GMT Nile Tilapia Orechromis niloticus Growth and Lipid Composition Fed a Spirulina Commercial Pellet Combination or Commercial Pellet Only

Nile tilapia Oreochromis niloticus are capable of digesting cyanobacteria and algae material with low stomach pH. Combining algae with commercial pellets would replace fish meal and more expensive ingredients as well as provide additional nutrients. Algae production and utilization is a key component of integrated polyculture systems. To further evaluate the replacement of commercial pelleted feed with algae, an experiment was conducted in indoor tanks with GMT/YY-supermale Nile tilapia fed commercial fish pellets and commercial fish pellets combined with 50% by weight dry Spirulina. Growth was rapid and no significant differences were found. Spirulina-fed fish contained significantly (P 0.01) greater linolenic, docosapentaenoic, eicosatrienoic, and eicosatetraenoic (arachidonic) fatty acids. Total polyunsaturated fatty acids (PUFA) did not differ, however highly unsaturated fatty acids (HUFA) levels were approximately 50% higher and approached significance. Thus, algae replacement of at least 50% by weight provides nutrition for GMT Nile tilapia equal to 100% commercial pellets. As algae is often a byproduct of fed, intensive aquaculture and economically stimulated in fertilized extensive aquaculture, greater utilization of algae by tilapias reduces cost with a resulting better product.