Changes In Trace Element Contents And Morphology In Metatarsals Of Duck Exposed To Molybdenum Or/and Cadmium

The object of this study was to investigate the changes of trace elements' contents and morphology in bones of duck when exposed to Mo or/and Cd.360 healthy 11-year-old ducks were selected to six groups with 60 ducks in each group. They were control group, group i(15 mg/kg Mo), group ii(100 mg/kg Mo), group iii(4 mg/kg Cd), group iv(15 mg/kg Mo + 4 mg/kg Cd) and group v(100 mg/kg Mo+ 4 mg/kg Cd). Hexaammonium molybdate([(NH4)6Mo7O24·4H2O]) and cadmium sulfate(3Cd SO4·8H2O) were selected as sources of Mo and Cd respectively. On the 30 th, 60 th, 90 th and 120 th days, blood, excretion and metatarsals were collected to determine alkaline phosphatase(AKP) activity and the contents of Mo, Cd, calcium(Ca), phosphorus(P), copper(Cu), iron(Fe), zine(Zn) and selenium(Se) in serum, metatarsals and excretion. In addition, metatarsals were also subjected to histopathological analysis with the optical microscope and radiography. The results are as following:1. With the Mo concentration increasing in diet, Mo content in serum and metatarsals was increased significantly of Mo treated groups(P<0.01), it was in a dose-dependent manner.2. Dietary of Cd could increase the Cd content in serum and metatarsals, there was significant difference between control group and Cd group(P<0.05 or P<0.01).3. Mo and Cd significantly decreased P content in serum, while Ca content in serum had no significant change in comparison with control group(P>0.05), Ca and P contents significantly decreased in metatarsals(P<0.05). Ca and P contents in excreta of groups iv and v were significantly increased(P<0.05).4. High dietary of Mo increased Cu content in serum significantly(P<0.01), but Cu content in serum of other experimental groups was decreased significantly(P<0.05), Cu content in metatarsals of all experimental groups was significantly decreased(P<0.05) as compared to control group.5. Mo and Cd had no significant effects on Fe, Zn contents' changes in serum and metatarsals, difference among experimental groups was not significant(P>0.05).6. Except the group i, Se content in metatarsals of all experimental groups were significantly decreased as compared with control group(P<0.01). Mo, Cd and the combination of the two elements could increase the Se content in serum of group ii, while there was no significant change in other experimental groups(P>0.05).7. Mo, Cd and the combination of the two elements could increase the alkaline phosphatase activity significantly(P<0.05 or P<0.01), but there was no significant change in group i compared with control group(P>0.05).8. Mo and Cd combination resulted in trabecular number decrease, structural deformity, X-ray penetrable increased, and bone mineral content decrease, but average bone density of each treated group had no significant changes(P>0.05).The findings suggested that dietary of Cd or/and Mo could lead to bone damage in ducks through disturbing the balance of Ca and P in body, and the two elements could antagonize homeostasis of Cuand Se in bones.Osteoporotic lesions, less and thinner trabecular bone were observed in combination groups,moreover,the two elements showed a possible synergistic relationship.