| Popis: |
SUMMARY: This experiment determined the effects of yellow expeller-pressed canola meal (Y-EPCM) residual oil (10 vs. 14%), meal heat treatment (+H: at 115°C for 25 min vs. –H: no heat treatment), and dietary enzyme (no enzyme, lipase, protease, carbohydrase) on the nitrogen-corrected apparent metabolizable energy (AMEn) value and amino acid (AA) digestibility for broilers. In total, 480 male day-old chicks were assigned to 16 dietary treatments (6 birds per cage, 5 replicate cages per treatment) in a completely randomized design in a 2 × 2 × 4 factorial arrangement from day 14 to 21, where residual oil, heat treatment, and enzyme were the main factors. All 3 factors in the experiment interacted to affect the AMEn, in which meals with 14% residual oil supplemented with carbohydrase had higher (P < 0.05) AMEn 3,451 ± 112 kcal/kg compared to non-supplemented meal 2,823 ± 112 kcal/kg. The AA digestibility coefficients ranged from 99% for tyrosine to 44% for cysteine across treatments. The addition of lipase generally improved the standardized ileal AA digestibility of Y-EPCM by 0.5 to 2.5%, while heat treatment reduced the values (2–10%). The increased AA digestibility due to lipase might be as a result of an improvement in the accessibility of fat encapsulated protein to digestive enzymes which would not otherwise be accessible. In conclusion, heat treatment of Y-EPCM reduced its AMEn value and digestibility of some AA, implying that heat treatment had negative effects on nutrient digestibility. This negative effect of heat treatment could not be overcome with enzyme supplementation. |
