Spatial distribution of fatty acid composition in salmon fillets

Fatty acid analysis is crucial in assessing the nutritional value of salmon fillets, particularly the content of long-chain polyunsaturated fatty acids. The first detailed study of spatial distribution of fatty acid composition in salmon fillets is presented. Fish were collected at mid-grow and commercial harvesting stages from two locations, and were fed with three different feeds with varying ratio of vegetable and marine oil. Sampling within fillets was conducted at six positions along the anteroposterior, dorsoventral, and radial axes. Lipid analysis was performed using gas chromatography. The results show that feed had the biggest influence on fatty acid profiles, followed by sampling position, while growth stage had minimal influence. Substantial differences in fatty acid compositions were observed along both the dorsoventral and anteroposterior axes of the fillets. The Norwegian Quality Cut (NQC) area closely reflects the median fillet composition, making it a reliable reference region. Fillet areas with low lipid content, particularly the tail section, have the highest DHA and EPA content. A strong correlation was found between aggregate DHA and EPA content in the untrimmed belly fat region and the NQC area, suggesting that this region could serve as a convenient measurement area for assessing salmon fillet nutritional value. • Fatty acid composition varies significantly across all three axes of salmon fillets • Fish feed has the most substantial impact on the lipid fatty acid profiles. • Fillet areas with low lipid content have the highest content of DHA and EPA. • Belly fat region could be ideal for assessing lipid nutritional value of fillets.