Effects Of Dietary Supplementation Of Selenium Yeast And Selenium-rich Herbage On Performance Of Laying Hens

The objective of experiment was to study the effects of dietary selenium yeast and selenium-enriched herbages on performance,health status and selenium deposition in eggs of laying hens.The experimental results were supported the development of selenium-rich egg industry in Selenium-rich area of Kaiyang.The experiment 1:Effects of dietary yeast selenium on performance of laying HensThe total of 108 healthy and 162-day-old hyline brown laying hens with similar body weight were selected and divided randomly into four groups,each group with 3replicates,there were 9 laying hens in each replicate.The control group was fed basal diet（There is no selenium in the premix）,Treatment groupsⅠ,ⅡandⅢwere added respectively with selenium yeast of 0.3 mg,0.6 mg and 0.9 mg selenium yeast per kilogram of the diet.The pre-experiment lasted for 10 days,formal period lasted for60 days.Feed intake,total egg production and egg weight were recorded daily in repetitions during the formal period.The laying hens were weighed on 0 d and 60^thd of the experiment to calculate performance.Egg samples were collected on the 30^thand 60^th days,the egg quality and antioxidant index of yolk.The sample of egg,plasma and liver samples were collected on the 60^th d of formal period to determine selenium content in egg and plasma,antioxidant and immune indexes in plasma,and antioxidant indexes in liver.（1）Impact on production performance:There were no significant differences in daily feed intake（ADFI）,laying rate,feed to egg ratio（F/E）and weight gain of laying hens in each group（P>0.05）.The average egg weight of treatment groupⅢwas significantly higher than that of treatment groupⅡ（P<0.05）.（2）Effect on egg quality:The eggshell thickness in treatmentⅠ,ⅡandⅢgroups was significantly higher than that in control group（P<0.05）.The haugh unit of treatment groupⅢwas significantly higher than that of control group and treatment groupⅠ（P<0.05）.There were no significant differences in egg shape index,eggshell strength,egg weight,albumen height and yolk color among all groups（P>0.05）.（3）Influence of anti-oxidation index:1)Compared to the control group,The total antioxidant capacity（T-AOC）of liver in treatment groupⅠwas significantly increased（P<0.05）,Malondialdehyde（MDA）content remained unchanged（P>0.05）.Compared to the control group,The activity of superoxide dismutase（SOD）in treatment groupⅢwas significantly increased（P<0.05）,There were no significant changes in total antioxidant capacity（T-AOC）and glutathione catalase（GSH-PX）activities（P>0.05）,Malondialdehyde（MDA）content remained unchanged（P>0.05）.2)The plasma total antioxidant capacity（T-AOC）,superoxide dismutase（SOD）and glutathione catalase（GSH-Px）in treatment groupsⅠ,ⅡandⅢwere significantly higher than those in control group（P<0.05）.There was no significant difference in malondialdehyde（MDA）content among all groups（P>0.05）.3)The experiment lasted for 30days,There was no significant effect on antioxidant index of yolk among all groups;The experiment lasted for 60 days,The content of malondialdehyde（MDA）in treatmentⅠandⅡwas significantly higher than that in control group and treatment groupⅢ（P<0.05）.（4）Influence on immune index:Compared to the control group,Immunoglobulin G（Ig G）in treatment groupⅡwas significantly decreased（P<0.05）,The immunoglobulin M（Ig M）in treatment groupⅡandⅢwas significantly decreased（P<0.05）,There were no significant differences in tumor necrosis factor（TNF-a）and interleukin-6（IL-6）among all groups（P>0.05）.（5）Influence on selenium content in egg and plasma:Selenium content in eggs increased significantly with the dietary selenium yeast supplemental level increasing（P<0.05）,The selenium content in eggs is respectively:0.221±0.064 mg/kg、0.512±0.088 mg/kg、0.723±0.084mg/kg、0.977±0.115 mg/kg.The plasma selenium content in treatment groupⅢwas significantly higher than that in treatment groupⅠand control group（P<0.05）.Different levels of selenium yeast were added in the diet,Selenium deposition in eggs can meet the requirements of selenium content in selenium-rich eggs,The deposition of selenium increased significantly with the increase of supplemental level,the performance,egg quality,antioxidant capacity and immunity of laying hens were improved with increase dietary selenium.The experiment 2:Effects of Selenium-enriched herbage on production performance of Laying HensThe total of 108 healthy and 162-day-old hyline brown laying hens with similar body weight were selected and divided randomly into four groups,each group with 3replicates,there were 9 laying hens in each replicate.The control group was fed a basal diet（There is no selenium in the premix）,Treatment groupsⅠ,ⅡandⅢwere fed basal diet supplemented with 5%,8%and 11%chicory（Se:2.31 mg/kg）,Treatment groupsⅣ,ⅤandⅥwere supplemented with 5%,8%and 11%alfalfa on the basis of basic diet（Se:2.45 mg/kg）.The sample collecion was the same as the experiment 1.（1）Impact on production performance:compare with the control group,There were no significant differences in average egg weight（AEW）,laying rate and weight gain of laying hens among all groups（P>0.05）,Average daily feed intake（ADFI）in treatment groupⅢwas significantly increased（P<0.05）,the feed/egg ratio（F/E）of treatment groupⅣwas significantly increased（P<0.05）.（2）Effect on egg quality:compare with the control group,The experiment lasted for 30 days,The protein height of treatment groupsⅠandⅣwas significantly increased（P<0.05）.The experiment lasted for 60 days,compare with the control group,The eggshell thickness in groupsⅠ、Ⅲ、Ⅳ、ⅤandⅥwas significantly increased（P<0.05）,The histone height and Haugh unit of treatmentⅣdecreased significantly（P<0.05）,The yolk color of treatment groupⅡwas significantly decreased（P<0.05）.（3）Influence of anti-oxidation index:1)Compare with the control group,The total antioxidant capacity（T-AOC）and superoxide dismutase（SOD）activity of liver in all treatment groups were not significantly affected（P<0.05）,The content of malondialdehyde（MDA）was significantly increased（P<0.05）,Glutathione catalase（GSH-Px）activity was significantly decreased（P<0.05）.2)Compare with the control group,There was no significant difference in plasma malondialdehyde（MDA）content among all groups（P>0.05）,The activities of total antioxidant capacity（T-AOC）,superoxide dismutase（SOD）and glutathione catalase（GSH-Px）in treatment groupⅠwere significantly increased（P<0.05）,The total antioxidant capacity（T-AOC）and superoxide dismutase（SOD）activity in treatment groupⅡwere significantly increased（P<0.05）,The activities of superoxide dismutase（SOD）and glutathione catalase（GSH-Px）in treatment groupsⅢandⅥwere significantly increased（P<0.05）,The activity of superoxide dismutase（SOD）in treatment groupsⅣandⅤwas significantly increased（P<0.05）.3)The experiment lasted for 30 days,compare with the control group,The superoxide dismutase（SOD）activity and total antioxidant capacity（T-AOC）of yolk in treatment groupⅠwere significantly decreased（P<0.05）;The superoxide dismutase（SOD）activity and total antioxidant capacity（T-AOC）of yolk in treatment groupⅡwere significantly decreased（P<0.05）and malondialdehyde（MDA）content was significantly increased（P<0.05）;The total antioxidant capacity（T-AOC）in treatment groupsⅢ、ⅣandⅤwas significantly decreased（P<0.05）,and malondialdehyde（MDA）content was significantly increased（P<0.05）;Treatment groupⅥsignificantly increased the content of malondialdehyde（MDA）.The experiment lasted for 60 days,compare with the control group,The superoxide dismutase（SOD）activity and malondialdehyde（MDA）content in treatment groupsⅠandⅥwere significantly increased（P<0.05）,The malondialdehyde（MDA）content in treatment groupsⅡ、Ⅲ、ⅤandⅥwas significantly increased（P<0.05）.（4）Influence on immune index:compare with the control group,The immunoglobulin A（Ig A）in treatment groupⅢwas significantly decreased（P<0.05）,Immunoglobulin G（Ig G）and immunoglobulin M（Ig M）were decreased in all groups（P<0.05）.（5）Influence on selenium content in egg and plasma:The plasma selenium content in treatment groupⅡwas significantly higher than that in treatment groupⅤ（P<0.05）.The selenium content in eggs of control group and treatment groupsⅠ、Ⅲ、Ⅲ、Ⅳ、ⅤandⅥwere respectively 0.221±0.064 mg/kg、0.222±0.064 mg/kg、0.225±0.081 mg/kg、0.266±0.058 mg/kg、0.201±0.066 mg/kg、0.228±0.077 mg/kg、0.187±0.044 mg/kg,The selenium content in eggs of groupⅢwas significantly higher than that of groupⅥ（P<0.05）,There were no significant differences among other groups（P>0.05）.Dietary supplementation of selenium-rich herbage had no effect on performance and selenium deposition in eggs of laying hens,However,the supplementation of selenium-rich herbage could improve antioxidant function and egg quality of laying hens,and both control group and the supplementation of selenium-rich herbage could meet the production needs of selenium-rich eggs.Adding different levels of selenium yeast in the diets of laying hens can meet the production requirements of se-enriched eggs.The deposition of selenium in eggs increased significantly with increasing of selenium yeast supplementation.Moreover,egg quality,antioxidant capacity and immunity were improved with increasing the dietary Selenium.Supplementation of selenium-rich herbage had no significant effect on production performance and selenium deposition in eggs of laying hens,but supplementation of selenium-rich herbage could improve antioxidant function and egg quality of laying hens.