EFFECT OF DIETARY ω-3, ω -6 AND ω -9 FATTY ACIDS ON PRODUCTIVE AND PHYSIOLOGICAL TRAITS OF LAYING HENS

SUMMARY his study investigated the effect of various sources and levels of vegetable oil as a source of omega-3, omega-6 and omega-9 fatty acids on productive performance, egg quality, fatty acids profile and some physiological traits of laying hens. Two hundred and seventy Bovens laying hens at 45 weeks of age were randomly divided equally into nine treatments resulting from factorial design (3×3); three sources of vegetable oil (soybean, sunflower and linseed oil) with three levels (1, 1.5 and 2%). Obtained results showed that, final body weight, hen-day egg production percentage, feed consumption, egg quality characteristics, plasma total protein, globulin, aspartate transaminase, alanine aminotransferase, total lipids and very low density lipoprotein concentrations were not significantly affected (P>0.05) by various sources or levels of vegetable oils. The use of linseed oil in laying hens' diets led to a significant increase (p≤0.05) in the egg mass and weight of eggs produced from those hens. Feed conversion ratio of laying hens fed either linseed or sunflower oil diets were significantly (P≤0.05) improved compared to those received dietary soybean oil. There was a significant increase in the level of MUFAsin the egg yolk occurred as a result of using sunflower or linseed oil, compared to soybean oil. The inclusion of sunflower oil in the layer diets was able to improve significantly (P≤0.01) the concentration of γ-linolenic (C18:3n6) and arachidonic (C20:4n6) fatty acids in the egg yolk. The use of different levels of sunflower or linseed oil up to 2% led to a significant (P≤0.01) improvement in the level of high density lipoprotein. Moreover, layer fed diet with different levels of linseed oil significantly (P≤0.01) had the lowest concentration of low density lipoprotein. Significant (P≤0.01) improvement in the level of antioxidants was observed for the groups fed on diet containing linseed oil, followed by those fed dietary sunflower oil, compared to the control group that fed on soybean oil. In conclusion, the use of both sunflower oil or linseed oil up to 2% in the diet of laying hens are able to improve egg production, egg quality, the level of essential fatty acids in egg yolk, in addition improving the level of antioxidants and blood biochemical parameters.