Effect of Corn Oil on Metabolic Efficiency of Energy Utilization by Chicks

Abstract

Studies were made of the tissue composition and tissue energy gains of chicks receiving equal intake of metabolizable energy and all other nutrients from diets containing 2.5, 12.5 and 22.5% corn oil substituted isocalorically for glucose. Tissue energy gains per unit of metabolizable energy intake increased as the dietary level of corn oil was increased. It is concluded that replacement of dietary carbohydrate with corn oil increases the metabolic efficiency of energy utilization by chicks. Increases in tissue energy were due solely to increased fat content. Nitrogen retention measured as gain in tissue protein was reduced in one experiment but was unaffected in a second experiment by feeding high levels of corn oil. However, no significant effect of corn oil on growth rate was observed, indicating an inverse correlation between tissue fat deposition and water retention. Based on results reported in the literature for the chick and other species, it appears most probable that the beneficial effect of corn oil on efficiency of energy metabolism is mediated through the heat increment component rather than the basal component of heat production. Further studies will be necessary to determine whether this effect is a general property of well-utilized fats or is due to unidentified substance present in corn oil.