Effects of different levels of canola meal on growth, body composition and biochemical parameters in Rainbow Trout (Oncorhynchus mykiss)

Rainbow trout with initial body weight 4.16 plus or minus 0.25 g were fed diets that contained crude protein 42%; gross energy 4400 Kcal/kg DM; crude fat 10% including graded levels of canola meal (CP 35% DM). A growth trial was conducted over 16 weeks at a water temperature of 12 plus or minus 1C. At the end of the growth trial, in addition to body composition analyses, plasma triiodothyronine (T3) and thyroxin (T4), cholesterol and liver fatty acid composition were measured. Replacement of fish meal with canola meal (10 to 57% replacement) did not significantly affect the growth performance (P>0.05). At 16th week, plasma cholesterol levels were reduced in fish fed with all diets in comparison to 8th week. Plasma T4 levels were significantly higher in the canola meal-fed fish sampled after 16 weeks, but no significant differences in T3 levels were obtained (P>0.05). Proximate composition was affected by dietary treatments. The liver fatty acid composition reflected that of the fish fe.....