Acta Vet. Brno 2008, 77: 561-568
Feeding Fish Oil and Linseed Oil to Laying Hens to Increase the n-3 PUFA in Egg Yolk
The research was carried out to assess the possibility of egg yolk enrichment with n-3 PUFA through supplementation of fish oil (FO) and linseed oil (LO) to layer diet. A total of 84 ISA Brown laying hens were divided into three groups. Each group consisted of seven cages with four hens per cage. Groups received diets differing in combinations of oils. The diet fed to group E1 contained 1.50% LO and 3.5% FO, group E2 had diets with 2.5% LO and 2.5% FO, and group E3 was fed diets with 3.5% LO and 1.5% FO. Contents of fatty acids in oils, diets and egg yolks were analyzed. The egg yolk content of α-linolenic acid (α-LNA) and omega-3 polyunsaturated fatty acids (n-3 PUFA) in total fatty acids was increased (P < 0.001) due to the increased content of linseed oil in hen diet and it was the most favourable in group E3. In groups E1, E2 and E3, the α-LNA content was 3.25%, 4.33% and 5.18%, respectively, and the n-3 PUFA content was 6.80%, 7.22% and 8.50%, respectively. The content of eicosapentaenoic acid was higher (P < 0.05) in egg yolks of group E1 than that of groups E2 and E3. No significant differences (P > 0.05) were found among groups in the docosahexaenoic acid content. The omega-6/omega-3 PUFA ratio in groups E1, E2 and E3 was 2.96, 2.93 and 2.49, respectively. Increased concentration of linseed oil and reduced concentration of rapeseed oil in diets resulted in less SFA (P < 0.001) and more n-3 PUFA in egg yolks. It was determined that laying hens have the ability to synthesize EPA and DHA from α-LNA if they receive enough α-LNA through their diets.
