Standardized Ileal Digestibility of Amino Acids in Canola Meal Fed to Gestating and Lactating Sows1

An experiment was conducted to determine the standardized ileal digestibility (SID) of CP and AA in solvent extracted canola meal (CM) fed to gestating and lactating sows without or with a multi-enzyme complex. Eight sows cannulated on day 40 of gestation were randomly assigned to 1 of 4 dietary treatments in a replicated 4 × 4 Latin square design. The 4 diets included 2 cornstarch-based diets with 31.3% CM as the only source of AA, without or with a multi-enzyme complex, a casein-cornstarch diet to determine ileal endogenous AA losses, and a phosphorus-free diet (phosphorus digestibility data reported elsewhere). All diets contained 0.3% titanium dioxide. Gestating sows were fed 3.0 kg/d of the respective experimental diets, whereas, during lactation, sows had ad libitum access to experimental diets. Ileal digesta samples were collected in midgestation, late gestation, and lactation. In each period, after 6-d acclimation to the experimental diets, on days 7 and 8, ileal digesta samples were collected continuously for 12 h. Results indicated that sows in lactation had greater apparent ileal digestibility (AID) of CP and all AA (P < 0.05) compared with sows in gestation. Enzyme supplementation improved (P < 0.05) the AID of histidine, lysine, methionine, valine, and alanine, and a tendency (P < 0.10) for improvement in AID was observed for arginine, isoleucine, tryptophan, and cysteine during lactation, but not during gestation. However, the SID of most AA was not affected by collection phase, but enzyme supplementation improved (P < 0.05) the SID of arginine, histidine, lysine, methionine, and valine during lactation. The SID of indispensable AA in CM fed to gestating and lactating sows were as follows: arginine, 89.2 and 91.3%; histidine, 93.1 and 94.0%; isoleucine, 85.9 and 87.0%; leucine, 89.2 and 89.2%; lysine, 87.0 and 87.7%; methionine, 92.2 and 93.2%; phenylalanine, 89.2 and 87.8%; threonine, 84.3 and 82.7%; tryptophan, 88.1 and 91.5%; valine, 85.9 and 84.3%. In conclusion, the SID of AA in CM fed to lactating sows may be improved if a mixture of carbohydrases is included in the diet, but under the conditions of this experiment, the carbohydrase mixture did not affect SID of AA in CM fed to gestating sows in midgestation or late gestation.