Effects of Initial Feed Timing on Early Survival and Growth of Triploid Hatchery Rainbow Trout

Abstract

AbstractThe timing of initial feeding for trout fry varies greatly among hatchery professionals and may affect early survival and growth. The purpose of this study was to determine if there is a number of days posthatch to begin feeding triploid hatchery Rainbow Trout Oncorhynchus mykiss where they will experience the least mortality and most favorable growth rates. Treatment groups of triploid Rainbow Trout fry were fed for 30 d with initial feeding times of 13, 15, 17, 19, 21, and 25 d posthatch on 12.2°C water. Variations in survival, condition factor, size, and feed conversions between initial feed times were evaluated. The number of days posthatch prior to initial feeding did not have a significant impact on survival. The growth parameters measured showed significant variation depending on days posthatch prior to initial feeding, with the most favorable growth parameters found at 21 and 25 d posthatch.Received October 29, 2015; accepted February 13, 2016 Published online June 15, 2016