Tissue Bioaccumulation and Toxicopathological Effects of Cadmium and Its Dietary Amelioration in Poultry-a Review.

Cadmium (Cd) has been recognized as one of the most toxic heavy metals, which is continuously discharged into environments through anthropogenic (industrial activities, fertilizer production, and waste disposal) and natural sources with anthropogenic sources contributing greater than the natural sources. Therefore, Cd concentration sometimes increases in feeds, fodders, water bodies, and tissues of livestock including poultry in the vicinity of the industrial areas, which causes metabolic, structural, and functional changes of different organs of all animals. In poultry, bioaccumulation of Cd occurs in several organs mainly in the liver, kidney, lung, and reproductive organs due to its continuous exposure. Intake of Cd reduces growth and egg laying performance and feed conversion efficiency in poultry. Chronic exposure of Cd at low doses can also alter the microscopic structures of tissues, particularly in the liver, kidney, brain, pancreas, intestine, and reproductive organs due to increased content of Cd in these tissues. Continuous Cd exposure causes increased oxidative stress at cellular levels due to over-production of reactive oxygen species, exhausting antioxidant defense mechanisms. This leads to disruption of biologically relevant molecules, particularly nucleic acid, protein and lipid, and subsequently apoptosis, cell damage, and necrotic cell death. The histopatholocal changes in the liver, kidneys, and other organs are adversely reflected in hemogram and serum biochemical and enzyme activities. The present review discusses about Cd bioaccumulation and histopathological alterations in different tissues, pathogenesis of Cd toxicity, blood-biochemical changes, and its different ameliorative measures in poultry.