In a completely randomized design with 3*3 factorial arrangements and 4 replicates, 432 day-old Cobb male broiler chickens were used to evaluate the replacement of soybean meal with local grown rapeseed meal in the diet of broiler chickens with or without a dietary NSP degrading enzyme. The rapeseed meal was replaced with soybean meal at the levels of 0 (control), 15 and 30 percent for 6 weeks. The enzyme levels added to the diets were 0 (control), 0.025% and 0.050%. Feed intake, body weight gain and feed conversion ratio were adversely affected by added levels of rapeseed meal during the starter (0-21 d), grower (21-42 d) and overall feeding periods (P<0.0001). Adding 0.025% enzyme significantly (0.004) improved body weight gain at starter period. The interactions between rapeseed and enzyme for body weight gain were significant in all periods (P<0.001). Feed conversion ratio was not significantly affected by adding enzyme into the diets. Added levels of rapeseed meal significantly increased the weights of liver, proventriculus, gizzard (P<0.0001) and abdominal fat pad (P<0.028). Adding levels of rapeseed meal were also significantly increased the concentration of serum triiodothyronine (T ) at 42 days of age (P<0.002) while adding enzyme 3 into the diets had no significant effect among treatments . Therefore under the conditions of this study, use of lower levels of rapeseed meal might be more practical in broiler diets. For higher levels of replacement, further investigations are required.

Keywords