Introduction of flaxseed (Linum usitatissimum L.) and an overview on its role in aquatics nutrition

One of the challenges facing the increasing growth of the aquaculture industry in the last decade is paying attention to the production of economical aquafeeds. Fishmeal as a source of protein required by aquatic species faces problems such as price increment, quality fluctuation and the presence of various chemical and microbial contaminants. Therefore, attention to the use of alternative protein sources of fishmeal, including plant protein sources, is considered. Flaxseed is an essential source of crude protein, crude fat and precursor fatty acids. Oil, especially the meal of flaxseed, has a good nutritional value for use in aquatic diets. The presence of some anti-nutritional compounds such as linamarin from the group of cyanogen glycosides in flaxseed has made difficult on the use of this valuable nutrient in the diet of aquatic animals. The use of appropriate processing methods such as expansion and extrusion reduce these compounds.