effect of different levels of linseed and safflower seed on modifying yolk fatty acids content and antibody titter of laying hens

one-hundred-sixty-eight 28-wk-old hy-line layers (w-36) were used to evaluate the effect of different levels of linseed (ls) and safflower seed (ss) on antibody titter, blood and yolk cholesterol, yolk fatty acid content and the ratio of omega-6/ omega-3. hens were randomly assaigned in a compeletly randomised design each 3 replicates of 8 hens. they were fed diets contained 0, 4, 7 and 10% ls or ss for 12 wks. as a result, antibody titter, mean yolk and blood cholesterol content were not affected by dietary treatments. dietary linseed or safflower seed did not significantly affect saturated fatty acids (meristat, palemitat and stearat), ω-7 (palemitoleat) and ω-9 (oleat), arachidonat and long chain omega-3 polyunsaturated fatty acids (eicosapentanoeic and docosahexaenoic acid) in egg yolk. the linoleic acid in yolk was reduced when ls was included in diet, whereas they were significantly increased when fed diets contained ss. the yolk linolenic acid was increased linearly as the level of ls increased from 0 to 10%, but not affected by ss treatment. although yolk ω -6/ ω -3 ratio content increased to 21.87 when 10% ss diet was fed, but it reduced from 1.86 in those fed 10% ls diet. it seems that inclusion of ss and ls in laying hen dits can increase the polyunsaturated fatty acid; however, the inclusion ls in laying hen dits increase and decrease the yolk sum of ω -3 fatty acids and the yolk ratio of ω -6/ ω -3 respectively.