Laying hens’ diet modification with flaxseed and fish oils to enrich egg yolks with omega-3 fatty acids and vitamin D3

Today, food enrichment is one of the most widely used methods in benefiting the food processing industry. The effects of four different dietary groups [basic diet (I), basic diet+flaxseed oil (II), basic diet+non-absorbable fiber+flaxseed oil (III)& basic diet+non-absorbable fiber+fish oil (IV)] were studied on the development of eggs with high content of long-chain omega-3 fatty acids &vitamin D3. To achieve this goal, the egg yolk oil was extracted by the cold extraction method and analyzed by gas chromatography. A total of 24 fatty acid compounds were identified in egg yolk oil, which ~48-52% of contained monounsaturated fatty acids (mainly oleic acid). The diet modifications significantly (p<0.05) increased the total content of egg yolk omega-3 fatty acids, and the highest value was observed in the diet (III) (84.2% increase compared to the control). The highest elevations were observed in ALA (3.49%), DPA (0.24%), and DHA (1.21%) fatty acids. Also, the ratio of ω-6/ω-3 fatty acids was ~18.36% in the control group (I), while in the diets II, III, and IV, the ratios decreased to ~3.79 (~80%), ~3.16 (~83%), and ~6.09 (~67%), respectively. Overall, the results indicated that diet (III) & (IV) were the most effective to increase the content of omega-3 fatty acids and Vit-D3 in egg yolk, respectively.