Effect of Pearl Millet Particle Size on the Performance of Broilers
Effect of feed particle size on the performance of broilers was studied. One hundred and sixty commercial broiler chicks were randomly distributed in four treatments with two replicates of twenty birds each. Ration containing 54 percent maize was used as control (T1) during starter phase (0 - 4 weeks) and 60 percent maize during finisher phase (4 - 6 weeks). The other rations were: T2- maize replaced with ground pearl (2 mm), T3- maize replaced with ground pearl millet (3mm), T4- maize replaced with pearl millet as such. Decrease in geometric mean diameter (GMD) and increase in surface area with the reduction of particle size were attributed to linear increase (P<0.05) in number of particles per gram. Geometric standard deviation (GSD) increased with large particles (3 mm) than those of small particles (2 mm). The relative proportions of coarse and medium particles decreased and that of fine particles within a sample increased linearly (P<0.05) with the decrease in pore size of the hammer mill screen. The modulus of fineness decreased (P<0.05) with the reduction in particle size. The body weight gains were highest and FCR was lowest on diets having particle size 1050μ and 966μ than those having particle size 762μ and 1261μ. Dry matter metabolizability was significantly (P<0.05) higher in treatments T2 and T3 compared to T1 and T4. Grinding of pearl millet improved (P<0.05) the nitrogen retention, which was higher than the rations based on maize. Significant (P<0.05) difference in gross energy metabolizability was observed in pearl millet based diet. Dressed yield, eviscerated yield, drawn yield, giblet yield, thigh muscle and breast muscle composition and weight (% live weight) of vital organs were similar among various treatments. It may be concluded that particle size of 1050- 1150μ of pearl millet based diet is optimum for broiler production.