Application of surface disinfectants and antibiotics to hybrid Devils Hole pupfish eggs

Authors: Olin G. Feuerbacher, Scott A. Bonar, Paul J. Barrett

Year: 2010 (xlii)

Abstract

Control of vertical transmission of pathogens is of critical importance in hatchery and laboratory settings. In addition to proper animal husbandry, various chemicals have been employed in this endeavor. Surface disinfection of eggs using formaldehyde, iodophors, hydrogen peroxide, and other chemicals has become routine in many hatcheries to control fungal, protozoan, and bacterial pathogens. Similarly, antibiotics are in commonly used for the treatment of specific disease, or as a prophylactic measure in many hatchery situations, though this latter practice is often discouraged. The effects of surface disinfection of eggs, and the effects of antibiotic application either alone or in conjunction with disinfectants were explored with regard to egg hatch rate, larval and juvenile survival, and overall bacterial load in hybrid Devils Hole pupfish, Cyprinodon diabolis x C. nevadensis. We found that both formalin and iodophor disinfection of pupfish eggs led to better survival of larvae, albeit with slightly reduced hatch rates in the iodine treated eggs. Broad-spectrum antibiotics, particularly trimethoprim sulfamethoxazole and chloramphenicol were especially effective in increasing both hatch rate and juvenile survival. Combinations of formalin plus antibiotic further increased survival, while iodophor disinfection plus antibiotic treatment significantly decreased fifteen-day survival of larvae compared to untreated controls.