Abstract: The aim of this experiment was to study the effect of different levels and sources of dietery selenium supplementation on laying hen’s production performance and egg quality. 648 hybrid and laying hens of Beijing You chicken and Lohmann-pink chicken with age in 23-week were randomly allocated into 12 groups according to experiment requirement to compare the effects of different doses of two sources of selenium on production performances and egg quality in laying hens for 8-week feeding in this study. Both selenium sources were added into the basal diet at 0.3, 1.0, 2.0, 3.0,4.0 and 5.0 mg/kg of selenium, and 1 to 6 groups were added with sodium selenite while 7 to 12 groups with selenium-enriched yeast. The results indicated that the selenium addition of less than 5.0 mg/kg tended to increase the laying rate(P＞0.05) and had no significant negative impacts on egg quality,whatever its sources. The selenium-enriched yeast had better effects than sodium selenite on production performances and egg quality in laying hens.The best selenium level in laying hen’s feed was separately 2.0 and 3.0 mg/kg in the form of sodium selenite and selenium-enriched yeast.The group of selenium-enriched yeast was significant higher than the group of sodium selenite on the average daily feed intake and the eggshell strength(P＜0.05),while the group of sodium selenite was significant higher than the group of selenium-enriched yeast on albumen height and haugh unit(P＜0.05).

Key words: selenium; laying hen; production performance; egg quality