Effect Of Rosemary Extract On The Production Performance,Egg Quality And Antioxidant Performance In Laying Hens

The purpose of this experiment was to explore the effect of rosemary extract on the production performance,egg quality,and antioxidant properties of laying hens.690 laying hens at 23 week old with similar body weight were divided into 5 groups with 6 replicates(each replicated with 3 cocks and 20 hens).Group A was fed with a basal diet,and groups B,C,D,E were supplemented with 50 mg/kg,100 mg/kg,200mg/kg,400 mg/kg rosemary extract in the basal diet,respectively.The pre-test period was one week and the formal period were fourteen weeks.Before the end of the experiment,two eggs were randomly collected from each replicate for three consecutive days.At the end of the experiment,two laying hens were randomly sampled for blood collection by pterygoid vein from each replicate.The results were as follows:1)Production performance: Compared with the control group,50 mg/kg,200mg/kg,and 400 mg/kg rosemary extract groups could significantly reduce the ADFI of laying hens in the first period of the experiment(24-30 weeks)(P<0.05),100mg/kg rosemary extract group had a tendency to reduce the ADFI(0.05<P<0.1);200mg/kg,400 mg/kg rosemary extract groups could significantly reduce the ADFI of laying hens in the later period of the experiment(31-37 weeks)(P<0.05),In the whole period of feeding(24-37 weeks),200 mg/kg and 400 mg/kg rosemary extract groups could significantly reduced ADFI of laying hens(P<0.01).The mean egg production rate,mean egg weight,feed-to-egg ratio,deformed egg rate and dead panning rate had no significant different among the groups(P>0.05).2)Egg quality: Compared with the control group,100 mg/kg,200 mg/kg,and400 mg/kg rosemary extract groups could significantly improve the egg color(P<0.01);400 mg/kg rosemary extract group could significantly increase the crude protein content in whole eggs(P<0.05).The eggshell strength,eggshell thickness,egg shape index,hastelloy unit,egg yolk relative weight,eggshell relative weight,total cholesterol,triglycerides,and crude fat had no significant different among the groups(P>0.05).3)Antioxidant indicators: The T-AOC activity of plasma in 100 mg/kg,200mg/kg rosemary extract groups were significantly higher than the control group(P<0.05);The GSH-Px activity of plasma in 100 mg/kg,200 mg/kg,and 400 mg/kg rosemary extract groups were significantly higher than the control group(P<0.01).The MDA content of plasma had a downward-trend in each test groups(0.05<P<0.1).The SOD and CAT activity of plasma had no significant different among the groups(P>0.05).4)Biochemical indicators: The GLU content of serum in 200 mg/kg,400mg/kg rosemary extract groups were significantly lower than the control group(P<0.05);The ALP content of serum in 100 mg/kg,200 mg/kg rosemary extracts groups were extremely significantly higher than the control group(P<0.01).The CREA content of serum in 100 mg/kg,200 mg/kg,and 400 mg/kg rosemary extract groups were significantly lower than the control group(P<0.01);The TP,ALT,AST,HLD-C,LDL-C,TG,TC,UREA content of serum had no significant different among the groups(P>0.05).In summary,rosemary extract can reduce the feed intake of laying hens,save feed,improve the quality of eggs and improve the body’s antioxidant performance.This study preliminarily conclude that rosemary extract has the potential value as a green feed additive for laying hens,and the recommended concentration in the feed for laying hens is 200-400 mg/kg.