modification of egg yolk fatty acids profile by using different oil sources

the study was conducted to evaluate the effects of different dietary oil sources supplementation on laying hens’ performance and fatty acids profile of egg yolks. seventy-two 23-week-old laying hens (tetra-sl) divided into six experimental diets (four replicates and three birds per replication) in a completely randomized design for nine weeks. experimental diets were included: 1) control (no oil), 2) 3.00% fish oil, 3) 3.00% olive oil, 4) 3.00% grape seed oil, 5) 3.00% canola oil, and 6) 3.00% soybean oil. the diets were similar in terms of energy and protein. egg production, egg mass, egg weight, feed intake, feed conversion ratio and fatty acid composition of egg yolk were determined at the end of the trial. the results indicated that the performance parameters were not significantly different between treatments in the entire period (p > 0.05). however, fatty acids profiles of yolk were affected by experimental diets (p < 0.05). fish oil significantly reduced omega-6 fatty acids and increased docosahexaenoic acid (dha) and eicosapentaenoic acid (epa) in egg yolk. also canola oil increased linolenic acid content in the egg yolk. in conclusion, fish oil increased omega-3 long-chain fatty acids and decreased omega-6 to omega-3 ratio in eggs which may have beneficial effects on human health.