Miller Matthew R, Bridle Andrew R, Nichols Peter D, Carter Chris G
National Centre for Marine Conservation and Resource Sustainability, University of Tasmania, Launceston, Tasmania 7250, Australia.
J Nutr. 2008 Nov;138(11):2179-85. doi: 10.3945/jn.108.091702.
Atlantic salmon (Salmo salar L.) can produce (n-3) long-chain (LC)-PUFA when fed biosynthetic precursors. This has potential for developing sustainable aquafeeds. Echium oil (EO) is rich in stearidonic acid [SDA; 18:4(n-3)] and bypasses the initial Delta6 desaturase (FAD6) step in the (n-3) LC-PUFA biosynthetic pathway. EO was fed to seawater Atlantic salmon for 12 wk and compared with fish fed a diet containing canola oil (CO), a source of alpha-linolenic acid [ALA; 18:3(n-3)] or fish oil (FO) that provides (n-3) LC-PUFA. Fatty acid (FA) composition of liver, white muscle, and whole fish was measured to show whether dietary precursors were endogenously biosynthesized to LC-PUFA. Gene expression of liver FA elongase and FAD5 was upregulated in EO fish compared with FO fish. Furthermore, dietary precursors affected the FA concentrations of direct biosynthetic products in all tissues. The increased gene expression in the EO fish was reflected by an increased FA concentration of eicosapentaenoic acid [20:5(n-3)] in the liver compared with the CO fish. However, the high concentrations of (n-3) LC-PUFA found in seawater Atlantic salmon fed diets rich in FO were not attained via biosynthesis from precursors (ALA or SDA) in diets.
大西洋鲑鱼（Salmo salar L.）在投喂生物合成前体时能够产生（n-3）长链（LC）-多不饱和脂肪酸。这为开发可持续水产饲料提供了潜力。紫花油（EO）富含硬脂酸（SDA；18:4（n-3）），并绕过了（n-3）LC-多不饱和脂肪酸生物合成途径中的初始Δ6去饱和酶（FAD6）步骤。将EO投喂给海水养殖的大西洋鲑鱼12周，并与投喂含有菜籽油（CO）（α-亚麻酸[ALA；18:3（n-3）]的来源）或提供（n-3）LC-多不饱和脂肪酸的鱼油（FO）的饲料的鱼进行比较。测量肝脏、白色肌肉和全鱼的脂肪酸（FA）组成，以显示膳食前体是否内源性生物合成到LC-多不饱和脂肪酸中。与FO鱼相比，EO鱼肝脏中FA延长酶和FAD5基因的表达上调。此外，膳食前体影响了所有组织中直接生物合成产物的FA浓度。与CO鱼相比，EO鱼肝脏中二十碳五烯酸[20:5（n-3）]的FA浓度增加，反映了EO鱼基因表达的增加。然而，投喂富含FO饲料的海水大西洋鲑鱼中发现的高浓度（n-3）LC-多不饱和脂肪酸并非通过饲料中前体（ALA或SDA）的生物合成获得。
