LAUSR

Abstract The aim of the study was to evaluate the effect of different levels of dietary hybrid rye on eggs laid by Isa Brown laying hens and their quality, such as physical parameters, nutritional value (basic chemical composition, cholesterol content, fatty acid profile) as well as safety (microbiological purity). A total of 72 Isa Brown hens aged 26 weeks were allocated to 3 groups fed with 0%, 15% and 25% levels of hybrid rye in their diet up to week 50. At week 50, 72 eggs per group were collected for analysis. The 25% rye level had no significant effect on most of the examined physical parameters; however, a tendency to heavier eggs in this group was noted. An increased rye level resulted in lighter yolks with a lowered share of redness and yellowness compared to those obtained from hens fed a control diet. The administration of 25% of rye in the diet influenced the basic chemical composition of the yolks by increasing the water content and reducing the fat content, but with no significant effect on the contents of ash, chlorides and cholesterol. The sum of saturated fatty acids in yolks decreased along with the increase in dietary rye level while the sum of mono- and polyunsaturated fatty acids increased. Moreover, a lowered ratio of ω-6: ω-3 fatty acids was found with dietary rye level increases.