Short-Term High Level Zinc Feeding and Tissue Zinc Concentration in Mature Laying Hens

Abstract

Two trials were conducted to study the effects of high dietary Zn on tissue Zn accumulation and depletion in laying hens. Hens laying at approximately 60 to 70% were fed a diet containing 20 g Zn as ZnO/kg diet (as fed) for 4 days. For the remaining 18 days, hens were fed the same diet without the 20 g added Zn/kg diet. Ten hens were killed at initiation of the experiment (Day 0), and liver, kidney, and pancreas were obtained for Zn analysis. On Days 1, 2, 3, 4, 10, 16, and 22, similar samples were obtained from 10 hens. Feeding high Zn for 4 days caused a reduction in ovary and oviduct weight by Day 10. Liver, kidney and pancreas Zn concentrations increased approximately 10, 3, and 25-fold, respectively, in birds following 4 days of feeding the high Zn diets. The liver and kidney Zn concentrations returned to pretreatment concentrations within 18 days after the birds were fed the control diets (Day 22). The pancreas maintained higher Zn concentrations in comparison with the other tissues following withdrawal of the high Zn diet.

Pancreatitis in wild zinc-poisoned waterfowl

“…The proportional increase in Zn concentrations in kidneys and pancreases was greater than that in livers of dosed birds (Gasaway & Buss, 1972;Levengood et al, 1999). Zn concentrations were higher and more variable in the pancreas than in the liver of Zn-poisoned birds and, when dietary concentrations of Zn were reduced, Zn concentrations remained longer in the pancreas compared with other tissues examined (Williams et al, 1989). Tissue Zn concentrations in chickens drop rapidly after exposure returns to normal (Oh et al, 1979).…”

Dietary Strategies to Improve Nutritional Value, Oxidative Stability, and Sensory Properties of Poultry Products

“…The addition of zinc into the poultry diet at doses of 20 g/kg feed reduced feed intake and body weight (McCormick and Cunningham, 1987;Williams et al, 1989). Furthermore, the addition of zinc from 0.2 to 20 g/kg Downloaded by [University of Connecticut] at 12:47 07 October 2014 chicken feeds during short periods of time (less than 3 weeks) caused the increase of this element in liver, kidney, pancreas, and spleen (Emmert and Baker, 1995;McCormick and Cunningham, 1987;Park et al, 2004;Sandoval et al, 1998;Williams et al, 1989).…”

“…The addition of zinc into the poultry diet at doses of 20 g/kg feed reduced feed intake and body weight (McCormick and Cunningham, 1987;Williams et al, 1989). Furthermore, the addition of zinc from 0.2 to 20 g/kg Downloaded by [University of Connecticut] at 12:47 07 October 2014 chicken feeds during short periods of time (less than 3 weeks) caused the increase of this element in liver, kidney, pancreas, and spleen (Emmert and Baker, 1995;McCormick and Cunningham, 1987;Park et al, 2004;Sandoval et al, 1998;Williams et al, 1989). Zinc content in the skeletal muscle can be increased in young chicks (≤ 3 weeks of age) by dietary supplementation, but when the animal gets older a poor linear regression between dietary zinc supplementation and muscle zinc content was observed (Sandoval et al, 1998), and at the end of the growing period of broilers (42 days old) the supplementation has no effect on zinc content in meat with skin (Bou et al, 2004;Bou et al, 2005c).…”

Copper and Zinc Nutritional Issues for Agricultural Animal Production

“…When mature laying hens were fed 20,000 ppm Zn for 4 days, ovary and oviduct weights were reduced by 10 days. By 18 days, liver and kidney Zn concentrations returned to pre-treatment concentrations, but the pancreas maintained its high concentration [ 155 ]. This is a means of forced rest [ 156 ].…”