The effects of housing systems and age of hens on the weight and cholesterol concentration of the egg

Abstract

The effects of laying hen age and the housing of laying hens in conventional cages, enriched cages, litter system and outdoor system on egg weight and yolk and egg cholesterol concentration were studied. ISA brown laying hens were used in the experiment. The characteristics were measured at 39, 50, 59, 68 and 75 weeks of age. Fifteen eggs were always collected from each housing system. In total, 300 eggs were analyzed. There were not any significantly different results in the eggs from the hens living in the different housing systems or from the age of laying hens on the weight of eggs. But the housing system and the age of hens had a significant (<i>P</i> &le; 0.01) effect on both yolk and egg cholesterol concentration. The concentration of yolk and egg cholesterol was the lowest (<i>P</i> &le; 0.01) in the enriched cages (12.5 mg/g yolk and 211.2 mg/egg) and the highest in the litter technology (14.1 mg/g yolk and 242.6 mg/egg). Further, there was a significant (<i>P</i> &le; 0.01) influence of the interaction between the housing system and the age of hens on egg weight and on yolk and egg cholesterol concentration.