Effect of Dietary Copper Sources (Cupric Sulfate and Cupric Methionate) and Concentrations on Performance and Fecal Characteristics in Growing Pigs (Report‪)‬

INTRODUCTION Copper is added routinely to the diets of growing swine. The NRC (1998) requirement of copper for pigs is only 5 to 6 ppm. When fed with 100 to 250 ppm, this element was determined to be effective for growth promotion with antibacterial activity in pigs (Barber et al., 1955; Braude, 1967, 1975; Cromwell et al., 1981). Cromwell et al. (1989) and Bowland (1990), however, have suggested that copper stimulated growth was associated with the solubility of the copper source; hence, copper must be available for absorption. The most frequently utilized dietary copper supplement in the animal diet is inorganic Cu, usually in the form of copper sulfate (CuS[O.sub.4]-5[H.sub.2]O). Copper, occurs in the organic forms of chelates, complexes, or proteinates, and like other organic trace minerals, is often considered as an alternative to inorganic sources in animal diets. This is probably attributable to improved absorption, which enhances the efficiency of use (Downs et al., 2000; Yu et al., 2000; Guo et al., 2001). Baker and Ammerman (1995) reported that the relative bioavailability estimates of organic Cu sources ranged between 88% and 147% of the response to cupric sulfate in poultry, swine, sheep, and cattle. It has also been observed that such high levels of Cu supplementation result in its high excretion in the feces (Paik et al., 1999). The presence of high Cu concentrations in the feces inhibits the normal fermentation process, and the accumulation of Cu in the soil causes environmental concerns. If organic Cu in the form of Cu-methionine (CuMet) chelate is more readily absorbed, this may save copper resources, decrease Cu excretion, and ameliorate the environmental concerns attendant to Cu dietary supplementation.