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Abstract Expeller-pressed canola meal (ECM) is a co-product obtained from expeller-pressing canola seeds to obtain canola oil, and it has potential as a cost-effective feedstuff in swine diets. Also, ECM may be a superior protein source compared with solvent-extracted canola meal due to its greater digestible amino acid (AA) contents. However, limited information is available on the effects of enzyme supplementation on AA digestibility in ECM for pigs. Therefore, the objective of this study was to determine the effects of multi-carbohydrase (MC) and protease supplementation on the apparent (AID) and standardized ileal digestibility (SID) of AA in ECM when fed to growing pigs. A total of 12 barrows (65.9 ± 5.0 kg initial body weight), each fitted with a T-cannula in the distal ileum, were allocated for 2 studies: the current study (4 treatments) and another study with 8 treatments. Pigs were arranged in a 12 × 6 incomplete Latin square design with 12 diets and 6 periods, resulting in 6 observations per dietary treatment. Four dietary treatments were: 1) basal ECM diet; 2) ECM diet with MC supplementation (1 kg/tonne); 3) ECM diet with protease supplementation (250 g/tonne); and 4) ECM diet with both MC and protease supplementation. A casein diet was fed to all 12 pigs for 1 wk after feeding experimental treatments to quantify endogenous losses of AA. All diets contained 0.3% titanium dioxide as an indigestible marker. Pigs were fed 1 of the 4 diets during each of the 7-d periods, and ileal digesta were collected on d 6 and 7 from 0800 to 1700 h. Pigs were fed the diets at 2.8 times maintenance energy requirement based on their body weight at the beginning of each period. Data were analyzed using the PROC MIXED of SAS. The statistical model included MC, protease, and their interaction as fixed effects, and replication, animal within replication, and period within replication as random effects. Protease supplementation did not affect AID or SID of AA in ECM. Similarly, no significant differences were observed in MC supplementation on AID and SID of AA, except for a significant increase (P 0.05) in the AID of Gly with MC supplementation compared with the non-supplemented diet. No interactive effects were found between MC and protease supplementation on the AID and SID of AA in growing pigs. In conclusion, the digestibility of AA in ECM fed to growing pigs with and without enzyme supplementation did not differ, and no interactive effects were observed. Future studies will aim to investigate the dose-effect to accurately determine whether the absence of an effect was attributable to improper enzyme-to-substrate ratio.
Lee et al. (Sun,) studied this question.