The effect of sperm concentration on the morphometric traits of spermatozoa of the Arctic fox ( Vulpes lagopus )

Abstract. The ability of spermatozoa to penetrate the egg and their competitiveness in the female reproductive organs may depend on their dimensions and shape, and these are often related to the characteristics of the ejaculate. This study aimed to assess the degree of dependence of the morphological features of spermatozoa on sperm concentration in the ejaculate of the Arctic fox (Vulpes lagopus). The research material consisted of ejaculates collected once by manual stimulation from 20 1-year-old foxes. All ejaculates were analysed for standard parameters (volume, sperm concentration, total number of spermatozoa in the ejaculate). Morphometric measurements of spermatozoa were also performed, on the basis of which spermatozoa shape indexes were calculated. It has been shown that the concentration of sperm in the ejaculate affects the morphological characteristics of male Arctic fox sperm. A high concentration of sperm favours the development of minor morphological changes. As the concentration of sperm in the ejaculate increases, the percentage of spermatozoa with major morphological changes decreases. The most common morphological anomaly of sperm in the ejaculates is the “Dag-like” defect, which is most common in ejaculates with the lowest sperm concentration. It has also been shown that, as sperm concentration increases, the dimensions of spermatozoa heads and tails decrease. Sperm concentration affects the shape of Arctic fox sperm. As sperm concentration in ejaculate increases, the ellipticity and elongation indicators decrease, while the head length / total spermatozoa length indicator gradually increases.