Effect of conjugated linoleic acid, high-oleic sunflower oil and fish oil dietary supplementation on laying hen egg quality

An experiment was performed to determine the effect of supplementing the diet of laying hens with conjugated linoleic acid (CLA), fish oil (FO) and high-oleic sunflower oil (HOSO) on hen performance, egg yolk fatty acid (FA) concentrations, and egg sensorial quality and firmness. Four treatments were factorially designed involving two levels of supplementation of FO (0 and 17 g kg-1) and HOSO (30 and 35 g kg-1) for diets containing 3 g kg-1 of CLA. A control diet was also designed, with 30 g kg-1 HOSO but with no CLA or FO. Twenty five 38 week-old Warren laying hens were randomly assigned to 28 d dietary treatments with the above diets, following a pre-experimental period of 21 d. The type of diet did not affect egg production characteristics. The addition of CLA increased the yolk fat concentrations of CLA, saturated FA and C22:5 n-3, but reduced those of monounsaturated FA and C20:4 n-6. Supplementation with FO increased long-chain n-3 FA concentrations but reduced those of long-chain n-6 FAs, t10,c12 and tt-CLA. Supplementation with HOSO had little influence on yolk fat composition. Supplementation with CLA and FO impaired egg sensorial quality in an additive fashion, although yolk firmness was not affected. Eggs from hens fed diets with 3 g CLA kg-1 and 30 g HOSO kg-1 —but no added FO — contained 9 g CLA kg-1 yolk fat and were of acceptable sensorial quality to trained panellists. However, no eggs double-enriched in CLA and n-3 FA were obtained that were also sensorially acceptable