Cryopreservation protocols of guinea fowl sperm

Supporting the rescue of the valuable indigenous domestic animal species is an important part of the new Hungarian agricultural strategy. In the case of poultry species semen cryopreservation is the most practical method for the long term storage of the genetic material. So far, only a single study is available on the freezing of guinea fowl sperm. In the study three freezing protocols were compared: a slow, programmable method with two different cryoprotectants - 10% ethylene glycol (EG), and 6% dimethyl-formamide (DMF) - and vitrification in pellet form, using 6% dimethylacetamide (DMA). During the in vitro sperm qualification the analysis of membrane integrity was made with eosin-aniline staining. The efficiency of the protocols which produced more acceptable sperm survival was controlled by artificial insemination, as well. For fertility determination candling of incubated eggs was used, extended by checking of the ratio of early embryonic mortality. Two freezing protocols (programmable with 10% EG and pellet) resulted in good survival rate of live, intact spermatozoa (23 vs. 29%, respectively), while slow freezing with DMF produced only 11% survival rate. The differences between slow and fast freezing proved to be significant (p <= 0.05). Artificial insemination was made with fresh and two kinds of frozen/thawed semen (slow protocol with 10% EG and vitrification) in three experimental groups. For the 3rd week of insemination fresh sperm resulted 92, slow protocol 29 and pellet method 64% fertility. The proportion of early embryo mortality was remarkably higher in eggs coming from the groups inseminated with frozen thawed sperm. While the rate of fertility increased, the proportion of the early embryonic death decreased as a function of time in all groups.