The effect of dietary zinc level upon the efficiency of vitellogenin synthesis by male quail
Manipulation of dietary zinc produced a different body zinc status in male Japanese quail during 3 weeks of treating period. After intramuscular injection with 8μmol/100g body weight of estradiol-17β, Japanese quail were sacrificed and vitellogenin (phosphoprotein) production was assessed in these birds by analyzing plasma for protein-bound phosphorus concentrations (PBP). Plasma PBP concentrations of estrogen-injected male quails increased from undetectable values for control birds to O.66mg/ml for high-zinc birds and O.42mg/ml for low-zinc birds. About 36% loss of vitellogenin synthesis was associated with the consumption of the zinc-deficient diet. Plasma zinc concentrations also increased on the estrogen injection because of the zinc-binding property of vitellogenin. The extra zinc ions in the plasma were considered to be come from the body zinc pools. Liver as well as other major tissues was believed to act as a reservoir of zinc for egg development but it was not observed that liver was the major source of the extra zinc in the plasma.