Energetic Efficiency of Corn Oil and Poultry Fat at Different Levels in Broiler Diets

The energetic efficiency of broiler finishing diets containing poultry fat or corn oil at levels of 5, 10, 15, and 20% was determined. Diets were formulated so that energy and nutrient density increased at each increment of added fat and calorie-nutrient ratios remained constant for all diets. Body weight gains were significantly greater for all diets containing added fats with no significant difference between fat sources. Feed efficiency adjusted to the same metabolizable energy (ME) and nutrient density was similar for all diets. Caloric efficiency (energy gain/energy absorbed) was slightly greater in the diets containing added fat than in the low fat control diet. Heat increment (HI) plus heat of activity (HA) corrected for intake (GE intake) was significantly less for the diets containing poultry fat at all levels than for the control diet. In the case of corn oil only the 10% level significantly reduced HI plus HA/GE intake. Values for the poultry fat were slightly lower than for the corn oil. Level or source of fat had no effect on its ME value as determined by the total excreta collection method.