Effects Of Fresh Lemon On Performance And Egg Products Of Laying Hens In Late Laying Stage

In this study,540 Jingfen layers aged 79 weeks were added fresh lemon,citric acid and yellow meterin to their diets to compare the effects of fresh lemon,citric acid and yellow meterin on the performance,egg quality and blood biochemical indexes of laying hens.In the early stage of the experiment,the egg production rate and the feed / egg ratio in the fresh lemon group were significantly lower than those in the control group(P<0.05),but there was no significant difference in the feed intake(P>0.05)and the average egg weight in the fresh lemon group(4%).The color of egg yolk was significantly lower than that of the control group(P<0.05)and the serum levels of CK HDP70 HDL TG T-CH ALP in the fresh lemon group and citric acid group were significantly lower than those in the control group and the flavomycin group(P<0.05).The content of MDA GSH-Px SOD in the serum of the fresh lemon group and citric acid group was significantly higher than that of the control group(P<0.05).The antibody level of H5 in 4% fresh lemon group was the highest.In the middle stage of the experiment,the egg laying rate of citric acid group was significantly higher than that of other test groups(P<0.05),the broken egg rate of citric acid group and 4% fresh lemon group was significantly lower than that of the other three groups(P<0.05),and the feed / egg ratio of citric acid group was the lowest.The average egg weight of 4% fresh lemon group was significantly lower than that of the other test groups(P<0.05).The eggshell strength of the fresh lemon group and citric acid group was significantly lower than that of the other three groups(P<0.05).There was no significant difference in protein height and eggshell strength among the three groups(P>0.05).In the later period of the experiment,2%,4% fresh lemon group had no significant difference between the control group and the control group.The broken egg rate was significantly higher than the other three groups(P<0.05);4% fresh lemon group had the lowest average egg weight,and the yellow color of citric acid group was significantly higher than the control group(P<0.05);4% fresh lemon group and citric acid group were GSH-Px,SOD content was significantly higher than the other three groups(P<0.05),the level of H5 antibody in the 4% fresh lemon group was the highest,and the ND antibody level in the Yellow mycin group was the highest(P<0.05).In conclusion,fresh lemon as a feed additive in the late laying stage can effectively reduce the rate of egg production,increase the egg protein height and freshness,as well as alleviate heat stress and improve the antioxidant ability of the hens.It is better to add 4% fresh lemon.