Applying cryopreservation to anuran conservation biology

Abstract

Abstract Novel conservation methods have become increasingly important in protecting our remaining biodiversity in the face of unprecedented rates of species declines. One method of maintaining genetic and species diversity is through germplasm cryopreservation. However, our knowledge of cryopreservation relies heavily on studies in domestic or aquaculture species. Moreover, most studies are narrowly focused on a single species. Consequently, the broader application of these methods to wildlife conservation is often unknown or assumed. Here, we examine the response of four anuran species from two families (Anaxyrus fowleri, Anaxyrus baxteri, Lithobates pipiens, and Lithobates sevosus) to three sperm cryopreservation treatments (5, 10, and 15% N,N‐dimethylformamide with 10% trehalose). Within each family, we selected a congeneric species pair with one common, nonthreatened species and one endangered species. We found that endangered species had significantly lower initial sperm quality, though recovery rate of sperm after cryopreservation was not significantly different between nonthreatened and endangered species. Overall, responses to the three treatments were consistent across species, with 5% DMFA with 10% trehalose producing the highest recovery rates in all four species. In addition, cryopreserved sperm were used to successfully produce hatchlings in both of the nonthreatened species. Our results demonstrate that standardized methods developed for anurans can be applied more widely across families and can be transferred from model species to species of conservation concern. These findings form a basis for further exploration into cryopreservation as an effective tool for wildlife conservation in amphibians.

Keywords

• amphibian
• assisted reproductive technology
• Bufonidae
• cryobiology
• Ranidae
• sperm motility