Study On Effect Of Long-term Confinement On Behavior And MiRNA And Depression Related Protein Of Sow

Along with the increase of population,the traditional feeding pattern cannot meet people's growing demand for livestock products any longer.Therefore,the operators of animal husbandry turn to intensive production with high efficiency and space utilization,which is easy to manage.In China,most sows are bred in farrowing crates.This kind of breeding model has brought not only huge economic benefits to the pig industry,but also much damage to the health of the sows,which has greatly reduced the welfare level of the sows.In this study,the effect of long-term confinement on the behavior of sows was explored,as well as the regularity and internal association of stereotypic behaviors and mental illness based on the observation on sows' behaviors from the first fertilization to tertiparity and the detection of the concentrations of miRNAs and proteins in the brain of multiparous sows housed in crates and pens.Section 1: The effect of long-term confinement on the behavior of sowsSix primiparous Large Whites with similar weight,age and health condition were selected and transferred into farrowing crates after fertilization.All of them were transferred to delivery bed 4 days before the due date,and transferred to pens for fertilization after the weaning of piglets,after which these sows were moved to farrowing crates again.This process was repeated until tertiparity.The sow behavior was videotaped on the last three days of each month,and the duration of vacuum chewing,bar-biting,lying,standing,and sitting between 7:00-9:00 every morning was recorded.Through the comparative analysis of sows' behaviors in different parities,it was found that the vacuum chewing duration of secundiparous and tertiparous sows was significantly longer than primiparous sows(P <0.05),and through the comparative analysis of sows' behaviors in different gestation periods,we found the duration of primiparous sows' vacuum chewing during late gestation was significantly longer than that during early,middle gestation(P <0.05),and the duration of secundiparous sows' vacuum chewing during middle and late gestation was significantly longer than that during early gestation(P <0.05),while there was no significant difference between gestation periods(P >0.05).The duration of primiparous sows' standing during late gestation was significantly shorter than that during early gestation(P <0.05).The comparative analysis of sows' behaviors in gestation periods of parities showed that the vacuum chewing increased on the whole;the duration of vacuum chewing of primiparous sows during late gestation and secundiparous sows during early gestation was significantly longer than that during the initial,early,and middle gestation(P <0.05);the duration of sows' vacuum chewing during the middle and late gestation in secundiparity and early,middle and late gestation of tertiparity was remarkably longer than that during early,middle and late gestation of primipariry and early gestation of secundiparity(P <0.05);the duration of bar-biting decreased and then increased slowly on the whole,but there was no significant difference between the gestation periods of parities(P >0.05);the duration of lying increased and then decreased slowly,and there was no significant difference between gestation periods of parities(P >0.05);the duration of standing increased first and then increased,and which was remarkably shorter during late gestation of primipariry than initial and early gestation(P <0.05);the duration of sitting increased on the whole,which was significant longer during early,middle,and late gestation of secundiparity and tertiparity than that during initial gestation and early gestation of primipariry(P <0.05),and significant longer during middle and late gestation of tertiparity than late gestation of primipariry(P <0.05),and significant longer during early gestation of secundiparity and early,middle,and late gestation of tertiparity than middle gestation(P <0.05).Conclusion: Sows will produce certain adaptability to the living environment after entering farrowing crates,and the the duration of vacuum chewing and sitting will increase significantly,and after that the the duration vacuum chewing will remain at a certain level.Section 2: Effects of long-term confinement on the concentrations of miRNA and depression related proteins of sowsFour Large Whites in sixth parity were selected for this study,two of which were fed in farrowing crates and the others were fed in pens.The contents of miRNA in the ventral medial prefrontal cortex(vMPFC)and serum and depression related proteins in hippocampus were detected.The results showed that the contents of miR134 and miR1202 in vMPFC of sows in farrowing crates were remarkably higher than that in pens(P <0.01),and the contents of miR132 and miR335 of sows in farrowing crates were significantly higher than that in pens(P <0.05).The contents of dopamine transporter,brain-derived neurotrophic factor and metabotropic glutamate receptor 4 in hippocampus of sows fed in farrowing crates were significantly higher than that in pens(P <0.05).Conclusion: long-term confinement can change the concentrations of miRNA in sows' vMPFC and serum and the concentrations ofdepression related proteins in sows' hippocampus.