Effect Of Positive Handling On Behavior,Welfare,Performance And Intestinal Microbiota Of Pigs

Human–animal relationship was an important part of management in modern husbandry production,and an important component of farm animal welfare.Poor treatment of farm animals increased the anxiety of animals and caused difficulties in their handling and management.This worsened the human–animal relationship and had a negative impact on production performance and welfare.Gentle and positive human-animal interaction might reduce pig fear of humans.However,the existing research only focused on the effects of shortterm human-animal handling on pig behavior,production performance and physiology and there is little research about effects of long-term positive handling.Therefore,from the perspective of long-term positive handling,the effects of positive handling on production performance,meat quality,behavior of growing pigs,behavior,physiology and fecal microorganism of pregnant sows,the behavior,physiology and production performance of lactating sows and intestinal health of piglets were investigated in this research in order to find a new way to improve the level of pig welfare and to provide theoretical support for the application of positive handling in pig production practice.In experiment 1,the validity of the handling method was verified by measuring the behavioral,physiological and immune responses of weaned piglets with handling experience.144 6-week-old hybrid weaned piglets(Yorkshire×Duroc×Min)were selected in this experiment,and divided into a handling group and a control group,each group had 9 replicates,each replicate had 8 pigs.After 6-week handling,2 piglets were randomly selected from each replicate to behavioral scoring(AA test)and tested the animal’s behavioral response to different experimenters(familiar or strange experimenters),using focal animal sampling and instantaneous recording methods to record the animal’s behavior to the experimenter and testing heart rate,levels of salivary s Ig A,AMY,TNF-α,and serum IFN-γ,Ig A,Ig G,Ig M,IL-1β,IL-2,IL-3,IL-6,and IL-10.The results showed that after 6-week handling,in unfamiliar environment,whether familiar or strangers,the AA test score and the number of contact with the experimenter in the handling group were significantly higher than those in the control group(p<0.05),while the pigs in the control group showed more avoidance behavior(p<0.05),looking at the experimenter behavior(p<0.05),There was no significant difference in AA test score,contact behavior,looking at the experimenter behavior and avoidance behavior between the handling group and the control group(p>0.05).Compared with the control group,piglets in the handling group showed more no-contact behaviors with familiar people(p<0.05),but there was no difference in the no-contact behavior with strangers compared with the control group(p>0.05),piglets facing the familiar showed more no-contact behavior with strangers,but the difference was not significant(p>0.05);There was no significant difference in heart rate and salivary cortisol and AMY level between the handling group and the control group(p>0.05).The s Ig A and Ig M levels after the test of familiar people was lower than that with the stranger in handling group(p<0.05).The IL-6 level of piglets after the test of familiar people in the handling group was higher than that of strangers(p<0.05),that was not significant in the control group(p>0.05),while the level of IL-6 in the stranger group was not significant(p>0.05).The difference of level of TN-α,IFN-γ,Ig A,Ig G,IL-1β,IL-2,IL-3 and IL-10 in piglets was not significant between the handling group and the control group(p>0.05).In experiment 2,the effects of long-term(weaning to slaughter)positive handling on pig production performance and meat quality were explored.this experiment was divided into two stages: growing period and fattening period.144 6-week-old hybrid weaned piglets(Yorkshire×Duroc×Min)were selected and divided into the handling group and the control group: each group had 9 replicates,each replicate had 8 piglets.After 6 weeks of handling,the production performance was recorded.Then 3 pigs from each 18 pens were randomly selected and then put into the fattening house and divided into the handling group(3 pens * 9 piglets)and the control group(3 pens * 9 piglets).Pigs were raised up to slaughter.By end of measuring production performance,carcass quality and meat quality were measured.Results showed that the average daily gain,average daily feed intake and meat feed ratio between the two groups were not significantly affected(p>0.05).At 45 min,the b* value of the handling group was significantly lower than that of the control group(p=0.002).L value of the handling group at2 h was significantly higher than that of the control group(p=0.047),and carcass quality and other meat quality indexes were not significant between the two groups(p>0.05).In experiment 3,the effect of long-term positive handling(contact + food award)on the behavior and salivary physiology and immunity of pregnant sows were explored,72 first-born hybrid Dumin gilts(Duroc × Min)were selected and divided into two groups: the control group(n=36)and the handling group(n=36),which were divided into 12 pens with 6 gilts per pen.The experiment started artificial insemination until they were transferred to the farrowing room(the 7th day before the expected date of farrowing).On the 25 th,45th,65 th,85th and 105 th day after mating,one gilt from each column was randomly selected to record state behaviors.On the next day after behavior observation,one gilt from each column was randomly selected for saliva collection.The levels of salivary cortisol,s Ig A and AMY in were measured by ELISA and fecal microbial analysis was conducted.Results showed that with the increase of time,standing behavior,lateral lying behavior and ventral lying behavior of the handling group and the control group showed a significant trend of change(p<0.05),change trend of siting behavior was not significant(p>0.05),In different experimental stages,there was no significant difference in the proportion of standing behavior,lateral lying behavior,ventral lying behavior and sitting behavior between the handling group and the control group(p>0.05);the number of bar-biting behavior in the handling group was significantly lower than that in the control group on the 45 th day of the experiment(p<0.05),and there was no significant difference between the two groups at other observation points(p>0.05).In different experimental stages,there was no significant difference of vacuum chewing,exploring and grooming behavior between the handling group and the control group(p>0.05).There was no significant difference in the levels of cortisol,salivary amylase and s Ig A between the handling group and the control group(p>0.05).There were no significant differences in Alpha diversity between the control group and the handling group at 5 gestational time points(p>0.05),and there were significant differences in fecal microbial composition between the handling group and the control group at day 26 and 46 of gestation(p<0.05).There was no difference in the relative abundance of Firmicutes,Bacteroidetes and Spirochaetes between the two groups at the 26 th,46th,66 th,86th and 106 th days of gestation(p>0.05).The relative abundance of Oscillospira in the handling group and the control group was significantly different during the whole pregnancy(p<0.05).In experiment 4,the effect of positive handling during pregnancy on behavior,physiology,colostrum physiology and production performance of lactating sows was explored,34 sows were selected from the handling group of the experiment 3 and 32 sows were selected from the control group of the experiment 3 and divided into the handling group(n=34)and the con trol group(n=32).Six sows were randomly selected from each group to observe and record the nesting behavior 24 hours before farrowing,the state behaviors of day 1-3 and week 2-4 after farrowing,posture change of day 1-3 and week 2-4 after farrowing,and the lactation behavior of week 2-4 after farrowing.The concentrations of prolactin and oxytocin in feces on the 2nd day before farrowing,2nd and 5th day after farrowing and the concentrations of Ig A,Ig M,Ig G and lactoferrin(LTF)in colostrum were detected.At the same time,production performance of sows and the diarrhea situation of each litter of piglets and the diarrhea rate were recorded and calculated.5 piglets were randomly selected from each group and slaughtered on day 30 after parturition.The microstructure of jejunum,ileum,colon and cecum of piglets were observed,and the indexes related to immune and intestinal barrier were detected by q RT-PCR and Western Blot,as well as intestinal microbial analysis.The results showed that there was no significant difference between the handling group and the control group(p>0.05)in the number of prenatal24-hour nesting behavior.The prenatal nesting behavior began to increase in 12 hours before farrowing and reached the peak in 6 hours before farrowing.There was no significant difference between the handling group and the control group in the expression of state behavior and lactation behavior and the frequency of posture change within 3 days and week 2-4 after farrowing(p>0.05),there was a significant change in the handling group and the control group(p<0.05).There was no significant difference in the levels of oxytocin and prolactin between the two groups(p>0.05)and the levels of Ig G,Ig A,Ig M and lactoferrin in colostrum between the handling group and the control group(p>0.05),and there was no significant difference in the production performance of sows and diarrhea rate of lactating piglets between the handling group and the control group(p>0.05).Positive human-animal handling during pregnancy did not change the diversity and composition of microorganisms in each intestinal tract of piglets(p>0.05),and there was no difference in tissue structure between groups.Positive humananimal interaction during pregnancy up-regulated m RNA expression levels of Claudin-1,Occludin,MUCin-2,ZO-1 and TLR4 in jejunum,ileum,colon and cecum of piglets(p<0.05).The m RNA expression levels of IL-1β,IL-6,IL-8 and TNF-α in jejunum,colon and cecum were up-regulated(p<0.05),and IL-6 m RNA expression levels in ileum were down-regulated(p<0.05).Conclusion: After 6-week handling,pigs showed less fear to human,more willing to approach people,and the intimacy of piglets with people increased.Although positive handling had little effect on physiology and immunity of weaned piglets,the levels of s Ig A and IL-6,which reflect positive emotional state,were higher in saliva of weaned piglets in the handling group;Long-term positive handling has little effect on the production,carcass quality and meat quality of pigs.After a short period(45 days)of positive handling,there was a significant impact on the bar-biting behavior and fecal microbial diversity of gestation sows.The positive handling during the whole gestation period had not evident effect on the behavior,salivary physiological immunity and fecal microbiota of sows,as the same on maternal ability,physiology and immunity of colostrum and productivity in lactating sows and effect on piglets was restricted.