Genetic evaluation of nutritional traits in Malabar red snapper (Lutjanus malabaricus): Heritability and genetic correlations of fatty acid composition

The demand for nutritious seafood highlights aquaculture's role in global food security, with selective breeding now commonplace in many species as an approach to increase productivity and quality of farmed species. The Malabar red snapper (Lutjanus malabaricus) is a high-value marine species where there is interest in selective breeding to improve commercial traits. In this study genetic parameters associated with fatty acid composition were investigated in Malabar red snapper muscle fillet to understand if these traits would respond to genomic selection. The fatty acid profiles of 540 fish from a commercial farm in Singapore were analysed focusing on key components such as omega-3 and omega-6 fatty acids. A genomic relationship matrix, generated using 39,780 high-quality SNPs from a custom 70 K SNPs red snapper array, was employed in a linear mixed model to reveal heritable components of 15 fatty acid-related traits. Heritability for fatty acids ranged from 0.15 to 0.50. Polyunsaturated fatty acids (PUFA), n-3 omega fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) also showed moderate heritability of 0.32 and 0.29, respectively. DHA/EPA (h2 = 0.50) and the sum of EPA and DHA (h2 = 0.46) showed especially moderate-high heritability. High genetic correlations between levels of fatty acids were observed, including alpha-linolenic acid (ALA) with arachidonic acid (ARA; rg = 0.90) and Oleic acid (OA; rg = 0.82). This study demonstrated that variation in fatty acid levels are heritable and thus would respond to selection. The findings highlight the potential to enhance the nutritional quality of Malabar red snapper fillets through selective breeding, contributing to product quality and better health benefits for consumer.