Six expeller-extracted canola meal (ECM) samples produced under different seed conditioning temperatures (90, 95, or 100°C) and screw torques in the second press (low or high) were evaluated in a 3 × 2 factorial arrangement of treatments to determine the effect of processing on standardized ileal
amino acid digestibility (
SID) in 10 and 24-day-old broilers. A
nitrogen-free diet was fed to determine ileal endogenous
amino acid flow. Each diet was fed for 5 d to 6 replicate cages of 10 or 7 chicks, and ileal samples were collected
at 10 and 24 d, respectively. The endogenous flow (mg/kg DM intake) of CP and all
amino acids except Cys decreased (P < 0.01) with age. Conditioning temperature by screw torque interactions were detected (P < 0.05) for apparent ileal digestibility (AID) of
CP, Arg, Ile,
Lys, Phe, Thr,
Ala, Asp, Glu, Pro ,and Ser at d 10, and the same trend was observed at d 24 except for Ile,
Phe, Ala, and Pro (P > 0.05). Meals processed under medium conditioning temperature (95°C) at either low or high screw torque had the greatest (P < 0.05) AID of CP and total
amino acids. The
SID values followed a similar pattern as AID at both ages. When corrected for endogenous losses, the average AID of total
amino acids improved approximately 3.5 and 2.0 units,
at 10 and 24 d, respectively. The AID and
SID values increased (P < 0.05) with age for most AA, but the effect of age was not consistent between ECMs. A negative correlation was detected between NDF and neutral
detergent-insoluble
nitrogen (NDIN) content of the meals and
SID values of Lys at d 24 (r = -0.79, r = -0.76; P = 0.001, respectively). Processing conditions affected CP and
amino acid digestibility, likely because of alterations to the chemical composition of ECM and formation of indigestible complexes of
amino acids with fiber. The AID and
SID values increased with age independent of meal processing conditions.