Location: Warmwater Aquaculture Research UnitTitle: Gender nor sex hormones alter the disease susceptibility of channel catfish to Edwardsiella ictaluri Author
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2012
Publication Date: 10/15/2012
Citation: Peterson, B.C., Davis Jr, K.B. 2012. Gender nor sex hormones alter the disease susceptibility of channel catfish to Edwardsiella ictaluri. Journal of the World Aquaculture Society. 43:733-738. Interpretive Summary: Disease susceptibility to exposure to Edwardsiella ictaluri, a pathogenic bacteria to catfish, was determined in channel catfish, Ictalurus punctatus which had been previously fed with estrogen or testosterone in the feed. The comparative susceptibility of male and female catfish was also determined on all male and all female groups of fish. All male fish were produced by mating a YY male catfish with an XX female. The females were produced by hormonal feminization of the all male fry. Only the highest dose of estrogen increased the disease susceptibility below that of controls or testosterone fed fish. Males and females were not significantly different in susceptibility to E. ictaluri.
Technical Abstract: The use of monosex populations for aquaculture is becoming widely used for several species. Monosex populations are not in wide use in the catfish industry but techniques to develop all male populations have been developed. These studies were conducted to determine if there were any differences between male and female channel catfish, Ictalurus punctatus, in disease susceptibility to Edwardsiella ictaluri, one of the most important pathogenic bacteria in catfish culture. Disease challenge experiments were done on fingerling channel catfish fed 17ß-estradiol or testosterone before the challenge, and on all male and on sibling all female fingerlings. The all male populations were produced by mating YY males with normal XX females. Sibling females were produced by hormonally sex-reversing a sub-population of six of the all male families. Weight gain or specific growth rate did not differ in fish fed testosterone or estrogen. Fish fed the highest dose of estrogen (50 mg/kg) had a significant higher mortality (P < 0.05), while mortality was similar in catfish fed 10 and 50 mg/kg of testosterone compared, to controls. There were no differences in mortality between sibling males and females. These data indicate no increased disease susceptibility to E. ictaluri between males and females or due to exogenous sex hormones. Production of all male catfish for culture can proceed without concern for disease susceptibility to E. ictaluri.