The Effects of Different Sized Granules and Particle Composition on Growth of Rainbow Trout (Oncorhynchus mykiss)

Abstract

Three feeding regimes were tested to determine their effects on growth, survival, and feed conversion in rainbow trout alevins for 60 days. In the first regime, the alevins were fed a starter feed consisting of 800 micron parti- cles for the first 15-day period. For the following 15-day period, the alevins were given a starter feed consisting of 1200 micron particles. For the final two 15-day periods, the alevins were given feeds consisting of 1500 micron and 2 mm particles, respectively. In the second regime, feed particles in the four periods were 1200 micron, 1500 micron, 2 mm, and 3 mm granules, respectively. In the third regime, feeds contained 1500 micron, 2 mm, 3 mm, and 4 mm granules. During the first two 15-day periods, no significant dif- ferences in growth parameters were detected (p>0.05). In the second two 15-day periods, there were significant differences in final live weight, growth, and feed conversion rates between groups (p<0.05). Growth was lowest in the group fed the first regime. There were no significant differ- ences between groups in survival rate (p>0.05).