Choice Preference Of Laying Chicks For Different Types Of Music And The Effect Of Timeliness Of Music

With the deepening of scientific research and the development of intensive breeding mode,music is gradually regarded as a good way to enrich the environment and has a positive impact on animal welfare.However,currently,music is mostly focused on improving animal health and welfare in rats,mice,and pigs,while research on the health and welfare of laying hens is not indepth enough.This study focuses on the effects of music stimulation on the behavior response,physiological indicators,and expression of emotion related genes in the hypothalamus of laying hens,with Roman white laying hens as the experimental subjects.This provides a theoretical basis for utilizing music enriched environments to improve the welfare level of laying hens.Experiment 1: Although music can have a positive impact on animals,there is currently no consensus on whether animals have preference for music types.This study determined the choice preference of laying hens for different music types through the Conditional Position Preference(CPP)experiment.Play four different types of music(classical music,jazz,rock music,and Chinese folk music)simultaneously and separately in four soundproof rooms in the testing room,observe and record the number of visits and duration of stay of individual laying chicks in the four music rooms.A total of 30 Romanian white laying chicks participated in the experiment,and each chick was officially tested for 10 minutes.The results showed that the number of visits of laying chicks in the classical music soundproof room was significantly higher than that of jazz(p<0.05),rock music(p<0.05),and Chinese folk music(p<0.001).The residence time of chicks in classical music soundproofing rooms was also significantly longer than that of jazz(p<0.05),rock music(p<0.05),and Chinese folk music(p<0.001).Therefore,classical music is a relatively preferred music genre for chicks,while jazz,rock music,and Chinese folk music are relatively preferred music genres for chicks.Experiment 2: The aim is to explore the behavior responses of laying chicks to short term stimuli of four different types of music.In this experiment,24 Romanian white laying chicks were randomly selected and divided into 4 groups(classical music group,jazz music group,rock music group,and Chinese folk music group),each raised in 4 chicken cages.Each group randomly grabs one laying chick and places it in the corresponding music compartment.Four different types of music are played separately for 3 hours in each of the four soundproof compartments.After the end of music stimulation,three behavior tests(novel object test,tonic immobility,and open field test)were conducted on laying chicks to detect their anxiety and fear levels.The results showed that there was no significant difference(p>0.05)in the response to event behavior(jumping,spreading wings,pecking,and modifying)and state behavior(walking,standing,lying down,and perching)among the four music groups of chicks.In the novel object test,there was no significant difference in the incubation time of pecking among the four music groups of chicks(p>0.05),but the classical music group had the least incubation time overall.There was no significant difference in the duration of tension immobility among the four music groups in the tonic immobility(p>0.05).In the open field test,there was no significant difference in the number of squares crossed by the four music groups of chicks(p>0.05);However,the incubation period for the first movement of chicks in the classical,jazz,and rock music groups was significantly higher than that in the Chinese folk music group(p<0.05),with the classical music group having the shortest incubation period;The exploration time of the classical music group’s chicks was significantly higher than that of the Chinese folk music group(p<0.05),but there was no significant difference compared to the jazz and rock groups(p>0.05).Therefore,classical music relatively alleviates the anxiety of laying hens in open field test and to some extent promotes the expression of their activity behavior.Classical music may be more beneficial for improving the welfare of laying hens.Experiment 3: Raising laying chicks in a classical music enriched environment until transfer,observing the behavioral responses of chicks as the music stimulation time prolongs,and detecting changes in physiological indicators and expression of emotion related genes in the hypothalamus.Using Roman white laying hens as experimental animals.360 1-day old chicks were purchased from commercial chicken farms and randomly divided into three groups(control group C,low decibel music group LM,and high decibel music group HM).Starting from 1-day old,the LM group and HM group chicks received music stimuli of 65-75 d B and 85-95 d B,respectively.Group C had no external music stimuli except for background sound,and the experiment lasted until 16 weeks old.At the 1st,2nd,4th,8th,and 16 th week of age,behavioral responses(running,walking,sitting alert,sitting still,standing still,standing alert,exploring,gathering,flying)of chicks were recorded,and hypothalamic emotion related genes(stress-related genes,serotonin genes,and Neurotrophic and cognitive genes)and physiological indicators were detected.The results showed that:(1)Low decibel music significantly increased the exploratory behavior of chicks at weeks 2 and 4(p<0.05);At weeks 1 and 2,high decibel music significantly increased the aggregation behavior of chicks(p<0.05);In the first week,high decibel music significantly increased the wingspan flight behavior of chicks(p<0.05);High decibel music significantly increased the running behavior of chicks in the first and second weeks(p<0.05);Low decibel music significantly increased the walking behavior of chicks in the first week(p<0.05);At the first and second weeks,high decibel music significantly increased the sitting immobility behavior of chicks(p<0.05);At weeks 1,4,8,and 16,high decibel music significantly increased the sitting alertness behavior of chicks(p<0.05);At weeks 1 and 2,low decibel and high decibel music significantly increased the standing immobility behavior of chicks(p<0.05);At weeks 1,2,and 16,high decibel music significantly increased the standing alertness behavior of chicks(p<0.05).Therefore,music stimulation in the early stages of life significantly increases the expression of egg chick activity behavior,and the effect of high decibel music is even stronger.As the stimulation time of music prolongs and the age of laying hens increases,the role of music gradually manifests in the static and alert behavior of laying hens.(2)The expression of stress-related genes AVP,CRH,NR3C2,and POMC was significantly increased in the hypothalamic tissue of high decibel music group chicks at weeks 1,2,4,and 8,respectively(p<0.05);High decibel music stimulation also significantly increased the relative expression levels of serotonin gene NGF,HTR2 C,and HTR7 at weeks 2,8,and 16,respectively(p<0.05);Moreover,the HTR1 B,ADAM10,and NTRK1 genes in the high decibel music group were significantly higher than those in the control group at weeks 4 and 8(p<0.05).(3)Low decibel music stimulation significantly increased the concentrations of serotonin(5-HT),dopamine(DA),IL-1β,and IL-12 at weeks 1,4,and 16(p<0.05).At week 2,low decibel music stimulation significantly increased the concentrations of IL-6,IL-8,IL-10,and IL-12(p<0.05).At week 8,low decibel music stimulation significantly increased the concentrations of IL-1β,IL-2,IL-4,and 5-HT(p<0.05),and at weeks 14 and 16,the concentration of cortisol(CORT)in the low decibel music group was significantly lower than that in the control group(p<0.05);High decibel music stimulation significantly increased the concentrations of IL-8,IL-10,and DA at weeks 1,2(p<0.05),as well as the concentrations of 5-HT,IL-1β,IL-2,and IL-4 at weeks 4,8(p<0.05).At week 16,high decibel music stimulation significantly increased the concentrations of IL-6 and IL-10(p<0.05),and the concentrations of cortisol(CORT)in the high decibel music group chicks at weeks 1,2,and 8 were significantly lower than those in the control group(p<0.05).There was no significant difference in the concentrations of IFN-γ,TNF-α,Ig G and Ig A(p>0.05).Conclusion: Laying chicks have a relative preference for classical music;Music,as a way of enriching the environment,can promote the behavioral expression of laying chicks in the early stages of life,making it more diverse,especially the expression of activity behaviors(such as decoration,standing,walking,jumping,perching behavior,spreading wings,etc.).The results of behavior tests(novel object test,tonic immobility,and open field test)indicate that music can to some extent reduce the anxiety level of laying chicks.Under the long-term stimulation of music,the negative behavior of laying chicks(such as sitting alert,standing alert,etc.)decreases with time.Combined with changes in hypothalamic emotion related genes and physiological indicators,it indicates that the impact of music on laying chicks is mainly concentrated in the early stage of music stimulation,and the impact of high decibel music is more obvious.