Clinical Investigation Of Piglets' Diarrhea In A Pig Farm Of Jiangsu Province And Preventive Effects Of Lactobacillus J26

Diarrhea has always been a major problem in the animal husbandry,and many factors can cause morbidity,especially Viral and bacterial fators,and often appears repeatedly,however,the diseas can hardly be eliminated completely.Diarrhea led to weight loss,stunting and decreased survival rate,which further led to a series of problems such as prolonged fattening period,decreased utilization rate of pig shed,prolonged circulation period and finally resulted in serious economic losses.The combination of multiple antibiotics is often used to prevent and control piglet diarrhea,which is effective but has many drawbacks such as bacterial resistance,gastrointestinal flora,drug residues,etc.Therefore,it's urgent to develop a healthy and effective agent to against the diseases of piglets.As a substitute for antibiotics,Probiotics not only overcome the destruction of the balance of inherent microbial communities in the digestive tract by antibiotics,but also reduce the colonization of harmful microorganisms,improve the digestion and absorption of feed,Has become the ideal feed additive in production.In this experiment,a long-term clinical tracking was conducted to analyze the causes of the piglets diarrhea in a large-scale pig farm in Jiangsu Province.And we prevented and controlled the diarrhea from the perspective of probiotics.The results showed that the J26 used as feed additive in basal diet of piglets can effectively improve the growth performance,appetite,feed utilization ratio,intestinal morphology and stool eonsistency and effectively prevent diarrhea.Experiment 1.Clinical investigation and etiological analysis of piglets diarrhea at a pig breeding farm in Jiangsu provinceThe diarrhea investigation was conducted at a large scale farm in Jiangsu province.Diarrhea occured mainly in piglets and the clinical manifestations were severe yellow or gray-yellow diarrhea,rapid weight loss,dehydration,or death,with a proportional mortality of up to 27.5%.Through necropsy,we found a large amount of gas and yellow or gray effusion in the intestinal tracts of the diseased piglets,the intestinal wall became thiner,bleeding and congested and the gastrointestinal mucosa showed acute catarrhal inflammation.The associated diarrhea viruses such as porcine epidemic diarrhea virus(PEDV),porcine transmissible gastroenteritis virus(TGEV),porcine rotavirus(PoRV)and E.coli were mixed infected through pathogen analysis.Among the pathogens,the infection rate of pathogenic E.coli was as high as 70%,followed by PEDV infection,which was approximately 42.5%.The recent survey of diarrhea in piglets found that the diarrhea in this pig farm was roughly divided into two times,one time was about one week after received the pigs,and the other was about 42-days-old.After the piglets reach 50 days of age,the diarrhea gradually disappears.The oecurrenee of diarrhea was mainly manifested as partial and not serious outbreaks or dead,and the disease stopped and recovered after medication,Usually after a few days.Pathogenic E.coli(40.0%)and PEDV(32.5%)infection were the most common causes.Therefore,the diarrhea was caused by mixed infections.Experiment 2.Isolation and identification of pathogens of diarrhea and Antibacterial test of the screened Lactobacillus J26(L.reuteri)against the isolated pathogensAccording to the colony morphology,growth characteristics of the strains and the morphological observation of the bacteria and animal pathogenicity tests,we obtained pathogenic bacteria.In the biochemical test,the pathogenic bacteria IMViC test result were”++--";Acid and gas were produced in Trisaccharide iron test and no hydrogen sulfide was produced;The WB results were consistent with the E.coli standard strain ATCC,and pathogenic E.coli were isolated.Combined with clinical medication program and related reports,appropriate antibiotics were selected to carry out drug susceptibility test on the isolated pathogens to select sensitive antibiotics.At the same time,7 strains of probiotics with highly ability of acid-tolerant,bile-resistant and adhesion,which were isolated by animal nutrition and metabolism laboratory of the Animal Medicine College of Nanjing Agricultural University,were co-cultured with the isolated pathogenic E.coli.As a result,it was found that the pathogenic Escherichia coli was completely inactivated by co-culture with Lactobacillus J26(L.reuteri)for 96 hours.Experiment 3.Prevention of piglets diarrhea by Lactobacillus J26216 piglets were randomly selected and from l,579 piglets aged 21-31-days and 7.3±0.5 kg,which were transferred from the nursery houses,and grouped into three groups:probiotic group(2 ×108),antibiotic group(composite antibiotic)and control group(normal fed),three replicates in each group,24 piglets in each replicate.In terms of the growth performance,the FCR(feed conversion ratioratio)of probiotic groups was 1.32,and the diarrhea rate was 2.78%,both significantly lower than the control group(2.78 and 15.28%).In terms of stool consistency,the probiotic group scored 3.93,significantly higher than the control group score(3.04);In terms of the morphological observation of duodenum,jejunum and ileum,the ratio of V/C of probiotics was 5.8,2.25 and 3.14,,significantly higher than the control group(4.02,1.62,and 2.80)(P<0.05).The results of the study showed that supplementing probiotic J26(L.reuteri)can effectively prevented piglets diarrhea.