A PROCEDURE FOR POITOU JACKASS SPERM CRYOPRESERVATION

We have tried to establish sperm banking for the endangered Poitou don keys. No successful cryopreservation technique had been described for spermatozoa of this species; our preliminary work indicated that a par ticular medium and procedure may be effective for cryopreservation of Poitou jackass spermatozoa as evaluted by sperm motility, membrane int egrity and pregnancy rate after AI with frozen-thawed semen. We found that glutamine at 80 mM and 10% (v/v) quail egg yolk in a basal medium containing 4% (v/v) glycerol (T2-94 medium) improved the post-thaw to tal and progressive motility and velocity assessed with the automated analyzer ATS-M. The T2-94 medium also preserved the sperm nuclear, acr osom, and plasma membrane integrity as assessed with the acridine oran ge method, fluorescein-conjugated Pisum sativum agglutinin (FITC-PSA) lectin procedure, and hypo-osmotic swelling test, respectively. Semen frozen-thawed in T2-94 medium as used to artificially inseminate. 13 P oitou jennies from the beginning of estrus to ovulation during 4 cycle s at a rate of one AI per day. Heigh pregnancies and 3 foals were obta ined, but only when the glycerol was removed from sperm before AI. We conclude that the cryopreservation of Poitou jackass semen for sperm b anking may succeed by using the T2-94 medium and removing the glycerol post-thaw, but before AI. (C) 1998 by Elsevier Science Inc.