THE EFFECT OF COMBINED ZINC-CADMIUM INJECTION IN OVO ON THE ACTIVITY OF INDICATIVE HYDROLASES IN ORGANS OF NEWLY HATCHED CHICKS

The aim of experiment was to examine if embryotoxic effect of cadmium, evaluated by using selected lysosomal hydrolases as biomarkers, can be reduced by simultaneous zinc in ovo administration. Developing chicken eggs (n=42 eggs per group, 4th day of incubation) were injected by 50 mu L of 0.7% NaCl solution containing cadmium ions (0 or 50 nmol per egg) and/or zinc ions (0, 100 or 500 nmol per egg). The Cd and Zn distribution in tissues (liver and kidneys) of 1-day old chicks was examined by ICP-OES method, while the activities of lysosomal hydrolases: N-acetyl-beta-D-glucosaminidase (NAG) and beta-D-mannosidase (beta-MAN), and arylsulfatase (ARYL) were tested spectrophotometrically. The hatchability of control group and chicks treated by combination of 50 nmol Cd and 500 nmol Zn per egg was about 61% (comparable to the control group 61.9%) while the hatchability of remaining groups was from 30 to 50% lower (P <= 0.05). Cd accumulation in liver and kidney of chicks exposed to this metal increased significantly in both tissue to 0.07 mu g/g, whereas in the presence of higher zinc dose it was reduced to 0.04 and 0.05 mu g/g, respectively. Moreover the increase in activity of lysosomal hydrolases induced by treatment of separately Cd and Zn was abolished by simultaneous administration of both ions (P>0.05). Concluding, supply of Zinc seems to protect against Cd-induced disorders during chick embryo development.