| Cadmium is known as a harmful metal to animal health. Researches demonstrated that cadmium poison could lead torespiratory hypofunction, ataxia, anaemia, cardiovascular diseases, organ damage, osteoporosis, hypoimmunity, cancer and death, etc. Nowadays, the pollution of cadmium to nature is widely spread. In some polluted region in China, the cadmium content of feed was up to 1.13mg/kg-5.12mg/kg, severely more than the permitted content of feed. Additionally, due to the undegradability and long half-times, cadmium will throw great threat on animal health. Recently, scientists paid more attention to the latent effects of cadmium on male fertilities, including aquatic animal and human being. Studies indicated that cadmium poison could lead to lower fertilities of male livestocks, and it might be related to the ED(Erectile Dysfunction) of men.To deeply discover the effects and mechanism of cadmium poison on reproductive system of male animals, the effects of cadmium on male fertilities, cadmium distribution in the organs, the cadmium toxicity on testicle and accessory sex gland, the effects of cadmium on sex hormone, the effects of cadmium on Leydig cell were first systemically studied in this paper in China, under the exposure of cadmium, especially the cadmium exposure of chronic digestive tract. And more, the mechanism of cadmium on male fertility dysfunction was studied from the following aspects: the changes of sex hormone, the changes of biochemical indice, the changes of oxidative and antioxidative system, the breakdown degree of DNA single chain, the profiles of induced apoptosis, the existing status of cadmium in testicle (relationship with MT), etc. The main research methods: animal reproduction tests, the observation of microstructure and ultra-microstructure, the changes of sex hormone by radioimmunosorbent and histochemical methods, the determination of special enzymes by biochemical method, the determination of cadmium levels by atomic absorption spectrophotometry, the analysis of the breakdown degree of DNA single chain by single cell gel electrophoresis, the analysis of apoptosis by morphology and TUNEL methods, the protein isolation by gel chromatography, and the protein identification by amino acid analysis. The results showed that:chronic cadmium exposure via drinking could significantly affect fertilibility of male animals due to the toxicity to animal sperm, and the toxicity depended on the doses and time: with the increased doses of cadmium, the weight of epididymis tail, the motility of sperm, the sperm density and living sperm ratio decreased, whereas the abnormal sperm in epididymis tail of rat increased, and the effects of cadmium toxicity on the the Spermatogenesis of the rat which was exposed by cadmium beginning from sex immature were more than from sex mature . the pregnant rate and average live new-born offspring of female rat inseminated by the cadmium-treated male rats were decrease, with the increase of cadmium doses and time.however, no significant effects on the growth of offspring were observed when male rats were exposed chronically to cadmium via drinking. The research demonstrated that there were no significant effects on the offspring sex distribution when male animals were exposed chronically to cadmium via drinking. Under the condition of chronic cadmium exposure via drinking, the main reasons of the effects on the change of sperm morphology and the sperm formation dysfunction were not the direct toxic effects of sperm cells.The effects of sex control of cadmium were not achieved by directly affect the reproductive system of male animals or sperms, but at the process the fertilization in female animals.Under the chronic exposure to cadmium via drinking water, cadmium was poisonous to rat sex and accessory sex gland, and could lead to structural changes of them, and the change was dose-dependent. Comparatively, male reproductive organs were more sensitive to the cadmium than livers and kinneys; testicles were more sensitive than epididymis, glandula ves...
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