Amino Acid Digestibility of Full-Fat Canola Seed, Solvent-Extracted, and Expeller-Derived Canola Meals in Broiler Chickens and Pigs

The objective of this study was to compare the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and amino acids (AA) in full-fat canola seed (FFCS), solvent-extracted canola meal (SECM), and expeller-derived canola meal (EXCM) for broiler chickens with those for pigs. Three semi-purified diets were prepared to contain FFCS, SECM, or EXCM as a sole source of nitrogen. A nitrogen-free diet was also formulated to estimate the basal ileal endogenous losses of CP and AA. A total of 272 male broiler chickens (initial BW = 932 ± 80.6 g; 21 d post-hatching) were allotted to 4 experimental diets in a randomized complete block design with BW as a blocking factor. Birds had free access to experimental diets for 5 d, and ileal digesta samples were collected after birds were euthanized by sodium pentobarbital. Sixteen barrows (initial BW = 18.8 ± 0.75 kg) surgically fitted with T-cannula at the distal ileum were divided into 4 blocks based on BW and assigned to experimental diets for 2 consecutive periods. In each experimental period, ileal digesta samples were collected during 2 d of collection periods. A 2 × 3 factorial treatment arrangement was applied to determine the effect of species (broiler chickens or pigs) and 3 feed ingredients (FFCS, SECM, or EXCM). Pairwise comparison among digestibility of CP and AA in feed ingredients were conducted within species. There were interactions (P < 0.05) between species and feed ingredients in digestibility of indispensable AA except for Lys. In broiler chickens, the AID of most of indispensable AA in FFCS were greater (P < 0.05) than those in SECM, but were not different from those in EXCM. In pigs, however, the AID of most of indispensable AA in EXCM were greater (P < 0.05) than those in FFCS, but were not different from those in SECM. The SID of Arg, His, Leu, and Thr in broiler chickens fed FFCS were greater (P < 0.05) than SECM, but were not different from EXCM. In pigs, the SID of Arg, His, Ile, Leu, Phe, Thr, and Val in EXCM were greater (P < 0.05) than those in FFCS, but were not different from those in SECM. The SID of Arg, Ile, Leu, Lys, Met, Phe, Trp, and Val in broiler chickens were greater (P < 0.05) than those in pigs. In conclusion, species differences in digestibility of AA exist among canola seed products.