Distribution and Fractionation of Zinc and Copper in Poultry Litters Across North Carolina

Abstract

ABSTRACT Zinc (Zn) and copper (Cu) are necessary micronutrients for crop production. However, excess Zn and Cu applied through land application of manures can result in Zn and Cu toxicity, reducing yields. With many integrators and little information on the formulation of poultry feeds in North Carolina (NC), it is difficult to predict the fractionation of Zn and Cu in litters generated at facilities, as the form of Zn and Cu determines mobility and bioavailability. Therefore, statewide data from the NC Department of Agriculture and Consumer Services was analyzed to determine regional variation of total Zn and Cu. The results showed a significant effect of the region on the total Zn and Cu among the three production regions in the state. Additionally, 11 broilers and broiler breeder litter samples were analyzed to determine the distribution of Zn and Cu in acid soluble, reducible, oxidizable, and residual fractions. Total Zn and Cu averaged 675 mg/kg and 629 mg/kg, respectively. There was a significant interaction between the region and Zn concentration in the fractions. However, there was no region interaction when converted to a percentage of the sum of the fractions, indicating Zn partitions similarly across a wide range of concentrations and 37%, 40%, 21%, and 0.6% was found in the acid soluble, reducible, oxidizable, and residual fractions, respectively. Region did not have an effect on Cu fractionation, with 26%, 8%, 67%, and 2% of Cu in the acid-soluble, reducible, oxidizable, and residual fractions, respectively. Results indicate greater bioavailability and mobility potential for Zn as compared to Cu.