220 Effects of using soybean meal, canola meal, and corn distillers dried grains with solubles on net energy, greenhouse gas emission, and nitrogen balance in group-housed pigs

The objective was to test the null hypothesis that there are no differences in net energy (NE), greenhouse gas emission, and N balance in pigs fed diets containing soybean meal (SBM), canola meal (CM), and corn distillers dried grains with solubles (DDGS). Three dies contained corn and one of the three feed ingredients (i.e., SBM, CM, or DDGS). A total of 24 growing pigs (initial weight = 46.84 ± 2.25 kg) were allotted to 6 chambers with 4 pigs per chamber. The 6 chambers were then allotted to the three diets using a repeated 3 Í 3 Latin square design with 3 periods. Pigs had free access to water and feed. Feces and urine samples were quantitatively collected during the collection period, and O2 consumption, CO2 and CH4 productions, and urine N excretion were measured during collection and fasting periods. Using Proc MIXED of SAS, the statistical model included diet as fixed variable and square, chamber, and period as random variables. Pairwise comparisons were used to separate the means. Results indicated that the apparent total tract digestibility (ATTD) of dry matter and gross energy were greater (P < 0.05) in SBM diet compared with CM and DDGS diets (Table 1). Concentrations of NE were not different between DDGS and SBM diets, but were greater (P < 0.05) compared with the CM diet. Daily O2 consumption per kg gain was greater (P < 0.05) and CO2 production per kg gain tended to be greater (P < 0.10) in pigs fed the CM diet compared with pigs fed the SBM or DDGS diets. However, production of CH4 did not differ among the three diets. Intake of N and total N excretion were not different among pigs fed the three diets, but the ATTD of N and absorbed N were greater (P < 0.05) and retained N (g/d) tended to be greater (P < 0.10) for pigs fed the SBM diet compared with the CM or DDGS diets. Retention of N (% of intake) did not differ among the three diets. Retention of N (% of absorbed) was not different between SBM and CM diets or between CM and DDGS diets, but was less (P < 0.05) in the SBM diet than in the DDGS diet. In conclusion, use of SBM or DDGS increased NE in corn-based diets compared with CM fed to group-housed pigs. Per kg gain, pigs produced less greenhouse gas when fed SBM or DDGS diets than when fed the CM diet. Pigs fed the diet containing SBM had greater absorbed and retained N (g/d) compared with those fed diets containing CM or DDGS.