Rainbow trout (O.mykiss) as one of the most farming fish in most of breeding and farming centers of cold water fish, is well-known throughout the world. Rainbow trout feed on feeding diets which are based on several marine fish meal. Regarding the fact that fish meal is the main source of protein in fish food (Morales et al., 1994), as well as the meal is palatable with high nutritional value in commercial foods of Salmonidae, it constitutes 25-65% of the fish diets (Takeshi, 1992).