In Vitro Gene Conservation Status and the Quality of the Genetic Resources of Native Hungarian Sheep Breeds

Abstract

Studies revealed a global loss of genetic resources for local sheep breeds. Therefore, the current study aimed to introduce and highlight the progress made on Hungary’s existing gene conservation program (small Gene Bank). Furthermore, we evaluated breed (Tsigai, Cikta, and Racka), season, and individual variabilities (n = 24) of the pre-freeze and post-thaw semen stored in the Gene Bank to enhance the gene conservation of the breeds. The samples were cryopreserved manually, and post-thaw spermatozoa were analyzed for motility (CASA), viability, chromatin structure, and morphometry of the sperm nuclei. Ejaculate volume, spermatozoa concentration, subjective motility and standard motility, kinematic parameters, and spermatozoa’s head area standard deviation of the post-thaw samples differed significantly among breeds (p < 0.05). Season affected ejaculate volume, total spermatozoa number/ejaculate, STR, BCF, and ALH. We observed a significant (p < 0.001; 0.05) breed and season interaction on concentration, total spermatozoa number/ejaculate, VCL, LIN, WOB, spermatozoa’s head average perimeter and nucleus length (Tsigai and Cikta differed but were statistically the same as Racka). Similarly, season significantly (p < 0.05) affected the proportion of ejaculate suitable for freezing. There was a significant (p < 0.05) difference in kinematic parameters and viability among the rams across the breeds. The spermatozoa’s head morphometry of the Tsigai and Cikta breeds differed significantly (p < 0.05) among the rams. There were individual and breed differences in many spermatozoa quality parameters. The stored samples are of good quality, with more than 40% having intact membranes and low abnormal chromatin condensation.