抄録
In this study, vitamin D 3 (VD 3 ) enriched diets were fed to breeding quails and the feeding effects on their chicks were investigated.
The content of VD 3 in a diet was enhanced to 1800 IU/kg VD 3 and eggs and chicks resulting from breeding quails fed the VD 3 -enriched diet were analyzed. Eggs were analyzed for VD 3 and 25-hydroxy-VD 3 concentrations in the yolk and for Ca concentrations in the eggshell and eggshell membrane. Chicks were dissected within 24 hours of hatching and then body and liver weights were determined. Livers were sampled and the expression levels of genes involved in the metabolism of VD 3 were measured in the livers.
Feeding breeding quails with the VD 3 -enriched diet tended to decrease the VD 3 concentration in the egg yolk, but the feeding tended to increase the weight of the eggshell and eggshell membrane. This suggests that enriching VD 3 intake in breeding quails may promote eggshell formation. Furthermore, although no difference was observed in the growth of day-old chicks between the test and control groups, the expression level of CYP2R1, an enzyme that hydroxylates VD 3 at position 25, in the liver of the test group was higher than that of the control group, suggesting that feeding breeding quails with a VD 3 -enriched diet may enhance VD 3 metabolism in chicks. However, the mechanism by which VD 3 fortification for breeding quails increases CYP2R1 expression in chicks is unknown, and further studies, including the measurement of blood 25-hydroxyvitamin D 3 levels in chicks, are needed.
