Ileal amino acid digestibility in canola meals from yellow- and black-seeded Brassica napus and Brassica junceae fed to growing pigs

Twelve ileal cannulated pigs (30.9 ± 2.7 kg) were used to determine the apparent (AID) and standardized (SID) ileal digestibility of amino acids in canola meals derived from black(BNB) and yellow-seeded (BNY) Brassica napus canola and yellow-seeded Brassica juncea (BJY). The meals were produced using the conventional prepress solvent extraction process (regular meals) or a vacuum-assisted cold process of meal de-solventization (white flakes). Six cornstarch-based diets containing 35% canola meal as the sole source of protein in a 3 (variety) x 2 (processing) factorial arrangement and a 5% casein diet were randomly allotted to pigs in a 6 x 7 incomplete Latin square design to give 6 replicates per diet. The 5% casein diet was fed to estimate endogenous amino acid losses. There was an interaction effect (P < 0.05) of canola meal type and processing method on the SID of most amino acids. Among the white flakes, the SID of nitrogen, isoleucine, leucine, lysine, threonine, and valine were similar (P > 0.10) in BNY and BNB, but both had higher values (P < 0.05) than BJY. However, among the regular meals, the SID of lysine, methionine, threonine, and valine were higher (P < 0.05) in BJY followed by BNB and BNY. The SID of methionine (90.2%) was higher (P = 0.001) in BNY than in BNB and BJY. The results showed that the SID of nitrogen and amino acids in the meals from the canola varieties studied varied with processing method. Within the white flakes, amino acid digestibility values were similar in BNY and BNB, but both had higher digestibility than BJY. However, for canola processed using the regular method, BJY was similar to BNB in digestibility and both were superior to BNY.