NUTRITIONAL AND THERAPEUTIC POTENTIAL OF SPIRULINA (Arthrospira) AS AN AQUACULTURE FEED

Diminishing wild harvest of fish used as fish meal, sustainability issues of such practices and significant increase in aquaculture production of fish (which is now equal to the amount of wild catch) has resulted in great demand for aquaculture feed. This has resulted in an increased attention to microalgae as alternative sources of aquaculture feed. Microalgae are a diverse group of organisms that produce a whole series of nutritional components for fish nutrition and health ranging from amino acids, poly-unsaturated fatty acids, vitamins, minerals, antioxidants and antimicrobials.

The filamentous cyanobacterium, Spirulina (Arthrospira) has been grown commercially as food and to some extent as feed for almost 40 years. Several studies conducted in the last few years point to its potential as aquaculture feed especially as a protein supplement. Spirulina has a good balance of essential amino acids in its protein with the exception of sulfur-containing amino acids and can therefore be used to supplement other protein sources. Feeding Spirulina to various fish has also shown good digestibility, food conversion efficiency and growth rates. Moreover, several therapeutic effects ranging from antioxidant/anti-inflammatory effects, immunomodulation and probiotic effects have been established which could benefit fish health. Spirulina is currently used in larval and juvenile fishes to boost their immune system. It strong antioxidant properties will also benefit reduce oxidative stress that fish are constantly subjected to from heavy metals, pesticides, other environmental pollutants and even changes in temperature.

This presentation will review studies on the effect of Spirulina in fish nutrition and health and also discuss some of the current problems of commercial production of algae for aquafeeds.