Study On Growth Of Beak And Effects Of Antipecking Eye Mask And Beak Trimming On Production Performance Of Chicken

Beak is considered as the tool for feeding,protection and preening of chicken.The growth and development of beak are affected by many factors such as genetics,environment and feeding management.Beak-related behaviors such as feather pecking and anal pecking are related to birds’ health,production performance and welfare.In this paper,the growth and development of chicken beak,and the transcriptome of upper beak of Wannan three yellow chichen were studied.The effects of anti-pecking eye mask and beak trimming on production performance,beak length,and behavior of native chicken were investigated.The molecular mechanism of infrared beak trimming on growth and development in chicken was explored by RNA-seq technology.(1)The growth and development of beak in Wannan three yellow chichen were studied.The upper beak of Wannan three yellow chichen increased with age,the absolute growth per day was largest from 1 to 21 d,and the average upper beak length was 17.25 mm at112 d old.Von Bertalanffy model was more suitable for fitting the growth curve of upper beak length.There was a very significant correlation between upper beak length and body weight of Wannan three yellow chichen.(2)The transcriptomics of beak length in chicken was studied.The differences of transcriptome of six birds with long beak and short beak were analysed by RNA-seq technique in Wannan three yellow chichen.A total of 766 differentially expressed genes(DEGs)were obtained,631 DEGs were up-regulated and 135 DEGs were down regulated in birds with short beak.The differentially expressed genes are mainly involved in mucin type O-glycan biosynthesis,amino sugar and nucleotide sugar metabolism,fructose and mannose metabolism,among them ALX1 and WIF1 gene may play an important role in the regulations of chicken beak length.(3)The effects of anti-pecking eye mask on the production performance,beak length and behavior in Wannan three yellow chichen were stduied.Three hundred and sixty63-d-old Wannan three yellow chickens with intact beaks were randomly allocated into 3groups.Birds were fitted with the anti-pecking eye mask at 63 d(PAD63d)and at 77 d of age(PAD77d).Control birds were not fitted with anti-pecking eye mask.There were no significant effects of anti-pecking eye mask on body weight,carcass traits and meat quality(P>0.05).The mortality in the PAD63 d and PAD77 d groups were lower than that in the control group.Compared with those in the PAD77 d and control group,the feed conversion ratio from 63 to 112 d of age was lower in the PAD63 d group.The average daily feed intake of birds from 63 to 112 d of age was lowest in birds in the PAD63 d group,intermediate in birds in the PAD77 d group,and highest in control birds(P<0.05).Birds in the PAD63 d and PAD77 d groups showed a lower frequency of walking/running,a higher frequency of sleeping,and higher plumage scores of the back and tail than those of control birds(P<0.05).Birds’ daily walking steps in the PAD77 d group decreased compared with that of birds in the control group(P<0.05).The upper beak length at 91 d and 112 d of age was longest in birds in the PAD63 d group and shortest in control birds(P<0.05).(4)The effects of infrared beak treatment on production performance,beak length and behavior were investigated in Wannan three yellow chichen.Two hundred and forty1-day-old Wannan three yellow chickens were randomly allocated into 2 groups(the infrared beak treatment(IRBT)group and control group).Birds in the IRBT group had lower body weight at 7 and 14 d,average daily feed intake from 22 to 28 d,and the feed conversion ratio from 57 to 112 d compared to the control group(P<0.05).Birds in the IRBT group had shorter upper beak lengths from 21 to 112 d of age(P<0.05),and the behavior of pecking other birds at 4 weeks of age decreased(P<0.05).Birds in the IRBT group had better plumage conditions of their backs and tails at 112 d of age than those of the backs and tails of birds in the control group(P<0.05).(5)The effects of beak trimming on production performance,beak length and behavior were investigated in 817 broiler breed.A total of 648 1-d-old birds were randomly allocated into 3 treatments: infrared beak trimming(IRBT),hot-blade beak trimming(HBBT)and no trimming(NBT).The body weight from 7 to 35 d in the IRBT group was significantly lower than that in the NBT group,and the body weight from 7 to 49 d was lower than that in the HBBT group(P<0.05).Compared to NBT group,birds in the IRBT group had lower average daily feed intake from 15 to 21 d,and higher heart percentage and L* value in the breast muscle.The upper beak length at 28 and 49 d of age were longest in NBT group,intermediate in birds in the HBBT group,and shortest in the IRBT groups(P<0.05).No evidence was found that HBBT caused changes in performance,behavior,carcass traits,organ percentages and meat quality except for lower change in spleen percentage.(6)The transcriptomics of liver in chicken by infrared beak trimming by was studied.RNA-seq technique was used to analyse the transcriptome of the livers in 817 broiler breed at 7 d of age.The results showed that 632 differentially expressed genes were screened,289 genes were up-regulated and 343 genes were down regulated in the IRBT group.The genes including ADH6,CYP11A1,CHRM3,SLC15A1,FBP2,FABP2,PCK1,MGAM,THRSP,CETP,PPP1R3 G,ADIPOQ,ACACB,ABHD6,CCK were involved in the regulation of feed digestion and absorption.FGF13 and FOS genes were related to growth development,PTCHD1 gene was related to behavior regulation,CCL4,CCR8,CCL19,STAT1 and SOCS3 genes were involved in immunity system.