Impact of U.S. sorghum particle size on feed characteristics, growth performance, gizzard weight and pH in broiler chickens

Sorghum is a cereal grain that can serve as an energy source in broiler diets when it is competitively priced for feed formulation. The objective of this study was to evaluate U.S. sorghum particle size (mean geometric diameter, d gw ) effects on growth performance, gizzard weight, and pH in broilers from 4-49 d of age. A floor pen study was conducted with dietary treatments consisting of a corn-based ( C ; 800 µm) control diet and sorghum-based ( S ) diets with varying sorghum d gw (400, 600, 800, 1000, and 1200 µm). Body weight gain ( BWG ), feed intake ( FI ), and feed conversion ratio ( FCR ) adjusted for mortality were determined. On d 49, two birds of average body weight were selected from each pen for determination of gizzard pH and weight. Overall (d 4-49) birds fed sorghum-based diets had increased ( P < 0.05) BWG and FI compared to those fed the corn-based diets, resulting in no difference in FCR ( P > 0.05). Increasing sorghum particle size tended to increase FI (linear, P = 0.059) and BWG (quadratic, P = 0.056) of broilers, with the majority of the improvements in BWG occurring when sorghum particle size was ground to 1,200 µm. Increasing sorghum d gw up to 1000 µm increased relative gizzard weight (quadratic, P < 0.01). In conclusion, broilers fed the U.S. sorghum-based diets had increased BWG and FI compared to those fed the corn-based diets with no evidence of difference in FCR. Targeting a coarser particle size in the 1,000 to 1,200 µm range appeared favorable under these conditions for growth performance and gizzard development.