Improvements in Channel Catfish Growth after Two Generations of Selection and Comparison of Performance Traits among Channel Catfish, Blue Catfish, and Hybrid Catfish Fingerlings in an Aquarium Rack System

摘要

A 9-week growth study was conducted to compare the fingerling performance of two genetic groups of channel catfish Ictalurus punctatus (United States Department of Agriculture [USDA] 103 and USDA303) with that of blue catfish I. furcatus and their hybrid in an aquarium rack system. Fish of approximately 20 g were randomly selected from multifamily populations and acclimated to the aquarium rack system for 2 weeks prior to the start of the 9-week study. Differences in growth indices, feed and protein efficiency, nitrogen retention, whole-body proximate composition, and plasma cortisol levels were determined at the completion of the study. The USDA303 channel catfish gained significantly more weight and consumed more feed than each of the other genetic groups. Feed and protein efficiency were similar among USDA103, USDA303, and hybrid catfish but were lower for blue catfish. Nitrogen retention was highest for hybrid catfish and lowest for blue catfish. No differences in final body composition were observed between genetic groups when final weight was used as a covariate. Plasma cortisol levels after 9 weeks ranged from 9.7 ng/mL in blue catfish to 24.5 ng/mL in USDA103 channel catfish but were not significantly different among genetic groups. This study demonstrates improved growth of the USDA303 channel catfish after two generations of selection for increased body weight and reports significant differences in performance among channel catfish, blue catfish, and hybrid catfish in an aquarium rack system.