Responses to selection for performance traits in Nile tilapia

Abstract:

The objective of this work was to estimate genetic parameters and direct and indirect responses to selection for performance traits in Nile tilapia (Oreochromis niloticus), as well as to evaluate the impact of selection on genetic gain. Information about Nile tilapia, under selection in a genetic improvement program, grown in a net-tank system, from 2008 to 2010, was used. Heritability and genetic correlations for the traits daily weight gain, and, immediately after catching, weight, width, height, and trunk length were estimated, besides the genetic gains obtained by the estimation of genetic tendencies and of the responses to selection for these traits. Heritability estimates were around 30%. The estimates of genetic and rank correlations had high magnitude. The direct genetic gain for daily weight gain was 7.9, 5.18, and 9.43% in 2008, 2009, and 2010, respectively. The genetic gains obtained from the genetic tendencies were 6.36, 6.30, 1.62, 1.65, and 1.51%, respectively, for daily weight gain, and trunk weight, width, height, and length. The increased growth rate through selection positively impacts performance traits in Nile tilapia.

Index terms:
Oreochromis niloticus; genetic correlation; genetic gain; indirect selection; genetic tendency