Delivering a Nutritionally Enhanced Tilapia Fillet Using a Pre-Harvest Phase Omega-3 Thraustochytrids Protist Enriched Diet

Nile tilapia (Oreochromis niloticus) offers an affordable food source to many low-income consumers. However, farmed tilapia has drawn much criticism over the low omega-3 (n-3) and high omega-6 (n-6) lipid levels. Subsequently, it has been questioned whether it is truly healthy food. This study fed tilapia with a specialized “finishing” diet with the inclusion of commercial Thraustochytrids protist biomass and oil before the harvestable fish size. The fish are fed with two different dietary regimes over 6 weeks. One is a commercially available tilapia feed used as a reference. The second diet is composed of an exclusive oil source from Thraustochytrids protist (HI-n3). The results show that HI- n3 has significantly increased the fillet n-3 content by 400% in comparison to commercial diet (COM) after Week 6 of feeding. Specifically, docosahexaenoic acid (DHA, n-3) content is the attributing fatty acid for the n-3 increase. This is particularly evident when DHA is expressed as a percentage of total lipid content. The n-3:n-6 ratio increased in tilapia fed with the HI-n3 diet attributed to the DHA accumulation. The investigation shows that it is possible to favorably “lipid tailor” tilapia before harvest. Practical applications: The practical application of this technique is to enrich farmed tilapia with a high dietary omega-3 (n-3) Thraustochytrids protist oil source for a short-term period before harvesting. It is an objective that the fillet product would be more functional in its nutritional content by supplying more than just high-quality protein for consumers. This would have paramount implications for low-income consumers, where high n-3 oil foods are not readily available or affordable (e.g., landlocked nations). Furthermore, tilapia is widely consumed in China and Southeast Asian countries but is also promoted as a high nutritional value food source in the western hemisphere. This investigation advocates the ability to change the image of this fish species by a simple dietary manipulation. In an era of elevated intake of omega 6 (n-6) fatty acids food sources, n-3 rich fish is a vital balance to counter this negative trend in human health.