title: Echium oil increased the expression of a Δ4 Fads2 fatty acyl desaturase and the deposition of n-3 long-chain polyunsaturated fatty acid in comparison with linseed oil in striped snakehead (Channa striata) muscle.
abstract: Despite the potential of vegetable oils as aquafeed ingredients, a major drawback associated with their utilization is the inferior level of beneficial n-3 long-chain polyunsaturated fatty acids (LC-PUFA). Echium oil (EO), which is rich in stearidonic acid (SDA, 18:4n-3), could potentially improve the deposition of n-3 LC-PUFA as the biosynthesis of LC-PUFA is enhanced through bypassing the rate-limiting ∆6 desaturation step. We report for the first time an attempt to investigate whether the presence of a desaturase (Fads2) capable of ∆4 desaturation activities and an elongase (Elovl5) will leverage the provision of dietary SDA to produce a higher rate of LC-PUFA bioconversion. Experimental diets were designed containing fish oil (FO), EO or linseed oil (LO) (100FO, 100EO, 100LO), and diets which comprised equal mixtures of the designated oils (50EOFO and 50EOLO) were evaluated in a 12-week feeding trial involving striped snakeheads (Channa striata). There was no significant difference in growth and feed conversion efficiency. The hepatic fatty acid composition and higher expression of fads2 and elovl5 genes in fish fed EO-based diets indicate the utilization of dietary SDA for LC-PUFA biosynthesis. Collectively, this resulted in a higher deposition of muscle eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) compared to LO-based diets. Dietary EO improved the ratio of n-3 LC-PUFA to n-6 LC-PUFA in fish muscle, which is desirable for human populations with excessive consumption of n-6 PUFA. This study validates the contribution of SDA in improving the content of n-3 LC-PUFA and the ratio of EPA to arachidonic acid (ARA, 20:4n-6) in a freshwater carnivorous species.
authors: Centre for Marine and Coastal Studies, Universiti Sains Malaysia, 11800, Minden, Penang, Malaysia.
authors: Annette
authors: A
authors: Jaya-Ram
authors: Centre for Marine and Coastal Studies, Universiti Sains Malaysia, 11800, Minden, Penang, Malaysia. alex@usm.my.|School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Penang, Malaysia. alex@usm.my.
authors: Alexander Chong
authors: AC
authors: Shu-Chien
authors: School of Biological Sciences, Universiti Sains Malaysia, 11800, Minden, Penang, Malaysia.
authors: Meng-Kiat
authors: MK
authors: Kuah
mesh_terms: D000123:Acetyltransferases / Q000235:genetics; D000818:Animals; D001921:Brain / Q000378:metabolism; D036661:Echium; D044943:Fatty Acid Desaturases / Q000235:genetics*; D000081031:Fatty Acid Elongases; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D029941:Fish Proteins / Q000235:genetics; D019597:Flax; D005786:Gene Expression Regulation / Q000187:drug effects; D008099:Liver / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D010473:Perciformes / Q000235:genetics / Q000378:metabolism*; D010938:Plant Oils / Q000494:pharmacology*
chemical_list: C000630954:ELOVL5 protein, human; D015525:Fatty Acids, Omega-3; D029941:Fish Proteins; D010938:Plant Oils; D044943:Fatty Acid Desaturases; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases
keywords: Channa striata; Echium oil; LC-PUFA; Nutritional regulation; Stearidonic acid; ∆4 Desaturase