The effects of moderate and high temperatures on growth, metabolism, and blood-oxygen affinity in Ictalurus spp.

Despite the growing use of hybrid catfish (Ictalurus furcatus × I. punctatus) in aquaculture, few studies have investigated the comparative effects of temperature on physiological performance with other cultured catfish. Therefore, growth, metabolism, and blood-oxygen affinity of blue (I. furcatus), channel (I. punctatus), and hybrid catfish were compared at moderate (23°C) and high (33°C) water temperatures. Channel catfish had the greatest growth and were in better condition compared to blue and hybrid catfish. Hybrid catfish standard metabolic rates did not differ from blue or channel catfish, while hybrid catfish had higher maximum metabolic rates, larger metabolic scopes, and better swimming performance than blue and channel catfish. Blue and hybrid catfish had a higher affinity to bind oxygen than channel catfish, with hybrid catfish generally having larger Bohr effects than blue and channel catfish. These results indicate hybrid catfish likely achieve superior performance due to larger metabolic scopes and Bohr effects