Protection against zinc deficiency by prior excess dietary zinc in young Japanese quail

Abstract

Three experiments were designed to determine whether an excess of zinc during the first week of life would afford any protection to young Japanese quail during a subsequent period of zinc deprivation. Day old birds of both sexes were fed an adequate purified diet containing soybean protein with requirement (25-30 mg/kg of diet) or higher levels of zinc for 1 week. The zinc level was reduced during the second week to the deficient level of 1 mg/kg of diet, except for the controls which continued to receive an adequate or higher level of zinc (25, 30, or 75 mg/kg of diet). With this low zinc intake, birds that received an initial level of zinc in excess of requirement grew significantly better (body weight and length of primary wing feathers) than those that initially received the required amount of zinc. Data on zinc content of liver, breast muscle, tibia, and whole body retention suggest that bone may store zinc consumed in excess of requirement and that this zinc may be available for utilization during a subsequent period of zinc deprivation in a growing animal that has rapidly remodeling bones.