تاثير ويتامين E و منبع آلي و معدني سلنيوم بركيفيت تخم مرغ در مرغهاي تحت تنش گرمايي

The Effect of Vitamin E, Organic and Inorganic Sources of Selenium on Egg Quality of Heat Stressed Laying Hens

This study was carried out to evaluate the effects of dietary vitamin E and organic and inorganic sources of selenium on egg qualitative characteristics of heat stressed laying hens. One hundred forty-four Hy-Line W-36 hens were divided into two houses with different environmental temperatures (24 and 33 °C). Dietary treatments had included additional amounts of selenium and vitamin E supplements. Experiment was a 2^3><2 factorial arrangement which was conducted as completely randomized design with 12 treatments and 3 replicates. Hen performance traits including egg production, egg weight, feed consumption and feed conversion ratio and egg quality characteristics including shell thickness, shell resistance, shell weight, albumen quality (Hough unit score) and yolk weight was measured during the experiment. Feed consumption, egg production and egg weight in hens exposed to high temperature was significantly lower than hens from the normal temperature group (P< 0 05). Exposure of hens to high temperatures also resulted in a significant decrease in egg quality. Egg weight, shell thickness, and Hough unit score were all significantly decreased when the hens were exposed to heat stress. Selenium supplementation to diet had a significant (P<0.05) effect on yolk colour.