Growth Performance and Mitochondrial Function in Juvenile Rainbow Trout (Oncorhynchus mykiss) Fed Graded Dietary Lipid Levels - Abstract
A 2x3 factorial study was conducted to evaluate the effects of dietary lipid level on growth, feed utilization and mitochondrial enzyme activities in juvenile all-female rainbow trout (Oncorhynchus mykiss). Isonitrogenous diets with 400 g kg-1 crude protein, formulated to contain 100 (diet 40/10), 200 (diet 40/20) and 300 (40/30) g kg-1 dietary lipid, were fed to triplicate groups of high-feed efficient (F136) and low-feed efficient (F120) families with 217.66±2.24 g and 205.47±1.27 g initial average mass, respectively, for 90 days. At the end of the experiment, F120 fish fed diet 40/20 showed highest growth (P<0.05). Feed intake was not affected by the treatments (P>0.05). The genetic background (family effect) did not affect feed utilization (P>0.05). Dietary lipid level beyond 200 g kg-1 decreased feed efficiency and increased fat content in fish (P<0.05). The complex II activity in the liver, complex V activity in the intestine and the activities of complexes II and IV in the muscle were affected by the interaction diet x family; the diet and the genetic variation
simultaneously affected the complex III activity in the muscle (P<0.05). The high feed efficiency is associated with high complex III activity in the intestine and the muscle.
Results also suggest that genotype x diet interactions should be accounted for when considering strategies for using mitochondrial function as a criteria in rainbow trout selection programs for improved growth performance characteristics.