عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The present study was carried out to investigate the replacement of soybean meal by different levels of canola meal (either with or without canola meal undergoing heat processing). Two hundred forty commercial layer hens (LSL strain) at 54th week of age, selected based on the same egg production percentage and body weight. The experimental design was a CRD, in a factorial arrangement of 4 replicates. The factors included were 3 levels of canola meal replacements (33, 66 and 100%) and 3 types of canola meal namely: 1. without processing; 2. dry heat processing (80°C for 30min); 3. autoclaving (120°C with 15lb pressure per inch for 30min). A control diet based on corn and soybean meal was included. The experiment was carried out for three 58 days periods. Feed intake, egg production percentage, egg weight, egg mass, feed conversion ratio, Haugh Unit, yolk color, egg specific gravity, shell percentage, shell thickness , pancreas and liver relative weight, body weight gain, T3 and T4 hormones as well as alkaline phosphatas concentration of plasma were recorded. The results indicated that feed intake, egg weight, egg mass, FCR, Haugh Unit, egg specific gravidity, shell thickness, T3 and T4 hormones and alkaline phosphatase concentration, weren't affected by either canola meal and heat processing or the interaction between canola meal and heat processing. Egg production percentage, pancreas relative weight and yolk color were affected by different levels of canola meal (P<0.05). Liver relative weight was affected by heat processing of canola meal (P<0.05). Eggshell percentage was affected by heat processing and as well as canola meal interaction (P<0.01).