Effect of genotype and housing system on the concentration of cholesterol in egg yolk

Abstract

The objective of the study was to assess the concentration of egg yolk cholesterol in Czech Hen and Oravka breeds kept in two different breeding systems (cages and litter). Egg-yield, hen day egg production and feed mixtures consumption were observed during the experimental period. The eggs for laboratory analysis were collected during 4-week periods, at 34, 38, 42, 46 and 50 weeks of age of the laying hens. Sample extracts were analyzed by gas chromatography employing mass selective detector. Only daily consumption of feed mixtures was significantly affected by genotype, housing systems and their interaction. The cholesterol concentration was significantly affected by genotype and housing system of laying hens. The highest average concentration of cholesterol in egg yolk was determined on litter (Oravka 11.64 mg/g and Czech Hen 10.84 mg/g) compared to cages. Simultaneously, the influences of age of laying hens and its interaction with the housing system were also demonstrated. The highest concentration of cholesterol was measured at 34 weeks of age of hens bred on litter. Conversely, the lowest concentration was found at 42 weeks of age of hens housed in cages. Other parameters were inconclusive. The results showed that the selection of a suitable genotype and housing system can significantly affect the concentration of cholesterol in egg yolk.