Morphometric traits as selection criteria for carcass yield and body weight in Nile tilapia (Oreochromis niloticus L.) at five ages

Faster growth has been the primary goal of the few existing selection programs for Nile tilapia. However, carcass yield (CY) is a major factor for tilapia production chain efficiency. The use of indirect selection for CY is vital because direct data collection is only possible after slaughter. The aim of this study was to estimate heritability and correlation between body weight (BW), CY, height (H), width (W) and corrected length (CL) as functions of standardized ages in Nile tilapia. Bivariate animal model analyses were conducted for all traits at five ages (119, 147, 175, 203 and 231days) and 16 distinct models for fixed and random effects were compared. Heritability estimates through all ages varied from 0.20 to 0.94 for CY, 0.21 to 0.44 for BW, 0.21 to 0.40 for H, 0.13 to 0.80 for W and 0.19 to 0.48 for CL. All genetic correlation estimates were positive, and those between BW and morphometric traits (0.66–1.00) at all ages, CY and H (0.71) at 119days, and CY and CL (0.58) at 231days were high. These results highlight the possibility of achieving high genetic gains with selection for any of these traits. These correlations indicate the possibility of achieving indirect genetic gains for CY and BW by the selection of morphometric traits. Novelties on direct and indirect selection for carcass yield. •Indirect selection for slaughter traits may be a suitable way to promote genetic improvement.•There is still little information about genetic parameters for carcass yield in Nile tilapia.•Estimate of correlations between morphometric traits, body weight and carcass yield at five ages.•Selection for morphometric traits leads to indirect genetic gains for carcass yield and body weight.