The Distribution of Boars Spermatozoa in Morphometrically Distinct Subpopulations after In Vitro Exposure to Radiofrequency Electromagnetic Radiation at 2500 MHz and Their Motility.

Anthropogenic radiofrequency electromagnetic radiation (RF-EMR) from wireless technologies has increased dramatically. The boar semen used for artificial insemination is essential in sustaining the pig industry, and additionally it is also exposed to the effects of the RF-EMR of wireless technologies. Furthermore, there are no data on the effects of RF-EMR on semen quality, and this is the first analysis of sperm's morphometric parameters for assessing the effect of RF-EMR on the spermatozoa subpopulations of boars. This study investigated the effect of RF-EMR on in vitro exposed breeding boar semen spermatozoa motility and the proportions of spermatozoa subpopulations according to their morphometric head and tail parameters. The semen samples of 12 boars were divided into control and experimental groups. The samples in the experimental group were exposed in a gigahertz transverse electromagnetic chamber at a frequency of 2500 MHz (the frequency band used in 5G technology) and an electric field strength of 10 Vm-1 for two hours. After exposure, the spermatozoa motility was evaluated for both groups. A morphometric analysis of the semen smears was performed using SFORM software (Version 1.0; VAMS, Zagreb, Croatia). The progressive spermatozoa motility was significantly reduced in the experimental group (74.7% vs. 85.7%). PC analysis and cluster analysis revealed two spermatozoa subpopulations: S1, spermatozoa with a more regular head shape and a smaller midpiece outline, and S2, spermatozoa with a more elongated head shape and a larger midpiece outline. The experimental semen samples had a greater proportion of the S1 spermatozoa subpopulation (68.2% vs. 64.4%). The effect of RF-EMR at 2500 MHz on the in vitro exposed boar semen resulted in decreased progressive spermatozoa motility and a lower proportion of the spermatozoa subpopulation with a higher fertilizing potential.

Exogenous melatonin influences distribution of French Alpine buck spermatozoa in morphometrically distinct subpopulations during the non-breeding season.

The aim of this study was to establish subpopulations of spermatozoa in bucks using the principal component (PC) and cluster analysis according to morphometric head and tail variables, and to determine differences in proportions of subpopulations between exogenous melatonin-treated and control bucks. The bucks (n = 12) were assigned to two groups comprising six bucks each. By the end of March, four melatonin implants were inserted in the bucks in the experimental group. Semen was collected weekly using an artificial vagina from March to May (the non-breeding season). Analyses were performed in stained smears by SFORM computer-assisted program for eight head and five tail variables. The PC analysis revealed four components with the most important value for each (head outline, head ellipticity, mid-piece length and width). Cluster analysis indicated there were three subpopulations (average-sized spermatozoa- C_1; small and less-elliptic - C_2; big and elliptic - C_3). Melatonin-treated bucks had a greater proportion of C_1 spermatozoa and a lesser proportion of C_2 spermatozoa during May (P < 0.05). To the best of our knowledge, this is the first study where PC and cluster analyses were performed on buck semen with head and tail variables analyzed together, in the same analysis, to evaluate spermatozoa population. Also, this is the first analysis of morphometric variables for assessing the influence of melatonin on spermatozoa subpopulations. The positive effect of melatonin on the proportions of spermatozoa in subpopulations could have been a consequence of the decreasing the proportion of the subpopulation with the least head and tail sizes and ellipticity.