The effect of vitamin C on egg shell quality under high environmental temperatures.

Abstract

For a month 24 pullets 7 months old were kept in 2 rooms at 65 degrees to 70 degrees F and relative humidity 50 to 60% and were given a layer's mash with 2.75% Ca. The temperature of one room was then reduced to 55 degrees . For 6 months that of the other was raised to 85 degrees and the humidity to 75 to 80% for 2 months then reduced to the original conditions for 2.5 months and raised again for the rest of the experimental period. Ascorbic acid was given for the last 2 months. Sp. gr. of eggs and shell deformation, breaking strength and percentage shell, but not thickness, tended to fall throughout the trial. Heat stress significantly reduced all aspects of shell quality. In the cold room ascorbic acid did not significantly affect shell quality. In the hot room it increased sp. gr., weight and percentage shell but not shell thickness, breaking strength or deformation. In the cold room plasma Ca did not change significantly. High temperature and humidity significantly reduced plasma Ca, and ascorbic acid in the hot room raised it.-G. F. H. (Abstract retrieved from CAB Abstracts by CABI’s permission)