Effect of feeding linseed oil and vitamin a on production performance, egg characteristics and egg yolk fatty acids in laying hens under sub-tropical conditions

In the present study, linseed oil and vitamin A were fed to the laying hens during hot summer months to produce n-3 PUFA-enriched eggs. Two hundred and forty White Leghorn hens were randomly divided into 24 replicates and fed diets, for 12 weeks,2 with 0, 2, 3, or 4% linseed oil in combination with 3000 or 10000 IU vitamin A/kg. The results revealed that the supplementation of linseed oil and vitamin A to the diets did not affect (P>0.05) the production performance and egg characteristics in laying hens. However, body weight and feed intake were decreased (P<0.05) with the increase in dietary linseed oil levels. The serum total cholesterol, triglycerides, blood glucose, egg cholesterol and triglycerides levels were similar (P>0.05) for all dietary treatment groups. However, serum HDL-cholesterol was increased while LDL-cholesterol was decreased in laying hens with the increase in dietary linseed oil supplementation. The total n-6 PUFA and n-6/n-3 PUFA ratio were decreased while the n-3 PUFA were increased linearly (P<0.001) in the egg-yolks by increasing dietary linseed oil level. Vitamin A did not influence (P>0.05) the egg-yolk fatty acid contents. It might be concluded that, the supplementation of linseed oil to the laying hens kept at high environmental temperature is beneficial for the production of n-3 PUFA-enriched eggs without any considerable effects on production performance.