Detrimental impacts of heavy metals on animal reproduction: A review
Ranjeet Verma, Kennady Vijayalakshmy and Vikas Chaudhiry
Lead, cadmium, mercury and arsenic are often referred to as "heavy metals" and are highly toxic to animals and human. The indiscriminate human activities like rapid industrialization, overgrowing urbanization and environmental manipulation have drastically altered the biogeochemical cycles. Aggregation with polluted water tends to pollute the agricultural soil and the crops that grow in this soil will be having a more heavy metal accumulation. These crops that have been used by animal for grazing or feed purpose will be accumulated with heavy metals that can reach the animal body, in other ways heavy metals can directly reach the animal body by means of drinking contaminated water. Prolonged exposure to heavy metals such as lead, mercury, cadmium and arsenic causes deleterious health effects in animals. Heavy metal primarily affects the liver, kidney, brain and other body systems. Lead, mercury, arsenic and cadmium are the most common heavy metals that are found in industrial and domestic wastages. With exposure to heavy metals, reproductive system shows the chronic type of toxicity andproduces cellular impairments at both structural and functional level. It could cause impairment in steroidogenesis, hormonal regulation, gametogenic process, affect leydig cells and spermatogenesis in males and granulosa cells, theca cells in females; placental growth, pregnancy rate and development of fetus in females. Animals that are reared near the area that are having extreme level of heavy metals contamination are highly prone to infertility problems.