Digestibility by growing pigs of amino acids in canola meal from North America and 00-rapeseed meal and 00-rapeseed expellers from Europe.

Abstract

The digestibility of CP and AA by growing pigs in coproducts from canola and 00-rapeseed may be influenced by the variety of seeds that was grown and the processing method used to extract the oil from the seeds. Therefore, the objective of this experiment was to determine the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of CP and AA in canola meal, 00-rapeseed meal, and 00-rapeseed expellers fed to growing pigs. Canola meal and 00-rapeseed meal are the coproducts produced after the residual oil has been solvent extracted from canola seeds and 00-rapeseeds, respectively, whereas 00-rapeseed expellers is the coproduct from 00-rapeseeds that have been only expeller pressed. Twenty-three barrows (initial BW: 28.8 ± 2.64 kg) that had a T-cannula installed in the distal ileum were allotted to a 9 × 23 Youden square design with 9 periods and 23 dietary treatments. The 23 diets included 7 diets based on the 7 samples of canola meal, 10 diets based on the 10 samples of 00-rapeseed meal, 5 diets based on the 5 samples of 00-rapeseed expellers, and a N-free diet. Each source of canola or rapeseed coproducts was used as the only source of CP and AA in 1 diet. The SID of CP and all AA except Val, Cys, and Glu were not different between canola meal and 00-rapeseed meal, but 00-rapeseed expellers had greater (P < 0.01) SID of CP and all AA except Thr, Trp, and Gly than 00-rapeseed meal, which possibly is due to heat damage in 00-rapeseed meal. For Lys, Met, Thr, and Trp, SID values of 70.6%, 84.5%, 73.0%, and 82.6%, and 71.9%, 84.6%, 72.6%, and 82.6% were obtained in canola meal and rapeseed meal, respectively, whereas values in 00-rapeseed expellers were 74.7%, 87.1%, 74.0%, and 83.4%. The SID for most AA was different (P < 0.05) among the 7 sources of canola meal, among the 10 sources of 00-rapeseed meal, and among the 5 sources of 00-rapeseed expellers. The concentration of standardized ileal digestible indispensable AA in canola and 00-rapeseed coproducts can be predicted from the concentration of the corresponding AA with only a low to moderate correlation (r(2) = 0.206 to 0.655). In conclusion, AA digestibility is not different between canola meal and 00-rapeseed meal, but 00-rapeseed expellers have greater digestibility of most AA than 00-rapeseed meal. Prediction equations may not always adequately estimate the concentration of indispensable AA and standardized ileal digestible indispensable AA in canola and 00-rapeseed coproducts.