From the Semen Collection Method to the Hatchlings: The Use of Cryopreserved Sperm from Pheasants Fed an Antioxidant-Enriched Diet.

Abstract

Simple SummaryAlthough cryopreservation techniques for use in bird species have advanced greatly over recent decades, especially in relation to domestic species, major gaps in our knowledge and technical capacities remain due to the complexity of the process and the unique particularities of sperm from different species. The hatchability of chicks is the decisive parameter that demonstrates the quality of a frozen–thawed sperm. Since very little information has been published about the common pheasant, a total of six artificial inseminations (AIs) were performed at 3–4-day intervals with doses of 35 × 106 of normal live thawed sperm on a total of 40 females. The inseminated sperm were collected from pheasants fed either a basal diet or an antioxidant-enriched diet and were then processed using a pellet freezing–thawing method, in which dimethylacetamide was used as a cryoprotectant. Regardless of the male birds’ dietary group, the resulting fertility rate from frozen–thawed sperm was approx. 30%, with 8–9 chicks hatching for every 100 eggs incubated.A widely used approach to preserving genetic diversity in birds involves the cryopreservation of semen. In this process, cells are subjected to physical and chemical stresses, but not all cell species respond equally. Many studies have been published on the freezing–thawing of sperm cells from a wide variety of domestic and wild species, on issues ranging from the sperm quality to different protocols, fertilisation success rates, etc. Nevertheless, very little information is available on the common pheasant. To fill this gap, the aim of this study was to describe the pheasant semen collection method, evaluate some qualitative parameters of sperm from males fed an antioxidant-enriched diet, and to test the in vivo fertilising capacity of the cryo-preserved semen. The freezing protocol employed involved pellets thawed by the hotplate method. Dimethylacetamide was used as a cryoprotectant at a final concentration of 6%. A total of six AIs were performed at 3-4-day intervals on a total of 40 females with doses of 35 × 106 of normal live thawed sperm. Males receiving the enriched diet produce more abundant and concentrated ejaculates. Freeze–thawed sperm lost 85% of their initial mobility, and diet influenced neither sperm mobility nor viability. The enriched diet did improve the number of normal freeze–thawed cells and was associated with a lower sperm fracture incidence. Regardless of the dietary group, frozen–thawed sperm resulted in a fertility rate of 30%, with 8-9 chicks hatching for every 100 eggs incubated.