The Effect of Low Dose of Cadmium on Growth, Reproduction and Chicken Viability

Cadmium (Cd) is considered to be a highly polluting heavy metal with toxic effects on health and reproduction. In this study, the effects of low dose cadmium on growth, reproductive properties, and egg properties were studied. Cadmium as cadmium chloride (CdCl₂) at a dose of 3 mg Cd.kg⁻¹ was added as a feed supplement. The following parameters were evaluated: body weight, egg production, fertility, hatching, embryo and chick mortality, and egg quality characteristics. After 2 months of exposure to low doses of cadmium, the body weight increased in the cocks and did not change in the laying hens. Egg production was not affected, while fertility increased. The values of egg weight and hardness, thickness and shell weight were significantly higher (P < 0.05). The embryo mortality in the experimental group was lower (6.5 % vs. 12.8 %) compared to the control group. The hatching was significantly higher (P < 0.05) and the loss in 7 day old chickens was similar to that in the control group. Although the toxic effects of cadmium on reproduction and accumulation in poultry bodies have been generally described, low-doses of cadmium given to adult hens and cocks has improved the reproductive parameters and qualitative properties of laying hen eggs. The results related to the reproduction and quality of eggs obtained in this study have the characteristics of the hormetic effects of low cadmium uptake.