Effect of sorghum distillers dried grains with solubles and microbial enzymes on metabolizable and net energy values of broiler diets

There is generally no information regarding the influence of distillers dried grains with solubles (DDGS) on the net energy (NE) value of broiler diets. It was hypothesized that the ME content of DDGS may overestimate its productive energy, leading to higher heat increment when used in broiler diets. Furthermore, it was of interest to investigate the potential benefits of a mixture of carbohydrases and protease on energy partitioning in diets containing DDGS. In this study, 2 evaluations, comparative slaughter (CS) or indirect calorimetry (IC), were conducted using the same batch of birds and feed. Two levels of DDGS (0 or 30%) without or with an enzyme mixture were used in a 2 x 2 factorial arrangement of treatments. The CS evaluation used 240 male Ross 308 broiler chicks with 6 replicates (10 birds each) per treatment from d 18 to 28. Carcass energy values were examined in 2 birds per replicate on each of d 18 and 28 to determine heat production (HP), NE, and ME. The IC evaluation used 32 birds acclimatized to 16 closed-circuit calorimeters (2 birds per chamber) following energy partitioning measurement by gaseous exchange and total excreta collection from 18 to 24 d. Birds fed DDGS had increased feed efficiency during starter and grower phases (P < 0.001). The CS showed no difference in HP between birds fed diets with or without DDGS. When measured by IC, birds fed diets containing DDGS had higher HP and lower NE (P < 0.01). Enzyme supplementation had no effect on HP, ME, or NE: ME ratio measured using CS or IC but increased NE and NE intake (P < 0.01) from d 18 to 28. Carcass fat retention was decreased (P < 0.05) and there was a lower NE (P < 0.01) in birds fed the DDGS-diets. This study showed that 30% dietary DDGS affects energy partitioning in broilers with more heat produced, decreased dietary NE, and less fat retained in the carcass.