Stability of muscle fatty acids and proximate composition across phenotypic traits in Malabar red snapper (Lutjanus malabaricus)

This study evaluated the influence of biological and phenotypic traits on the muscle nutritional composition of Malabar red snapper ( Lutjanus malabaricus ). A total of 540 farmed fish were analysed for fatty acids, ash, dry matter, and protein across sex, size, weight, health, and colour groups. Muscle lipids were dominated by saturated fatty acids (36.1%), followed by polyunsaturated (35.0%) and monounsaturated fatty acids (27.5%). Major fatty acids included oleic acid (22.7%), linoleic acid (15.5%), docosahexaenoic acid (11.7%), eicosapentaenoic acid (3.0%), α-linolenic acid (1.1%), and arachidonic acid (0.22%). Across all traits, model explanatory power was low (adjusted R² = 0.01–0.09), and most predictors showed no significant effects. When significant associations were detected, effect sizes were small, typically representing changes of less than one percentage point. Proximate components (ash ∼5.4%, dry matter ∼94%, protein ∼22%) also showed minimal variation across phenotypic groups. These results demonstrate that muscle fatty acid and proximate composition are highly stable across biological and phenotypic traits, providing robust baseline data for food composition assessment and supporting the nutritional consistency of farmed Malabar red snapper.