BIOAVAILABILITY OF COPPER IN PIG FECES

Abstract

A chick growth assay was conducted to determine the bioavailability of copper in pig feces. Feces were collected from young pigs fed a 650 mg Cu kg⁻¹ diet. After drying, they were fed to chicks to provide graded intakes of copper. Graded levels of CuSO₄∙5H₂O were also fed, and the increase in liver copper concentration was compared between the two sources. Dietary addition of 500 mg Cu kg⁻¹ diet as CuSO₄∙5H₂O depressed chick growth and increased liver copper concentration 42-fold. Addition of 748 mg Cu kg⁻¹ diet as dried pig feces had no effect on growth and increased liver Cu concentration only threefold. These data suggest that the Cu in pig feces is poorly available. Relative to oral CuSO₄ providing 250 mg Cu kg⁻¹ diet, orally ingested fecal Cu exhibits a bioavailability no greater than 35.6%. Key words: Swine, chickens, inorganic copper, fecal copper, copper bioavailability