sampled during every period of growing, have been 93 of the Chitralada strain and 78 of the Supreme. After 24 hours of fasting, the fishes were insensibilized (thermal shock), slaughtered (anoxia), weighed and dissected to obtain body components weights. The allometric equation y = axb of Huxley (1932) and the statistic t (á = 0,01) were used for hypothesis test of b=1 and than the growth of the body components parts were classified in: isogonic (b=1), later (b>1) and early (b<1). The scale and fins, head and viscera didn’t show significant difference between the strains and obtained, respectively, allometry coefficient b=1, b>1 and b<1. Chitralada strain showed early growth for carcass and filleting remnants, late for skin andisogonic for fillet. On the other hand, Supreme showed isogonic growth for carcass, skin and filleting remnants and late growth for fillet, that is desirable for meat production. KEY WORDS: Allometry, fillet, fish, Supreme, Thai.