The effects of feeding high iron and high zinc diet to hens on the iron and zinc content in egg and egg quality

To evaluate the effects of high iron and high zinc diet on iron and zinc content in egg and egg quality 278 day old Lohmann laying hens were fed with containing Fe 25 mg·kg -1 , Zn 60 mg·kg -1 diet (control group), Fe 525 mg·kg -1 , Zn 605 mg·kg -1 diet (groupⅠ) and Fe 1 025 mg·kg -1 ,Zn 1210 mg·kg -1 diet(groupⅡ) for 8 weeks. Observations were made on production performance, egg quality and egg iron and zinc contents. The results showed that as compared with control group the yolk iron in groupⅠ and groupⅡ were increased by 42.7% and 84.8%, yolk zinc contents by 55.8% and 89.8%, respectively. Plasma iron levels in groupⅠand groupⅡ were higher by 81.0% and 126.4% than those in control group. And plasma zinc contents in groupⅠ and groupⅡ were enhanced by 59.6% and 86.1%. However, there were no significant differences in egg quality between control group and groupⅠand groupⅡ. But, the production performance of hens was decreased by high iron and high zinc diet. Those results suggested that the diet with high iron and high zinc could cause much higher iron and zinc contents in egg.