INFLUENCE OF GRINDING, ROLLING, AND PELLETING ON THE NUTRITIONAL-VALUE OF GRAIN SORGHUMS AND YELLOW CORN FOR BROILERS

Two experiments were conducted to determine the effect of grain source, form, and pelleting on body weight gain and feed conversion of broilers. In Experiment 1, grain forms (finely ground or rolled) and sources: yellow corn (YC), low tannin (LTS) and high tannin (HTS) sorghums were evaluated in a 2 x 3 factorial arrangement. The YC, LTS, and HTS were incorporated in the diets on an equal weight basis. Experiment 2 involved a 2 x 4 factorial arrangement of feed form (mash or pelleted) and grain sources: YC plus 4.7% fat, LTS plus 6.4% fat, HTS plus 6.4% fat and HTS plus 9.3% fat. All diets were isocaloric and isonitrogenous. No interactions (P > .11) between grain sources and grain forms or between grain sources and feed forms were observed for weight gain and feed conversion in either experiment. Rolling grains decreased weight gain (P < .02) and feed conversion (P < .05), but pelleting the complete diets improved weight gain (P < .0001) and feed conversion (P < .0001) regardless of grain source. Weight gain and feed conversion of birds fed YC and LTS were not different (P > .27), but both were decreased (P < .05) in birds fed HTS. When extra energy was added from animal fat to the HTS diet (9.3%), weight gain (P < .04) and feed conversion (P < .003) were improved over the HTS diet with only 6.4% fat. Pelleting did not decrease assayable tannin in HTS. Results indicated that adequate grinding was needed for maximum utilization of the grain, and that pelleting improved the performance of broilers fed diets that were isocaloric and isonitrogenous.