Evaluation of safflower meal as a protein source in diets of rainbow trout [Oncorhynchus mykiss, Walbaum, 1792)]

The effects of different levels of safflower meal (a residue of the plant oil extraction process) in diets of rainbow trout (Oncorhynchus mykiss) on growth performance, nutrient digestibility and body composition were investigated. Four different diets containing 0% (Control group), 10% (Diet 1), 15% (Diet 2) and 20% (Diet 3) safflower meal were formulated for the fish with a mean weight of 132.70 +/- 0.75g fed for 70days. At the end of the experiment, there were no significant differences among dietary treatments for weight gain, specific growth rate and feed conversion ratio (P>0.05). There were also no differences in the digestibility of crude protein and crude lipid between groups (P>0.05). Supplementation of safflower meal in the diets also had no adverse effects on body composition. The results indicate that safflower meal is a promising feed ingredient and can be used up to a concentration of 20% in the rainbow trout diet with no adverse effects on growth performance, nutrient digestibility or body composition.