PROPHYLACTIC ROLE OF DIETARY ZINC AGAINST CADMIUM TOXICITY IN BROILER CHICKS WITH SPECIAL REFERENCE TO CUMULATIVE EFFECT OF CADMIUM ON THE LEVEL OF SOME ELEMENTS IN VARIOUS TISSUES

The objective of the present study is to detect in appropriate way evidence of cadmium toxicity as a consequence of exposure to sublethal doses added to drinking water at the concentration level of 10 and 100 ppm singly or in combination with a low concentration of zinc(5ppm) as daily supplement to chicks for 30 days. The body gain in 10 and 100 ppm Cd-treated chicks was significantly decreased at one month. Moreover, the percent of food and water consumption were reduced. Addition of zinc (5ppm) to 100 ppm Cd-exposed chicks enhanced the gain in body weight as well as food and water consumption.
The erythrocytic count, haemoglobin content and hematocrit values were significantly decreased in all cadmium-treated groups. Zinc supplementation improved the haematological pictrue to slight extent. The serum of Cd-treated chicks showed a Significant increase in AST, ALT, Alkaline phosphatase and total bilirubin levels. On the other hand, total proteins were decreased. The cadmium level in liver, kidneys, skeletal muscle, small intestine and bone exceeded over controls in all treated chicks. Zinc supplementation (5ppm) decreased the cadmium accumulation in the investigated tissues. Zinc levels were reduced in bone and increased in liver, kidneys, skeletal muscle and small intestine. The copper content was decreased in kidneys and increased in the skeletal muscles. Significant decrease in the iron content was observed in the liver, kidneys, small intestine and bone.
It could be concluded that dietary zinc plays a prophylactic role against cadmium toxicity.