Research On Animal Production

Extended Abstract
Introduction and Objective: Egg is a complete food for feeding different age groups, which has a wide range of required nutrients, contains chemical compounds sensitive to adverse environmental factors such as temperature, shelf life and storage conditions. In the present experiment, the duration, location and storage status of edible eggs in home refrigerators and their effects on quality traits, shell traits and biochemical characteristics of egg yolks were evaluated. 
Material and Methods: In this experiment, 216 healthy eggs produced one day of hens of W36 line strains, aged 77 weeks, were prepared and in the form of 2 * 3 * 3 factorial arrangement, including 3 weeks, 3 floors and two egg storage conditions (sharp to Bottom or vice versa) in 18 treatments, 72 replications and 3 eggs per replication were used in a completely randomized design. 
Results: Duration of storage, location and storage of eggs in the refrigerator had significant effects on internal quality, shell traits and biochemical parameters of egg yolks (p<0.05). Storage of eggs in the upper floors of the refrigerator compared to the lower floor increased the yolk index and yolk color (p<0.05). With increasing the storage time of eggs to three weeks in the refrigerator, the percentage of yolk, units, egg shell thickness and yolk cholesterol concentration decreased, while the percentage of white and yolk color increased (p<0.05). Egg storage conditions in the refrigerator (bottom sharp or vice versa) did not have significant effects on internal quality, shell traits and biochemical characteristics of egg yolks (p<0.05). 
Conclusion: Due to the nutritional value of various compounds and the nature of some nutrients in eggs and especially egg yolks (such as unsaturated fatty acids), as a concern for nutritionists and housewives, duration, location and the storage status of the eggs in the refrigerator is imortant. In the present experiment, it was observed that, firstly, the lower floor of the refrigerator is not a suitable place for storing eggs, and secondly, by increasing the the duration of keeping eggs to more than two weeks, the internal quality, the quality of the shell and the yolk content of the eggs will decrease, but the storage condition of eddible eggs in the refrigerator (sharp egg point down or vice versa) had no significant effects on the aforementioned traits. According to the above findings, it is recommended, that the eggs needed by households not to be purchased in large quantities and not to be stored for more than 2 weeks, as well as in the lower floors of home refrigerators.