Comparison of Production Traits of NWAC103 Channel Catfish, NWAC103 Channel Catfish x Blue Catfish Hybrids, Kansas Select 21 Channel Catfish, and Blue Catfish Grown at Commercial Densities and Exposed to Natural Bacterial Epizootics

摘要

The NWAC103 strain is an improved channel catfish Ictalurus punctatus that has been widely used in the catfish industry. However, it is not yet known whether the hybrid progeny (hereafter termed 103 hybrids) of male blue catfish I. furcatus and NWAC103 females will exhibit further improvement in growth. Therefore, we compared production attributes among four catfish genotypes that were communally reared in earthen ponds: NWAC103, Kansas Select 21 channel catfish, Rio Grande x D&B-strain blue catfish, and 103 hybrids. Compared with the other genotypes, the 103 hybrids had a higher (P < 0.05) growth rate during the food fish stage, better survival when exposed to natural epizootics of enteric septicemia of catfish, and greater production and survival when exposed to critically low levels of dissolved oxygen. Mean weights at the food fish stage were 639.0 g for 103 hybrids, 569.7 g for NWAC103, 514.7 g for Kansas Select 21, and 394.3 g for blue catfish. Production rates were 8,632 kg/ha for 103 hybrids, 5,205 kg/ha for NWAC103, 6,250 kg/ha for Kansas Select 21, and 4,582 kg/ha for blue catfish. Fingerling survival rates were 100% for 103 hybrids, 25.7% for NWAC103, 43.5% for Kansas Select 21, and 72.9% for blue catfish; food fish survival rates were 88.7, 60.0, 82.7, and 76.3%, respectively. The heterosis for body weight was only 12.2%, but the combination of faster growth and greater survival resulted in 65.8% heterosis for production. Channel catfish that have been genetically improved through selection programs can be used to produce channel x blue catfish hybrids with higher performance than the parental species. The improvement via selection does not limit further enhancement via hybridization.