| This thesis aims to study the influence of yeast selenium on production performance,egg quality and storage stability for hens with puffed flaseed feed,and to clarify the simultaneous enrichment effect of selenium and ω-3 polyunsaturated fatty acids(PUFA).On this basis,we also explored the protective effect of selenium on the storage stability of co-3 PUFA enriched eggs.This thesis mainly includes the following two parts.The purpose of the first experiment was to study the influence of yeast selenium on production performance and egg quality for hens with puffed flaxseed feed.In this part,540 hailan brown hens in peak period were selected,and were randomly divided into 6 groups with 6 replicates and 15 chickens for each replicate.Different concentration of selenium of 0,0.3,0.6,0.9,1.2 and 1.5 mg/kg were added to each group,which contains base feed and 15%puffed flaxseed.The whole experiment period were 14 weeks including pre-feed period(2 weeks)and experiment period(12 weeks).Results are as follows:(1)There was no significant influence of yeast selenium on production performance and egg quality for hens with puffed flaxseed feed(P>0.05).(2)Compared to blank group,the concentration of GSH-Px in liver increased significantly(P<0.001),and the concentration of SOS in liver increased first and then decreased with increasing level of selenium;the concentration of MDA degraded significantly when the level of selenium changed between 0.3-0.6 mg/kg(P<0.05);(3)the concentration of selenium increased with the increasing level of selenium in feed(P<0.05),and total concentration of selenium were 18.50,45.06,74.96,93.61,117.55,135.53 μg/100 g in each group.(4)Selenium had no significantly influence on SFA,MUFA,PUFA,ω-6 PUFA and ω-3 PUFA in ω-3 PUFA enriched eggs(P>0.05),In conclusion,antioxidant capacity of liver could be improved with the addition of yeast selenium(0.6 mg/kg)in puffed flaxseed feed;the concentration of selenium increased significantly with the increasing of level of yeast selenium,and the level of yeast selenium addition had no significant effect on egg yolk fatty acids,selenium and ω-3 PUFA could be concentrated in eggs at the same time.The purpose of the second experiment is to study the effects of selenium,storage temperature and storage time on the stability of co-3 PUFA enriched eggs.72 non-damaged eggs were collected from groups in the first experiment with selenium of 0.3 mg/kg and Se 0.6 mg/kg,respectively.Each group were divided into two parts and stored under 4℃ and 25℃,respectively.Two eggs were selected to detect related index under 20,30 and 40 days.Results are as follows:(1)Selenium had no significant effect on the quality of co-3 PUFA enriched eggs at different storage temperatures(P<0.05).Related index could not be detected due to egg white were hydrated under 25℃.Besides,temperature had a significant effect on egg quality(P<0.05);(2)the concentration of MDA in egg yolk were significantly higher under 4℃ compared with 25℃;the MDA concentration with 0.6 mg/kg selenium was a little bit lower than eggs with 0.3 mg/kg selenium(P>0.05).(3)The storage temperature has no significant effect on the selenium concentration in egg yolk,egg white and whole egg(P>0.05).(4)Storage temperature had no significant effect on the fatty acid in egg yolk(P>0.05).When stored for 30 and 40 days,the content of ω-3 PUFA in egg yolk with selenium of 0.6 was significantly higher than eggs with selenium of 0.3 mg/kg(P<0.05).There is no interaction of temperature.In summary,egg quality reduced significantly and MDA content increased in egg yolk under 25℃ storage conditions;ω-3 PUFA content with selenium of 0.6 mg/kg was significantly higher than eggs with selenium of 0.3 mg/kg when stored for 30 to 40 days;and storage temperature had no significant effect on selenium concentration.In conclusion,adding yeast selenium(0.6 mg/kg)to the flaxseed diet could improve the liver antioxidant capacity and the concentration of selenium in eggs,besides it had certain protection effect on the fatty acids in ω-3 PUFA enriched eggs.Egg quality and MDA were mainly affected by temperature changes during storage period. |
