n-3 PUFA Fortification of High n-6 PUFA Farmed Tilapia with Linseed Could Significantly Increase Dietary Contribution and Support Nutritional Expectations of Fish

Farmed fish high in n-6 PUFA may undermine fish nutritional expectations and intake recommendations for n-3 PUFA requirements and exacerbate rather than improve already high n-6/n-3 PUFA diets. Dietary contribution of fish fortification by linseed-based n-3 PUFA was evaluated. Mango tilapia (12 months old) with high n-6 PUFA (21.8 FA%, n-6/n-3 ratio 4.6:1) were fed standard/control (T-c) or linseed-supplemented (5%, T-5%; 7%, T-7%) feed for 61 days regular-growth and 120 days stock-growth (to 650 g). Compared to Tc, n-3 PUFA increased in T-5% 46% and T-7% 58%; ALA in T-5% increased 100% and T-7% 167%; EPA+DHA in T-5% increased 14% and T-7% 23% (p < 0.05); n-6 PUFA/LCPUFA were unchanged. T-7% EPA+DHA 168 mg/100 g of raw fillet is comparable to current American intake and Dietary Reference Intakes; controlled cooking preserved approximate to 90% EPA+DHA. n-6/n-3 ratios decreased 16-38% in total PUFA to 2.3:1 and in LCPUFA to 0.61:1. Linseed supplementation could improve tilapia n-3 PUFA/LCPUFA, ameliorating n-3 PUFA scarcity and unexpectedly high fish n-6 PUFA content, potentially making a significant nutritional contribution.