Estimates of heritabilities and genetic correlations for growth and carcass traits in gilthead seabream ( Sparus auratus L.), under industrial conditions

Abstract

In this study, for the first time on gilthead seabream ( Sparus auratus L.), genetic parameters for growth and carcass traits were estimated at 509 days (harvest size), and for growth only at another three ages (130, 165 and 330 days). A total of 867 offspring from an industrial mass spawning of 66 broodstocks were analysed. Parental assignment was inferred using the RimA multiplex PCR designed by Navarro et al. [Navarro, A., Badilla, R., Zamorano, M.J., Pasamontes, V., Hildebrandt, S., Sánchez, J.J., Afonso, J.M., 2008. Development of two new microsatellite multiplex PCRs for three sparid species: Gilthead seabream ( Sparus auratus L.), red porgy ( Pagrus pagrus L.) and redbanded seabream ( P. auriga, Valenciennes, 1843) and their application to paternity studies. Aquaculture 285, 30–37.] and 100% success was obtained. Seventeen dams and 11 sires contributed to the spawn and a total of 89 full-sib families (eight paternal half-sib families and 16 maternal half-sib families) were represented. The heritability estimates at harvest were 0.34 ± 0.06 for body weight, 0.33 ± 0.07 for fork length, 0.13 ± 0.04 for condition factor, 0.26 ± 0.06 for gutted body weight, 0.15 ± 0.04 for fillet weight, 0.31 ± 0.07 for dressing percentage, and 0.12 ± 0.03 for fillet percentage. For growth traits at different ages, heritabilities ranged from 0.28 to 0.34 for weight, from 0.27 to 0.35 for length, and from 0.05 to 0.13 for condition factor. At any age, the correlation between weight and length was close to one. Correlations for lengths or weights at two consecutive ages were also high but they decreased with increasing difference in age. Negative and medium genetic correlations between fillet percentage and growth traits (weight and length) were obtained, however these correlations were positive and high for fillet weight. These data suggest that direct selection of length, which is an easily measurable trait, also improves carcass traits. However, the inclusion of fillet percentage in breeding programmes is recommended due to the negative genetic correlation with length. These results highlight the potential for the gilthead seabream industry to improve its production not only through handling but also through the exploitation of additive genetic variation.