Proc. 2 nd Conf. Anim. Prod. Res. Inst., Sakha 27-29 Sep. 2005: 669-680 Animal Production Research Institute (APRI), ARC, MOLAR, Egypt. EFFECT OF DIETARY CADMIUM AND LEAD CONTAMINATION ON PERFORMANCE OF GROWING RABBITS. 1- PRODUCTIVE PERFORMANCE Gaafar, H.M.A. 1 ; A.M.A. Mohi El-Din 1 ; M.E. Omara 1 ; A.E. Abdel- Khalek 2 and M.A. Abu El-Hamd 1 1- Animal Production Research Institute, Agricultural Research Center, MOLAR, Dokki, Giza, Egypt. 2- Department of Animal Production, Faculty of Agriculture, Mansoura University. ABSTRACT Fifty growing New Zealand White rabbits (30 males and 20 females) of eight weeks age were assigned randomly into 5 similar groups. Rabbits in the control group (G1) were fed pelleted commercial diet contained 0.28 ppm cadmium (Cd) and 17.60 ppm lead (Pb) on DM basis. Diets of G2 and G3 were contaminated with cadmium chloride and lead acetate to provide final levels of 0.50 ppm Cd and 30 ppm Pb, respectively (maximum tolerable level of domestic animals, NRC 1980), and in diets of G4 and G5 to provide final levels of 0.87 ppm Cd and 58.45 ppm Pb, respectively. The obtained data showed that live body weight, average daily gain, feed intake and feed conversion of growing rabbits were not affected significantly by Cd and Pb contamination during the first 8 weeks of experiment. However, during the second 10 weeks of experiment, live body weight, average daily gain, feed intake and feed conversion were significantly (P<0.05) lower for growing rabbits fed diets contaminated with high levels of Cd and Pb (G4 and G5, respectively) than diets contaminated with low levels of Cd and Pb (G2 and G3, respectively) and the control group (G1). Final body weight and overall mean of daily gain, feed intake, feed conversion and economic efficiency of rabbits fed high levels of Cd and Pb (G4 and G5, respectively) were significantly lower (P<0.05), while mortality rate was lower than in rabbits fed low levels of Cd and Pb (G2 and G3, respectively) and in the control group (G1). Keywords: Growing rabbits, cadmium, lead, feed intake, digestibility, growth. INTRODUCTION Environmental contamination and exposure to heavy metals such as mercury, cadmium and lead is a serious growing problem throughout the world. In today’s industrial society, there is no one can’t escape from exposure to toxic chemicals and metals. In general, heavy metals are systemic toxins with specific neurotoxic, nephrotoxic, fetotoxic and teratogenic effects. Heavy metals can directly influence behavior by impairing mental and neurological function, influencing neurotransmitter production and utilization and altering numerous metabolic body processes (Neathery and Miller, 1975; Verma et al., 1978; Sharma and Street, 1980 and Mahaffey, 1983). Cadmium and lead enters air from mining, industry and burning coal and household wastes. Cadmium particles in air can travel long distances falling to