Effect of season on bovine seminal plasma proteins in Thailand.

I Lima Verde,A Johannisson,T Nongbua,J.M Morrell,S Karkehabadi

doi:10.1016/j.jtherbio.2020.102576

Abstract

Although season has been shown to affect bull sperm quality and fertility in some studies, the effect of season on seminal plasma proteins has not been examined. In the present study, seminal plasma proteins were analysed by Fast Protein Liquid Chromatography (FPLC), to separate the phosphorylcholine-binding proteins and heparin-binding proteins from the other proteins. Semen samples were collected from bulls in three seasons: winter, summer and the rainy season. Sperm quality was analysed by flow cytometry and computer assisted sperm analysis, and further aliquots of semen were used to prepare the seminal plasma for FPLC. Meteorological data were available from a location close to the bull station. There were slight differences in sperm kinematics between seasons, but other parameters of sperm quality were not different. Minor differences in the phosphorylcholine-binding proteins were detected according to season, being lower in summer than in winter or in the rainy season, although there were no changes in the heparin-binding proteins. Temperature, humidity and rainfall differed between winter and the rainy season, but no differences were observed between summer and the rainy season except in the temperature humidity index (THI). However, the THI was above the threshold indicative of heat stress in all seasons, which could explain why few seasonal differences in protein composition were detected in this study. Alternatively, the bulls could have been well-adapted to heat stress. In conclusion, there were only slight differences in bull sperm quality and seminal plasma proteins between seasons during this study.

Highlights

Several studies have reported that bull sperm quality is affected by season, especially in tropical climates (e.g. Koivisto et al, 2009; Snoj et al, 2013), and in more temperate regions (Valeanu et al, 2015; Sab es-Alsine et al, 2017)
Non-heparin-binding proteins were eluted as the three first peaks (F1 þ F2 þ F3); phosphorylcholine-binding proteins and heparinbinding proteins were eluted as peaks F4 and F5 (Fig. 2)
Bulls in temperate climates usually show changes in sperm quality for several weeks after changes in temperature and humidity (Malama et al, 2012; Sab es-Alsina et al, 2019); our results indicate that the bulls that are well adapted to their environment show very little effect on sperm quality due to seasonal changes in climate

Summary

Introduction

Several studies have reported that bull sperm quality is affected by season, especially in tropical climates (e.g. Koivisto et al, 2009; Snoj et al, 2013), and in more temperate regions (Valeanu et al, 2015; Sab es-Alsine et al, 2017). Bovine SP is a complex fluid to support sperm movement and provide transport for the spermatozoa into the female genital tract during mat ing (Maxwell et al, 2007a; Poiani, 2006; Suarez and Pacey, 2006). It is mostly composed of secretions from the accessory sex glands together with a small volume of fluid from the testis and epididymis (Maxwell et al, 2007; Moura et al, 2007). Minerals, elec trolytes, hormones and enzymes (Poiani, 2006) and has a major function in stimulating and supporting spermatozoa, by providing nutrients and a protective environment, and by enhancing sperm motility in the female (Maxwell et al, 2007a; Poiani, 2006)

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Results

Conclusion