Effect of Dietary Oils on the Accumulation of Conjugated and Other Polyunsaturated Fatty Acids in Zebrafish Tissues

Dietary polyunsaturated fatty acids (PUFA), including conjugated linolenic acids, are increasingly investigated for their potential health benefits. Zebrafish have emerged as a promising in vivo model for studying the metabolism and effects of such bioactive compounds. The present study tested whether zebrafish tissues could be enriched with specific PUFA through dietary modulation. To do so, six-month-old female zebrafish were divided into four groups and fed purified diets over an eight-week period, each diet containing a distinct lipid source: sunflower oil (rich in linoleic acid), linseed oil (rich in alpha-linolenic acid), fish oil (rich in eicosapentaenoic acid and docosahexaenoic acid), and pomegranate seed oil (rich in punicic acid, a conjugated linolenic acid). Body mass, length, and whole-body fatty acid profile were then assessed. An efficient incorporation of linoleic acid, alpha-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, or punicic acid into zebrafish tissues was observed, depending on the dietary source. Linoleic acid and alpha-linolenic acid underwent partial bioconversion into longer and more unsaturated fatty acids. Fish fed with pomegranate seed oil were enriched in conjugated linoleic acids (rumenic acid and 18:2 (trans-9, trans-11)), suggesting the presence of a Δ13 reductase activity in zebrafish. These findings highlight the suitability of zebrafish as an in vivo model for investigating the impacts of specific dietary and metabolically derived PUFA in the context of health and disease.