Title

Development of a Sperm Cryopreservation Protocol for Redside Dace: Implications for Genome Resource Banking

Document Type

Article

Publication Date

2013

Publication Title

Transactions of the American Fisheries Society

Volume

142

Issue

3

First Page

671

Last Page

680

DOI

10.1080/00028487.2012.756433

Abstract

Populations of Redside Dace Clinostomus elongatus have declined in many areas across the species' North American range. Therefore, the development of sperm cryopreservation technology would provide an invaluable means of preserving genetic diversity in populations that are in imminent danger of extirpation. We developed cryopreservation protocols by testing the effects of diluent (buffered sperm motility-inhibiting saline solution [BSMIS]; BSMIS+ glycine; sucrose; and Hanks' balanced salt solution [HBSS]), cryoprotectant (dimethyl sulfoxide [DMSO]; propylene glycol [PG]; N,N-dimethylacetamide [DMA]; and methanol), freezing rate (1, 5, and 10 degrees C/min), and male-to-male variation on sperm quality. Incubating sperm in extenders affected motility; BSMIS+ glycine + methanol, BSMIS+ glycine + PG, and HBSS + methanol were the only treatments for which motility was not significantly different from that of fresh sperm. Sperm frozen with sucrose had higher motility than sperm frozen with BSMIS + glycine, and sperm frozen with DMSO had higher motility than sperm frozen with methanol. Freezing rates were evaluated for BSMIS + glycine, HBSS, and sucrose; all diluents were frozen with DMSO. The effect of freezing rate was not significant for BSMIS + glycine or for HBSS, but an effect was detected for sucrose, with sperm frozen at 5 degrees C/min or 10 degrees C/min having higher motility than sperm frozen at 1 degrees C/min. The effect of extender was not significant at 1 degrees C/min or 5 degrees C/min, but an effect was detected at 10 degrees C/min such that sperm frozen with sucrose had the highest motility. Male-to-male variability was evaluated by using sucrose + DMSO and a freezing rate of 10 degrees C/min. For these males, the sperm motility recovery index ranged from 6.67% to 79.27%, and the sperm velocity recovery index ranged from 21.37% to 57.33%. Our findings demonstrate that cryopreservation of Redside Dace sperm in a sucrose + DMSO extender at a freezing rate of 10 degrees C/min is adequate for preserving genetic diversity via sperm banks. Received August 27, 2012; accepted December 1, 2012