This experiment was conducted to consider of replacing soybean meal (SBM) with canola meal (CM) on productive performance and egg quality of laying hens from 28 to 36 weeks of age. A total of 180 Hy-Line W-36 laying hens were distributed into 6 treatments, 5 replicates and 6 hens in each. The experiment was a completely randomized design arranged factorially 3×2 with 3 levels of canola meal: 0, 7.29, and 14.59% (canola meal replaced 0, 20 and 40%, respectively, of protein from soybean meal; soybean meal was 27.41, 22.63 and 17.84%, respectively) and 2 levels of protease (0 or 200 g/ton; 75000 PROT/g; Ronozyme® ProAct). Six iso-energetic and iso-nitrogenous diets were formulated on digestible amino acid basis. Feed intake (FI), egg production (EP), egg weight (EW), egg mass (EM) and feed conversion ratio (FCR) were evaluated in this study. Shape index, Haugh units, egg shell thickness, shell weight and yolk color were measured at 36 weeks of age. Statistical analysis was conducted using an analysis of variance (ANOVA) followed by the Duncan multiple test (P<0.05). No interactions were found between canola meal and protease supplementation for any traits studied. For the entire experimental period, FI, EW, EP, EM and FCR were not affected by canola meal or protease supplementation (P>0.05). Haugh unit significantly decreased (P<0.05) at 20 and 40% substitution of CM in the diet (81.7 and 80.1; respectively) than control (87.7). Protease supplementation increased egg shape index (76.6 vs. 75.3%) and egg shell thickness (0.562 vs. 0.552 mm; P=0.058). In conclusion, canola meal can be used with a substituting ratio of 40% of the crude protein contributed by SBM in laying hen diets without any negative effect on bird performance. Egg quality was not affected by canola meal inclusion in the diet except for Haugh unit that was decreased. However, protease supplementation improved some egg traits.
