Influence of season and climatic variables on testicular cytology, semen quality and melatonin concentrations in crossbred bucks reared under subtropical climate

Abstract

Seasonality in reproduction and effects of climatic variables on testicular cytology and semen quality in bucks reared under subtropical climatic conditions were not well understood. In the present study, using testicular cytology, semen evaluation and melatonin concentrations assessed over a period of 1 year, we report that bucks reared under subtropical climatic conditions did not show seasonality in reproduction. Climatic variables including temperature, relative humidity, temperature-humidity index (THI), sunshine hours and day length were recorded daily during the whole period of experimentation (one complete year). Ejaculates were collected from crossbred (Alpine X Beetal) males (n = 6) biweekly using artificial vagina, and semen quality (volume, mass activity, sperm concentration, motility, viability, membrane integrity and protamine deficiency) was assessed. To understand the seasonal influence at testicular level, using fine needle aspiration biopsy method, testicular cells were aspirated and different types of cells and testicular cytology indices were quantified. Blood was collected biweekly for estimation of melatonin concentrations. Mass activity was higher (P < 0.05) during rainy season while individual sperm motility and sperm concentration were higher (P < 0.05) during rainy and autumn seasons as compared to other seasons. Sperm functional parameters did not show any differences during different seasons. Sertoli cell count, spermatogenic cell count and testicular indices did not differ among the seasons. Melatonin concentrations also did not differ significantly among the four seasons studied. Among the climatic parameters, THI had significant (P < 0.05) influence on sperm quality. The proportion of Sertoli cell in the testicular cytology had a significant and positive relationship with RH, THI and day length. It was concluded that seasonal variations are less evident in terms of spermatogenesis and semen quality in Alpine X Beetal crossbred bucks reared under subtropical climatic conditions.

Seasonal Variations in Semen Parameters of Zulu Rams Preserved at 10°C for 72 H During Breeding and Non-Breeding Season

“…Benia et al (2018) obtained similar results in Ouled-Djellal rams. However, other authors (Barkawi et al, 2006;Gündoğan, 2007;Azawi and Ismael, 2012;Golher et al, 2018;Hedia et al, 2019) reported huge seasonal variation on spermatozoa concentration, with breeding season recording higher concentration than non-breeding season with winter yielding lesser sperm concentration (Wang et al, 2015;Kadili et al, 2019). Noteworthy, the sperm concentration from the current study was higher than that reported by (Chella et al, 2017) in Zulu rams.…”

Analysis of Screening Results of 1012 Sperm Donors in China: A Retrospective Cohort Study of Geographic Differences in Semen Quality

“…The mean(IQR) age of all participants was 26 (23-31) years old. Among the 1012 participants, 752 were from northern China, and the median (IQR) age was 27 (23)(24)(25)(26)(27)(28)(29)(30)(31) years old; 260 were from southern China, and the median (IQR) age was 24 (22)(23)(24)(25)(26)(27)(28)(29) years old. About 94% of the subjects were from Han ethnic group.…”

“…Some analysts speculate that the high temperatures may affect testicular spermatogenesis. However, the study conducted by Golher et al suggested that the sperm function parameters of crossbred bucks, which were reared in subtropical climate, did not show any difference in different seasons, which may be related to the advanced testicular temperature regulation mechanism in the body [31] . Our study did not record the seasons when volunteer donated their semen due to limited statistical conditions, but we will incorporate this factor into statistics in future studies.…”

Seasonal Variations in Semen Quality of Pasundan Bulls in their Native Tropical Environment

“…While in the tropical region, since the photoperiod is almost similar throughout the year, other factors such as temperature and relative humidity probably become two significant contributors in the semen quality variation (de Castro et al, 2017). In more recent, sunshine duration, which defined as the duration of direct sunshine exposure to the land surface, also reported as one factor which could influence semen quality (Golher et al, 2018). All of these-mentioned factors should be discussed to provide in-depth knowledge of seasonal effects on semen quality.…”