Spermatozoa Survival in Egg Yolk-Based and Soybean-Based Extenders at Ambient and Chilling Temperature in Domestic Turkeys (Meleagris gallopavo)

SIMPLE SUMMARY: Hunting pressure and loss of habitat exacerbated by climate change have led to a decline in the number of many galliform species, especially those found in the wild. One such species is the Congo peacock, which has been classified as vulnerable. A domestic galliform species such as the domestic turkey can conceivably be used as a model to research and understand reproduction patterns of related wild and endangered species. The collection, preservation and use of the male gametes for assisted reproductive techniques are key to the successful breeding of such species. This study was aimed at developing a suitable semen extender using two extender formulations (egg yolk-based and soybean-based with or without L-ascorbic acid supplementation) and two storage protocols (ambient temperature and chilled). The results show that both extender formulations preserved turkey semen viability for up to 6 h at ambient temperature and up to 24 h at the chilling temperature. In conclusion, the two extenders were similar with regard to semen quality parameters, and L-ascorbic acid supplementation of the turkey semen extenders improved semen quality during liquid storage. ABSTRACT: Populations of many galliform species have declined mainly due to habitat loss and over-hunting, notably the Congo peacock, which has been classified as a vulnerable species by the International Union for Conservation of Nature (IUCN). The domestic turkey, being a species of least concern, which has been reported to be closely related to peacocks, could serve as a model for the optimization of assisted reproductive technologies for the Congo peacock. This study was aimed at developing a suitable turkey semen extender for artificial insemination in field conditions. Semen was collected using the dorso-abdominal massage technique from seven turkey toms and analyzed. Ejaculates with >70% motility and >80% live spermatozoa were pooled and divided into four aliquots (four treatments). Each of the four treatments was extended in a soybean-based extender or an egg yolk-based extender, with or without L-ascorbic acid. Two liquid preservation protocols (ambient temperature (35 °C) and chilled (4 °C)) were employed, and quality parameters including motility, viability and morphology were evaluated. The results show that the two extenders were similar with regard to semen quality parameters, and L-ascorbic acid supplementation of the turkey semen extenders improved semen quality during liquid storage.