Abstract
Withholding feed has been suggested as a strategy to manage infectious disease of channel catfish, Ictalurus punctatus (Rafinesque). In a previous study, we demonstrated that deprivation of feed for as little as 7 days reduced innate resistance of catfish to Flavobacterium columnare . This study was conducted to evaluate the effect of feeding regimens [no feeding (NF), fed once every other day to satiation (FEOD) and fed once daily to satiation (FD)] on organosomatic indices, physiological changes and susceptibility of channel catfish to F. columnare . Fish that were not fed for 2 and 4 weeks had a significant increase ( P −1 ) was significantly lower than that of the FD fish (41.77 mg mL −1 ). Significantly lower ( P −1 ) and liver glycogen (1.7 and 1.8 mg g −1 ) were seen in the NF fish at weeks 2 and 4, respectively, as compared with blood glucose and liver glycogen levels of FD fish (67.5 and 92.8 mg dL −1 and 46.5 and 52.6 mg g −1 at weeks 2 and 4, respectively) and FEOD (82.8 and 85.5 mg dL −1 and 45.1 and 51.4 mg g −1 at weeks 2 and 4, respectively). Mortality in the NF fish caused by F. columnare (78%) was significantly higher ( P −1 and 2 mg g −1 , respectively, are indicative of starvation in juvenile channel catfish. Moreover, NF fish were susceptible to F. columnare infection. Thus, it is suggested that in the absence of natural food, juvenile channel catfish should be fed at least once every other day to apparent satiation to maintain normal physiological function and improve resistance to F. columnare .