Effects Of Plumage Condition On Production,Blood Biochemistry And Gene Expression Of Layers At Different Stocking Density

Feather status and stocking density are increasingly being concerned as an indicator of animal welfare.A total of 210 54-week-old brown-shelled hens with different feather status were selected from the large group.After the feather status score,the feather status score was higher and the feather status score was lower.On this basis,each group was divided into 3 groups.3/Cage and 4/cage are divided into 4 groups with 3 replicates in each group and 5 single cages per replicate.The effects of feather status at different feeding densities on the mortality rate,blood biochemical parameters,partial immune-related gene expression,behavior and production performance of laying hens(54-61 weeks old)were studied.The results are as follows:1.The effect of feather condition and stocking density on the death rate of laying hens.During the test,2 hens with poor feather status died 1.1.9%(2/105),and all hens with good feathers survived;3/cage and 4/cage each died 1 Only,the death rate was 1.1%(1/90)and 0.83%(1/120).2.The effect of feather condition and stocking density on blood biochemical parameters of laying hens.The serum GSH-Px,T-AOC and TG levels of the laying hens were significantly higher than those of the lower feather status scores(P<0.05),while the serum MDA and ALP levels were significantly lower than the lower feather status scores.(P<0.05).The T-AOC content of the 4/cage laying hens was significantly lower than that of the 3/cage laying hens(P<0.05),and the two were in GSH-Px,MDA,ALP,Cort,TG,T-CH and Glu.There were no significant differences in the indicators(P>0.05).3.The effect of feather status on stress and immune-related gene expression in laying hens.The mRNA expression of HTR2C gene in the neck of the group with higher feather status score was significantly lower than that of the lower feather status score(P<0.05),and the expression of iNOS gene in the tissue was not significantly different.The mRNA expression of chicken IL2 gene in liver and chest muscle was significantly lower than that in feather group(P<0.05).The expression of TLR4 mRNA in the spleen of the group with higher feather status score was significantly higher than that of the lower feather status score(P<0.05).4.The effect of feather condition and stocking density on the behavior of laying hens.The performance index of laying hens with good feathers was significantly higher than that of feathers(P<0.05).Although the feeding index was also higher than that of feathers,the difference was not significant(P>0.05);the feathers were in poor condition.The chickens in the standing and combing index were significantly higher than those in the feathers(P<0.05).The walking and staring index was higher than that of the feathers,but the difference was not significant(P>0.05).Feeding density had no significant effect on the behavior of laying hens.5.The effect of feather condition and stocking density on laying performance of laying hens.The average daily feed intake and feed-to-egg ratio of the laying hens were significantly lower than those with lower feather status scores(P<0.05),while the average egg weight was significantly higher than the lower feather status scores(P<0.05).).The daily egg production rate and daily average feed intake of the 4 cages/caged laying hens were higher than those of the 3/cage group(P<0.05),while the ratio of eggs to eggs was significantly lower than 3 chickens/caged hens(P<0.05).).6.The effect of feather condition on egg quality.The egg shape index and egg yellow color of the higher feather status scores were significantly lower than those with lower feather status scores(P<0.05),while the eggshell strength was significantly higher than the lower feather status scores(P<0.05).Feeding density had no significant effect on egg quality.Conclusion:The high density of feeding can reduce the health status of laying hens;the poor feather condition can lead to the increase of abnormal behavior of laying hens;the performance of laying hens with good feathers is better than that of laying hens with poor feathers.