Application of prophylactic disease treatments in laboratory rearing of hybrid Devils Hole pupfish

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

Year: 2009 (xli)

Abstract

Laboratory cultivation of Devils Hole pupfish, Cyprinodon diabolis, has proved to be problematic for many years. Although various attempts have been made, long term maintenance and cultivation of this species over multiple generations has thus far been unsuccessful under laboratory conditions. Several strategies are being employed to elucidate the mechanisms behind these difficulties, utilizing hybrid Devils Hole pupfish, C. diabolis x C. nevadensis mionectesas as a model. Work is underway to culture these hybrids in biotic and abiotic conditions similar to those found in Devils Hole to determine the reproductive and developmental challenges of living in such harsh conditions. Microbiological and histological analyses are being performed to understand potential pathogens that may affect the physiology of C. diabolis, as well as to design strategies that maximize hatch success. Because many of the bottlenecks previously identified in the captive breeding of Devils Hole pupfish have been during larval rearing, particular effort has been placed on maximizing larval survival. Several prophylactic antimicrobial therapies have been compared as they relate to egg hatch rate, larval survival, and long term clearance of targeted pathogens. Treatments of moderate and broad-spectrum antimicrobials were successful in improving hatch rates and larval survival. Mycobacterium-targeted therapies have demonstrated potential for creating specific-pathogen-free lines. These lines could allow for investigation of the intricacies of larval developmental physiology and functional genomics without the confounding effects of chronic disease burdens.