Genetic evaluation of a 15-year selection program for high growth in striped catfish Pangasianodon hypophthalmus

This study attempted to make a comprehensive genetic evaluation of a selective breeding program for striped catfish Pangasianodon hypophthalmus selected for high growth over 15 years from 2001 to 2015. Statistical analyses were carried out on 54,259 individual fish that were offspring of 554 sires and 926 dams (955 families in total). Both univariate and bivariate linear animal mixed models were used to estimate variance and covariance components for four groups of traits studied: (i) body traits (harvest body weight and standard length), (ii) carcass traits (fillet weight and fillet yield), (iii) fish body condition (condition index) and (iv) growth survival of each individual during grow-out phase. Medium to high heritability (0.31-0.54) were estimated for body traits, while carcass and condition index had medium heritability (0.17 to 0.20). Phenotypic and genetic correlations among body traits (weight and length) were high and close to one. The growth-related traits showed moderate and positive (i.e., favourable) genetic correlations with fillet yield (0.67-0.92) and condition index (0.28-0.49). Direct response to selection for high growth was 9.3% per generation. The selection program increased fillet weight and growth survival by 8.5% and 7.4%, respectively. However, there was insignificant correlated change in fillet yield (only 1.6%). Collectively, our results showed that there are substantial genetic variations in all traits studied and selection for high growth resulted in beneficial changes in fillet weight, fish body condition and survival during grow-out phase. The improved strain of striped catfish had 13.4% greater growth performance than their wild counterparts of the latest generation, suggesting that culture of the improved striped fish line may enhance productivity and economic return for small householder farmers and commercial producers.