2009/779 Yellowtail Kingfish growth response, flesh quality and PUFA content through microalgae formulated aqua-feeds

By Kopano Mosa Machailo

Yellowtail Kingfish (YTK) is an emerging aquaculture species, and there is an increase in the demand for the fish, both for recreational fishing and for export purposes. Many fish, including YTK have a requirement for microalgae in their diet; however there is currently very limited supply of microalgae in Australia for use in commercial applications. Development is underway to encourage growth of the microalgae industry with a specific focus on developing a biorefinery system. One of the main aspects of the biorefinery system will be to use waste generated by the production of biofuels in other industries which will provide value addition to the waste products from the production of biodiesel. One of the expected waste products of lipid extraction from the production of biofuels are be microalgae proteins and this study investigated whether these proteins may be used in the aquaculture industry.

In this study, we aimed to use cultured/commercially available microalgae biomass as an alternative protein source for Yellowtail Kingfish. We also examined the palatability of microalgae in fish feed and observed changes in growth, performance and fillet quality of the Yellowtail Kingfish. Three diet formulations were devised for this study: a control diet made by Ridleys™ and two treatment diets which replaced some of the fish meal with the microalgae, spirulina, resulting in diets that contained 20% Spirulina and 30% Spirulina. Feed trials were conducted for eight weeks, followed by biomass growth analysis and biochemical properties of the fillets obtained from the fish that were provided the dietary formulations.

The results of this study indicate that the performance of the microalgae formulated feed is comparable to the control diet. This study has provided an opportunity to further explore the use of microalgae in fish feed particularly yellowtail kingfish and this has the potential provide low cost protein source alternatives for use in aquafeeds.

For more information on Seafood CRC students and where they are now, please click here.