Microalgae in aquaculture: a review with special references to nutritional value and fish dietetics

Microalgal biotechnology has gained considerable importance in recent decades and its use is extending day by day into several areas like nutraceutical research, renewable energy source, production of essential biomolecules like β-carotene, astaxanthin, PUFA, bio colorant production, wastewater treatment, bioremediation and aquaculture etc. Among all these, microalgae as a source of nutrition have drawn the attention since long back and are widely used in animal nutrition. Fishmeal is the preferred protein ingredient of feed in aquaculture industry, contributing significantly to the variable production cost. However, decreasing fishmeal supply and increasing costs threaten the sustainability and growth of the aquaculture industry. Therefore, complete or partial substitution of fishmeal with alternative proteins is needed to solve the problem. Presently, microalgae are used worldwide as an alternate protein source replacing fishmeal successfully. In feeding trials with fish, many types of microalgae have been found to be used for increasing growth (protein accretion), feed utilization, physiological activity, stress response, starvation tolerance, disease resistance, and carcass quality. In the present communication an attempt has been taken to review the application of different microalgae in rearing of aquaculture animal especially the fishes.