Comparison of the fast-induced and high dietary zinc-induced molting: trace elements dynamic in serum and eggs at different production stages in hens (Gallus domesticus).

A number of 252, 70 week old, single comb white leghorn hens at the end of their first production cycle were divided into two groups: group-I; molted by fasting and group-II; by high dietary zinc to obtain the second and third production cycle. Sampling was carried out at 5%, peak and end of the second production cycle and at 5% and peak of the third production cycle. Serum zinc decreased at the peak of the second production cycle, while increased at the 5% of the third production cycle in zinc-molted group. Serum copper and manganese increased at the 5% and peak of the second production cycle in zinc-molted group. Egg albumin zinc and copper increased at the 5% and peak of the second as well as third production cycles in zinc-molted group. Egg albumin manganese increased at 5% during the second production cycle in fasting molted group. Egg yolk zinc increased at the peak of the second production cycle in zinc-molted group. Egg yolk copper increased at the 5% of second production cycle but decreased during the third production cycle in zinc-molted group. Egg yolk manganese increased at the 5% and at the end of the second production cycle in zinc molted group. Egg yolk manganese and iron decreased during the third production cycle in zinc-molted group. Eggshell zinc decreased at the end of the second production cycle in the zinc-molted group, while eggshell copper increased at the peak of the second as well as third production cycles in fasting molted group.