Meta-analysis of genetic parameters for productive traits in Nile tilapia (Oreochromis niloticus)

The advances in the production traits of Oreochromis niloticus are due to the development of genetically superior broodstock animals. Understanding the genetic variability of fish stocks is crucial to any animal breeding program. The aim of this study was to perform a meta-analysis of genetic parameters that considers the variability between studies for economically important traits in the Nile tilapia (Oreochromis niloticus) production. The final dataset from literature review contained 226 estimates of heritability and 53 estimates of genetic correlation across 37 peer-reviewed articles published between 2002 and 2022. Weighted genetic parameter estimates were obtained by fitting a random effect model for all traits studied. Heterogeneity across studies were assessed using the Q statistic and I2 index. Heritability estimates ranged from low to moderate magnitude, indicating that a greater response to selection is expected for body length (0.37), body weight (0.29), body width (0.28), and daily weight gain (0.28), compared to the other traits, body height (0.25) and fillet yield (0.19). Genetic correlations ranged from moderate to high magnitude (0.47 to 0.94), which suggests that part of expression of traits is regulated by the same gene groups. The meta-analysis study provided reliable genetic parameter estimates and these findings may be served as the baseline reference for new Nile tilapia (Oreochromis niloticus) breeding programs.