Accumulation of zinc in egg yolk, ovarian follicles and organs after forced resting by high dietary zinc

Abstract

1. Eighteen Warren SSL hens of 71 weeks of age were forced-moulted by ad libitum feeding of a high-zinc diet (10,000 ppm zinc for 2 days followed by 5,000 ppm zinc-supplement diet for 4 days). From the start of the treatment, eggs were collected and 3 hens were slaughtered on days 0, 2, 3, 4, 5 and 6 of the study. 2. Zinc analyses were carried out on the different components of the eggs and on liver, pancreas, kidney, different yolky follicles of the ovary and various segments of the oviduct. 3. Seven-, six- and threefold increases in zinc concentration were found in pancreas, liver and kidney, respectively. 4. The shell gland and isthmus, but not the magnum, also showed slight but significant increases in Zn content. 5. Zinc accumulation was also high and almost identical in ovarian follicles F1 to F4 but slightly less in F5 and F6 follicles. 6. In the egg, a significant increase in zinc concentration was only observed in the yolk.

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)

“…The high zinc concentration in egg yolk at peak of the second production cycle in the zinc-induced molted group resulted from zinc supplementation during the molting period. Similar results have been reported by Verheyen et al (1990) that zinc-induced molting (zinc supplementation 10 000 ppm for 2 days and 5000 ppm for 4 days) elevates egg yolk zinc concentration. However, in the current study, the concentration of egg yolk zinc was only elevated at peak of the second production cycle in zincinduced molted group.…”

“…However, Kaya et al. (2001) and Verheyen et al. (1990) reported that egg albumin zinc concentration did not increase after dietary zinc supplementation and zinc‐induced molting respectively.…”

“…The high zinc concentration in egg albumin at 5% and at peak production in the zinc-induced molted group resulted from the zinc supplementation during the period of the molting. However, Kaya et al (2001) and Verheyen et al (1990) reported that egg albumin zinc concentration did not increase after dietary zinc supplementation and zinc-induced molting respectively. The high concentration of copper in egg albumin at 5% and at peak of the second and third production cycle indicated that zinc-induced molting might have induced more production of metal binding egg albumin proteins particularly the ovalbumin.…”

High doses of dietary zinc induce cytokines, chemokines, and apoptosis in reproductive tissues during regression

“…Zinc tends to accumulate in the reproductive system when birds are induced to molt by zinc feeding (McCormick and Cunningham 1984;Verheyen et al 1990). However, the consequence of high levels of zinc accumulation in the reproductive tissues during the induced molting is poorly understood.…”

Essential elements content of hen egg-white in Markazi province (Iran)

“…Verheyen et al (1990) and Stahl et al (1986) reported considerable increase of zinc content in egg yolk after adding zinc supplement to the feed, while Skřivan et al (2005) and Kaya et al (2009) reported decrease of zinc content in egg yolk after adding supplements in feed. Palafox & Ho (1980) reported that adding 20 000 pg Zn/g for five days decreased the zinc content and egg production for a few days.…”