Changes in egg quality during storage depending on the housing system
Housing systems for laying hens affect not only the performance of the hens but also the quality of eggs and are likely to affect their storage. The aim of study was to evaluate changes in the quality of eggs from enriched cages and from free range during 21 days of storage. The eggs to determinate of technological value were collected between the 20th and 60th week of hen age at the 28 day interval. Egg weight, qualitative indicators of albumen and yolk were monitored in fresh eggs and eggs stored 2, 7, 14 and 21 days. The eggs were stored at a room temperature 20 – 22°C and relative humidity 55-60 %. In total 900 eggs were analyzed, of which 150 eggs were one housing system per collection and 30 eggs per storage day. The egg weight of fresh eggs from enriched cage was 61.5 g and from free range 61.0 g. The egg weight during the 21 days of storage significantly decrease in both housing systems (P≤0.001), by 2.29g in cages and by 3.69g in free range (P≤0.001). The Haugh units (HU) were influenced by interaction of housing system and storage time (P≤0.001). Significantly higher HU in fresh eggs were found in eggs from cages (89.2 HU) compared to free range (79.1 HU) but in eggs from cage was faster decline in quality than in eggs from free range. These changes also confirmed differences in the increase of albumen pH. Changes during storage were also noted in yolk quality. In both housing system was yolk shaped index in fresh eggs 44.9% and significant interaction of housing system and storage time (P≤0.021) showed a faster decline in free range (by 17.7%) compared to cage (by 16.9%). The yolks were lighter during storage with lighter color in free range than in cages (P≤0.001). From the results is clear that the housing system influenced also storage of egg, when the greater deterioration of albumen quality was in eggs from enriched cage while the yolk from free range.
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