EFFECT OF COPPER ON THE UTILIZATION OF RAW SOYBEANS BY MARKET PIGS

Abstract

Three trials, involving a total of 160 Yorkshire SPF pigs, were conducted to evaluate the effect of the addition of copper (Cu) and/or raw ground soybeans (RGS) to diets of market pigs. The addition of RGS to pig diets resulted in decreased feed consumption and slower growth rate when pigs were fed ad libitum. When feed intake was restricted, rate of gain was not influenced by RGS. Dietary Cu supplementation resulted in an improved rate of gain and feed consumption when fed ad libitum, with a greater response exhibited by pigs fed diets containing RGS. Prediction of rate of gain for a constant feed intake suggested that a portion of the Cu effect is due to increased feed intake. Copper supplementation resulted in increased liver Cu, and decreased liver iron. Increased levels of dietary RGS resulted in decreased liver iron. An RGS × Cu interaction was observed in kidney Cu, in which higher dietary levels of both RGS and Cu were accompanied by decreased kidney Cu content. Increased levels of dietary RGS caused a decrease in nitrogen digestibility.