Effects of Winter Feeding on Growth, Body Composition, and Processing Traits of Co‐Cultured Blue Catfish, Channel Catfish, and Channel Catfish×Blue Catfish Hybrids

Abstract

AbstractThe effects of winter feeding on growth, body composition, and processing yield were compared for co‐cultured blue catfish Ictalurus furcatus, channel catfish I. punctatus, and channel catfish×blue catfish hybrids. Fish (∼0.4–0.7 kg) from each genetic group were stocked communally at 5,625 fish/ha in ten 0.04‐ha ponds during mid‐November. Fish in five ponds were fed at 2% of initial body weight twice per week; fish in the other five ponds were not fed. The study was terminated after 14 weeks, and fish were weighed and processed. Analyzed traits were weight change (%), survival, and yields (%) of carcass, shank fillet, nugget, head, viscera, skin, intraperitoneal fat, liver, and ovary. Among fed fish, hybrids gained the most weight, channel catfish had intermediate weight gain, and blue catfish gained the least weight. Unfed blue catfish lost more weight than unfed channel catfish and hybrids. Survival was not different among genetic groups or between feeding regimes. Interactions among main effects for processing and body composition traits made generalizations difficult, but carcass yield was consistently higher for blue catfish and hybrids than for channel catfish, higher for females than for males, and higher for fed fish than for unfed fish. Shank fillet yield was higher for hybrids than for blue catfish and channel catfish, higher for females than for males, and higher for fed fish than for unfed fish. Nugget yield was higher for blue catfish than for channel catfish and hybrids and was higher for fed fish than for unfed fish. Blue catfish and hybrids had higher intraperitoneal fat yield and lower liver and ovary yield than channel catfish. Fed fish had higher intraperitoneal fat and liver yield than unfed fish. Winter feeding improved growth and fillet yield in all groups, but the benefits of winter feeding were lower for blue catfish than for channel catfish and hybrid catfish.