عنوان مقاله [English]
نویسندگان [English]چکیده [English]
This experiment was carried out to study the effects of different levels of canola meal of different fat sources on the egg quality, performance as well egg yolk cholesterol during the first 12 weeks of age in laying hens (Hy-line W-36). Throughout the experiment a total of 432 hens were employed in a completely randomized design in a factorial arrangement of 3×4, with three levels of canola meal (0, 7.5 and 15%) and different fat sources (soybean oil, canola oil, poultry tallow and fatty acid), with three replicates (n=12). The results showed that Egg weight (g), egg production (%), egg mass (g), feed consumption (g), feed conversion ratio, and egg quality traits including, egg gravity, shell weight (g), haugh unit, shell thickness (mm) and egg yolk cholesterol were not significantly affected by levels of canola meal and by fat sources. The egg production was increased by addition of soybean oil to diets containing 15% canola meal (p<0.05). Feeding of 15% canola meal + soybean oil, increased egg production (p<0.05). Layers which consumed canola oil bore a higher yolk index. Feed cost per kilogram of egg mass decreased significantly in the treatment of 15% canola meal, and poultry fat. The replacement of 15% canola meal and poultry tallow supplementation as a fat source in diets should be useful in decreasing of feed costs.