Impact of sperm concentration on sperm morphology of large white and landrace boars

Abstract

The aim of the study was to determine the dependence of semen quality, frequency of sperm defects, and sperm dimensions and shape on sperm concentration in ejaculates of Large White and Landrace boars. A total of 648 ejaculates collected from 31 Large White and 30 Landrace boars were divided into three groups according to the criterion of sperm concentration. The physical characteristics of all ejaculates were determined, and morphological and morphometric examination of spermatozoa was performed. The characteristics of the ejaculates, frequency of sperm defects, and dimensions and shape of spermatozoa were shown to depend on the sperm concentration. Ejaculates with a high sperm concentration contain a large number of sperm, but have a smaller volume than ejaculates with a lower sperm concentration. Sperm from ejaculates with the lowest sperm concentration have larger dimensions than sperm from ejaculates with intermediate and high sperm concentrations. This is expressed in a larger head area and perimeter and in greater total sperm length. The dependence of the ejaculate characteristics and the size and shape of sperm on the sperm concentration is influenced by the breed. In the ejaculates of Landrace boars, these relationships are more pronounced than in Large White boars. An increased sperm concentration reduces the occurrence of the Dag defect but promotes the occurrence of sperm with a proximal droplet, a pseudodroplet, or a distal droplet.