Enrichment Of N-3 Polyunsaturated Fatty Acid In Egg Yolk And Tissues And Its Effect On Lipid Metabolism In Laying Hens

This dissertation consists of eight experiments. A uniform design method was employed to study the n? polyunsaturated fatty acid enrichment in the egg yolk and tissues and its effect on lipid metabolism of laying hens by supplementing flaxseeds, fish oils, vitamin E (yE), and tea polyphenols (TP) in the diet. They are summarized as follows: Experiment 1. Effect of dietary n? polyunsaturated fatty acids on performance of laying hens. A uniform design, with four independent dietary factors such as the flaxseed, fish oil, VE and TP, was used to study the effect of dietary n? polyunsaturated fatty acids on performance. 1. Dietary level of fullat flaxseed no high than 10% had no adverse effect on the performance of laying hens. 2. When the dietary levels of flaxseed, fish oil, VE and TPwererespectively9.87%, 1.00%, 100mg/kg, 40g/t, the eggweight, laying rate can reach respectively 56. 72 grams/egg, 86. 31%. There figures were 1. 54% for egg weight, 9. 28% for egg production than the control group. 3. Dietary flaxseeds or ALA remarkably decreased abdominal lipid deposition ( P < 0.05)in laying hens. 4. Increasing of dietary tea polyphenols ( TP ) can lower hepar weight(P<0. 05).