Canola oil and vitamin A were evaluated for their effects on egg characteristics, egg cholesterol and egg triglycerides (TG) in laying hens prone to heat-stress during summer months. Four levels of canola oil (0, 2, 3 and 4% of diet) in combination with two levels of vitamin A (3,000 or 10,000 IU/kg of diet) were fed to laying hens for a period of 12 weeks. Various egg-quality parameters were measured on weekly basis while, serum TG, egg cholesterol and TG contents were analyzed during the last week of the trial. The results of the study showed that the egg weight, egg mass, yolk weight, Haugh unit score, shell thickness, shell weight and egg breaking-strength were similar (P>0.05) for all canola oil levels supplemented to the laying hens. Higher egg weight and egg mass (P<0.05) were noted for the hens at the diet with 10,000 IU vitamin A /kg of diet whereas, all other egg characteristics were not influenced by increasing the supplemental level of vitamin A. Serum TG, egg cholesterol and TG contents were not changed (P>0.05) by increasing canola oil or vitamin A levels in the diet of laying hens. It might be concluded from the results of the present study that canola oil as a source of omega-3 fatty acids can be included in the diet of laying hens without compromising the quality characteristics of the eggs.

Key words: Canola oil, Egg characteristics, Hens, Vitamin A