Since the discovery of high concentrations of zinc in semen in 1921, the medical profession has conducted numerous studies on trace elements in semen and seminal plasma, and found that there are more than ten kinds of trace elements measured in semen or seminal plasma. The results show that trace elements are closely related to male sexual function, sex hormone secretion and reproductive system development, and that metabolic disorders of certain elements can even lead to male infertility. I. The effect of semen zinc on sperm quality Zinc is an important trace element necessary for the human body, a cofactor for many enzymes in the body, closely related to the activity of a variety of dehydrogenases in the reproductive system, and closely related to its metabolic function. The total amount of zinc in human body is 2-3g, the plasma zinc content is about 18.75-41.56mmol/L, the zinc in red blood cells is 10 times more than the plasma zinc content, the zinc content in normal men’s semen has been reported at home and abroad, influenced by the local value of zinc in different geographical environments and dietary habits, about 4.06 -6.96mmol/L, generally about 4.38mmol/L, and its zinc content is more than 100 times that of plasma zinc. There must be an important physiological significance to such a rich zinc content in seminal plasma. Studies have concluded that spermatogenesis is also more active when zinc levels in the male reproductive tract are high. Clinical studies have shown that nearly half of the male infertility patients have a semen zinc level below 0.17 mmol/L. It is inferred that low zinc is one of the causes of male infertility. 1. The relationship between zinc and sperm density It was found that the zinc content of seminal plasma in the normal group of men was significantly higher than that of the infertile group and the low sperm density group. And as sperm density decreased, their semen zinc also significantly decreased. The concentration of zinc in seminal plasma of normal fertility men increased with increasing sperm density and showed a significant positive correlation. This positive correlation between seminal plasma zinc and sperm density is related to the fact that zinc affects the secretion of gonadotropins by the pituitary gland and the spermatogenic function of the testes and influences the structure and function of the prostate gland. 2. The relationship between zinc and sperm motility Male fertility depends on the proportion and number of forward-moving sperm with normal morphology in the semen. It was found that as sperm motility decreases, the zinc in semen also decreases significantly. A positive correlation was found between the increase in sperm motility and the increase in zinc content in seminal plasma in infertile men with sperm motility below 40%. Studies have shown that zinc treatment of some male infertility can improve and increase sperm motility and restore fertility. This indicates that high zinc in seminal plasma is one of the important factors in maintaining sperm motility. Studies at home and abroad have found that zinc is directly involved in the process of sperm production, maturation, activation and energization, and it is presumed that the effect of zinc on sperm motility is mainly due to the direct action of zinc on sperm. (1) Zinc delays lipid oxidation of cell membranes to maintain cell structural stability and physiological permeability, thus enabling good sperm motility. (2) Zinc absorbed within the seminal plasma during ejaculation of sperm binds to the sulfhydryl groups in the chromatin of the cell nucleus, saving the chromatin from premature depolymerization and facilitating fertilization. From most information, high zinc is beneficial to improve the motility of spermatozoa. The relationship between zinc and total sperm count The total sperm count can decrease with the decrease of zinc level in seminal plasma. Zinc preparations for the treatment of male infertility can increase the sperm count exponentially. In short, semen zinc is closely related to sperm density, sperm vitality and sperm count. Second, the effect of semen selenium on sperm quality The role of selenium in the male reproductive process has attracted increasing attention. It is reported that semen selenium concentration of 0.63-0.87mmol/L has the highest sperm vitality, semen selenium concentration of 0.5-0.8 mmol/L has the highest sperm conception rate, semen selenium concentration below 0.46mmol/L can cause male infertility. Selenium is essential for male fertility, as it is required for the biosynthesis of testosterone and for the formation and normal development of spermatozoa. As the male gonads mature, selenium levels in the gonads rise significantly. In a group of Norwegian men with low fertility, selenium concentration in seminal plasma was positively correlated with sperm concentration. Adding appropriate amounts of selenium to the diet of infertile individuals significantly improved sperm vitality and viability and reduced sperm malformation rates. 1, the relationship between selenium and sperm structural stability selenium-deficient diet fed animals sperm body appeared structural abnormalities, poor mobility, tail has a tendency to break, thus reducing the chance of fertilization. ursini found that in the sperm mitochondrial capsule, about 50% of the capsule material is selenoprotein phospholipid peroxide glutathione peroxidase, selenium is an important component of it. In the early stage of sperm formation, PHGPx has the same peroxidase activity as other peroxidases, and as sperm mature, its peroxidase activity is gradually inactivated and eventually becomes part of the sperm mitochondrial structural protein, which has an important role in maintaining the structural and functional integrity of the sperm flagellum. 2, the relationship between selenium and spermatogenesis Selenium is also one of the components of sperm mitochondrial outer membrane selenoprotein, which can prevent and control lipid oxidation on the membrane, and has a protective effect on the cell membrane and mitochondria. If the cellular biofilm is damaged, it affects DNA replication and RNA transcription. This affects the synthesis of proteins, mucopolysaccharides and enzymes, and ultimately the formation of spermatozoa. Therefore, selenium is closely related to sperm production. Sperm function is poor in selenium deficiency, and the birth rate is higher in areas with high selenium than in areas with low selenium. In summary, the trace elements zinc and selenium have a great impact on sperm quality. Zinc is closely related to sperm density, sperm motility and sperm count; while selenium has a great role in sperm production and maintaining the stability of sperm structure. Both zinc and selenium deficiencies are considered as possible factors causing the decline of human sperm quality.