In aquaculture, feed costs contribute for between 50 and 70 percent of overall production costs. Given the world's rapidly expanding aquaculture production, fish oils (FO) obtained from finite wildcatch fisheries will not be able to supply the rising demand for aquafeeds. To decrease reliance on global capture fisheries, it is essential to seek out sustainable alternatives for FO. Microalgal feed stuffs could become one of the aquaculture industry's most promising and sustainable alternatives. Algal meal 8.77% was determined to be the optimum diet for dramatically changing the lipid profile of tilapia fillets at week eight. In one study, the substitution of fish oil with algal flour and vegetable oil resulted in an increase in the weight and nutritional value (n-3 PUFA and LC-PUFA) of shrimp muscle. The combination of algal meal and vegetable oil might replace 75% of the fish oil in shrimp diets. These data indicate that up to 100 percent of FO can be replaced with S.limacinum meals, hence enhancing the growth of T. macdonaldi while maintaining the nutritional value and health advantages of the fillet. This is the first report of increased feed utilization indices, weight gain, and beneficial fatty acid profiles in Nile tilapia when fish oil is completely substituted by 16% of dried whole-cells of a marine microalga species, Schizochytriumsp (Sc). All of these data demonstrate the viability of using microalgae as a fish feed ingredient in place of fish oil to improve the growth and immunity of fish.

Keywords : Aquaculture, Microalgae, fish oil, growth performance, immunity