Effects of zinc on male sex hormones and semen quality in rats

This study assessed the effects of zinc on male sex hormones and semen quality in male albino wistar rats. Forty rats weighing between 150- 210g, grouped into 5 of 8 rats each, were used for the research that lasted for six weeks. Group I, the control group, received normal rat chow and water ad libitum. The four test groups II-V, received 20g, 40g, 60g and 80g of zinc sulphate mixed with their rat chow respectively in addition to water for six weeks. Blood samples were collected and assayed for Luteinizing hormone (LH), follicle stimulating hormone (FSH), Prolactin (PL), testosterone (T), progesterone and oestradiol. Semen was also analysed for sperm motility, sperm count and morphology. Results showed statistically significant decrease in serum levels of follicle stimulating hormone (FSH) (p< 0.05) in groups II and IV with mean values of 0.10±0.00 and 1.20±0.00 respectively when compared with the control (1.10±0.10). The results also revealed statistically significant increase in the serum levels of testosterone in groups II, III and IV with mean values of 3.60±1.40, 4.5±0.30 and 0.80±0.70 respectively when compared with the control with a value of 0.35±0.15. The increase in testosterone levels were dose dependent as there were consistent increment in groups II and III after which the levels decreased with increasing zinc concentrations. There was statistically significant dose dependent decrease in sperm motility and morphology in the test groups compared with the control (p<0.05). In conclusion, zinc sulphate has some significant positive effects on male sex hormones and sperm quality at doses within physiological levels but harmful at higher doses.