Effects of a Non-Fasting Moulting Treatment and Extended Cold Storage on Some Egg Quality Traits of a Commercial White Laying Hen.

This study was aimed at investigating the effects of non-fasting moulting treatment and extended cold storage on table egg quality traits of a commercial white layer hen. For this research, 360 eggs were collected from moulted and non-moulted flock four weeks after the end of the moulting program. The hens in each group were allowed ad libitum access to water and their respective diets as grain barley for the moulting group and standard layer feed for the control group during the moulting period of 10 days and then a complete layer ration after the moulting program through the laying period. Sample eggs of each of these two groups were numbered, weighed and further assigned to a different storage period as daily fresh eggs: 15, 30, 45, 60 and 75 days. All eggs were stored between 4°C and 5°C and 55% and 60% relative humidity throughout the experiment. Egg weight, egg length, egg width, shell strength, shell weight, shell thickness, yolk height, yolk diameter, yolk colour, albumen height, albumen width, and albumen length were measured at each consecutive analysis period for egg quality comparison. Non-fast moulting treatment significantly affected egg weight, egg-width, egg length and breaking strength (P < 0.001, P < 0.001, P < 0.001 and P < 0.020). There were no significant effects of the length of a cold storage period on the external quality traits of egg weight, egg width, egg length and egg-shape index. Shell thickness and breaking strength of eggs were affected significantly (P < 0.001 and P < 0.02) by the length of a storage period. The yolk height and yolk colour scores were found to be significantly greater in eggs from the moulting group while all internal quality characteristics were significantly affected by the length of a storage period (P < 0.001). In conclusion, even if it was cold storage, egg quality tended to decline in the extended storage period and non-fasting moulting treatment improved the external and internal egg quality. [ABSTRACT FROM AUTHOR]