Effects of Dietary Supplementation of Nano-Selenium on the Egg Selenium Content and Egg Production Rate of North China Hens

This study determined the effect of dietary supplementation with nano-selenium on the egg selenium levels and egg production rate of North China laying hens. Healthy 60-week-old hens (160 hens) were randomly divided into four experimental groups and fed a basal diet supplemented with nano-selenium at differing levels: 0.0 mg/kg (control group), 0.3 mg/kg (low-dose group), 0.6 mg/kg (medium-dose group) and 1.2 mg/kg (high-dose group). The experimental diets were fed for 28 d and daily egg production was recorded. Eggs were collected every seven days for determination of egg white, egg yolk and total egg selenium using hydride generation-atomic fluorescence spectrometry. The egg production of the medium-and high-dose groups on day 7 was significantly higher than that of the control and low-dose groups (P < 0.05). The egg white selenium level of the high-dose group on day 21 was significantly higher than that of the control group (P < 0.05). The egg yolk selenium level of the low-dose group was significantly higher than that of the control group (P < 0.05). The total egg selenium level of the high-dose group on day 21 was significantly higher than those of the control and medium-dose groups (P < 0.05). Dietary supplementation of nano-selenium significantly increased egg white, egg yolk and total egg levels of selenium, as well as daily egg production. The largest increase in egg selenium level was observed in the high-dose group on day 21.