Daily energy intake of broiler chickens is altered by proximate nutrient content and form of the diet.

An experiment was designed to test the ability of broiler chickens to equalize daily energy intake when proximate components of the diet were changed. A factorial arrangement was used to test effects of protein, fat, and fiber content in the diet. The simplest diet contained only corn and soybean meal to provide energy and protein. Protein contents were calculated to be 16.4, 18.2, and 20.0%, with added protein from a combination of corn gluten meal, fish meal, and peanut meal. Hydrolyzed fat was added at 0, 2.5, 5.0, and 7.5% of the diets. A combination of alfalfa meal, oats, and wheat middlings was used to increase the fiber of the corn soy diet by approximately 2 and 4%. The 36 combinations were fed as mash. In addition, 8 of the diets were fed as pellets. All diets were fed for 12 d from the time broilers reached approximately 1.2 kg. A total excreta collection was used to determine ME, and carcass analysis provided fat and energy content. When fed mash, only sex had a significant effect on grams of feed eaten per day. Sex and dietary fat content affected gain per day. Sex, fat, and fiber altered the kcal of ME eaten per day. Broilers fed 5% added fat ate approximately 10% more energy per day than those fed no added fat, and broilers fed 4% added fiber ate approximately 20% less ME than those fed no added fiber. A comparison of results from mash and pellets showed that only sex and form affected gain per day, feed per day, and kilocalories of ME eaten per day. For the mash and pellets, protein, fat, fiber, and several interactions affected the ME per gram; however, the ME per gram was similar for pellets and mash. The results suggest that the diet composition and form have a significant effect on the energy intake of broiler chickens.