The preventive effect of Bacillus subtilus strain DB9011 against experimental infection with enterotoxcemic Escherichia coli in weaning piglets

Porcine edema disease (ED) is caused by Shiga toxin 2e‐producing Escherichia coli (STEC). Post‐weaned piglets often suffer from ED as a result of intestinal infection with STEC, which causes impaired growth performance and high mortality. Antimicrobial therapy is a curative treatment for piglets infected with STEC, but the emergence of antimicrobial‐resistant STEC has become a serious problem for Japanese pig farmers. Therefore, an alternative strategy other than antimicrobial therapy is needed for the prevention or treatment of ED. In this study, we evaluated the effect of oral administration of Bacillus subtilis DB9011 (DB9011) to prevent the experimental infection of STEC in weaning piglets. Eight 21‐day‐old piglets were divided into two groups: STEC challenge with the basal diet, and STEC challenge with DB9011 supplemented diet. The challenge was carried out when the animals were 25, 26 and 27 days old using STEC contained in capsules resistant against gastric digestion. All pigs were euthanized at 36 days of age. DB9011 improved the symptoms of ED and decreased the number of STEC in the ileal digesta and feces. Accordingly, oral administration of DB9011 in weaned piglets prevents ED through the suppression of the growth of STEC in the ileum.     

Effects of a probiotic Enterococcus faecium strain supplemented from birth to weaning on diarrhoea patterns and performance of piglets

This placebo-controlled double-blind study was conducted to evaluate effects of Enterococcus faecium DSM 10663 NCIMB 10415 (EcF) orally given from birth to weaning on diarrhoea and performance of piglets. At the first 3 days postnatum (p.n.), piglets from 54 [verum group (VG)] and 60 [placebo group (PG)] sows got 1 g of a gel directly per mouth by a dosing device. Gel for the VG contained 2.8 x 10(9) colony forming units (CFU) EcF/g. From day 4 p.n. until weaning (24 +/- 3.2 days p.n.) a liquid additive was given that administered twice a day 1.26 x 10(9) CFU EcF to each VG piglet. In case of diarrhoea, an electrolyte solution was used which provided daily 2.9 and 5.8 (week 1 and >or= 2, respectively) x 10(8) CFU EcF per VG piglet. Diarrhoea scores were defined as follows: (i) no diarrhoea; (ii) piglets developed diarrhoea, but were vital and (iii) piglets suffered from diarrhoea and additionally looked pale, developed rough coat, showed slackening of the flank and lethargy. Counts of viable born, stillborn and weaned piglets were normal and not different between groups (p > 0.05). Placebo group vs. VG piglets suffered more frequently from diarrhoea (40.0 vs. 14.8%, p < 0.05). Duration of diarrhoea was not affected by feeding EcF (2.2 +/- 0.81 days, p > 0.05). Diarrhoea score was lower in VG vs. PG (1.2 vs. 1.5 +/- 0.54, p < 0.05) and the daily weight gain (DWG) was higher by 17 g/day (p < 0.05). Results suggest that the daily oral supplementation of EcF from birth to weaning reduces the portion of piglets suffering from diarrhoea. This may improve performance, as the higher DWG indicates. In contrast, no obvious benefit seems to result from an additional supply of EcF via electrolyte solution when diarrhoea is always present.     

Interaction between Bordetella bronchiseptica and toxigenic Pasteurella multocida on the nasal mucosa of SPF piglets.

The interaction between Bordetella bronchiseptica and type D toxigenic Pasteurella multocida was studied in five groups of 4 specific-pathogen-free (SPF) piglets each. At 28 days of age, piglets of groups 3 and 4 were inoculated into both nostrils with 10(8) colony-forming-units (CFU) of a non-dermonecrotic toxin (DNT)-producing, phase I strain of B. bronchiseptica. Piglets of groups 1 and 3 were treated intranasally with a sonic extract of the non-toxic strain of B. bronchiseptica and those of groups 2 and 4 with B. bronchiseptica DNT into the left nostril. Sonic extract and DNT treatment was started at 33 days of age and lasted for 5 days. Piglets of group 5 served as controls. At the age of 37 days, piglets of all groups except group 5 were inoculated into both nostrils with 5 x 10(7) CFU of toxigenic P. multocida. At slaughter at 50 days of age, P. multocida was recovered from the left nasal cavity of 3 piglets of group 2 and all piglets of group 4. In piglets inoculated with B. bronchiseptica DNT the mucosal epithelial cells of the left nasal cavity showed loss of cilia, regressive lesions such as vacuolation, karyopycnosis and necrosis, hypertrophy of the epithelium, infiltration of the epithelium and submucosa by inflammatory cells, could also be seen. The results suggest that action of the B. bronchiseptica DNT on the nasal mucosa is a precondition of the growth of P. multocida in the nasal cavity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Verification of the protective effect of a toxoid vaccine against edema disease of weaned piglets in an infection model

105 piglets (56 vaccinated and 49 control animals) were utilized in 6 consecutive experiments. Each used litter was divided randomly into vaccine and control animals. One week prior to weaning each of the 56 piglets of the vaccine groups received 5 mg of nonpurified toxin treated with glutaraldehyd subcutaneously whereas to the remaining 49 control animals an extract of apathogenic E. coli was administered. During the first 12 hours post weaning each of the 105 piglets was challenged perorally with 10(10) cfu of edema principle toxin producing germs of E. coli serogroup O 139. 23 animals of the control groups (46.9%) and one animal of vaccine groups (1.8%) died due to the infection between days four and five post challenge. These control animals showed classical clinical symptoms as well as pathological findings typical for edema disease. In contrast, such findings as mentioned before could not be observed in the vaccinated piglets. The remaining part of the control animals and eight of those vaccinated ones exhibited edema disease symptoms. The vaccinated animals have shed the challenge strain one to three days, while the survivals of control groups shed those germs for two to six days. The vaccinated piglets showed a better growth rate than the remaining control animals. Presented data suggest that our toxoid immunizing procedure can be used successfully against edema disease of swine.     

Improved porcine model for Shiga toxin‐producing Escherichia coli infection by deprivation of colostrum feeding in newborn piglets

Porcine edema disease (ED) is a toxemia caused by enteric infection with Shiga toxin 2e (Stx2e)‐producing Escherichia coli (STEC). ED occurs most frequently during the weaning period and is manifested as emaciation associated with high mortality. In our experimental infection with a specific STEC strain, we failed to cause the suppression of weight gain in piglets, which is a typical symptom of ED, in two consecutive experiments. Therefore, we examined the effects of deprivation of colostrum on the sensitivity of newborn piglets to STEC infection. Neonatal pigs were categorized into two groups: one fed artificial milk instead of colostrum in the first 24 h after birth and then returned to the care of their mother, the other breastfed by a surrogate mother until weaning. The oral challenge with 10¹¹ colony‐forming units of virulent STEC strain on days 25, 26 and 27 caused suppression of weight gain and other ED symptoms in both groups, suggesting that colostrum deprivation from piglets was effective in enhancing susceptibility to STEC. Two successive STEC infection experiments using colostrum‐deprived piglets reproduced this result, leading us to conclude that this improved ED piglet model is more sensitive to STEC infection than the previously established models.     

Evaluation of the low dose level of a heat-killed and dried cell preparation of Enterococcus faecalis to prevent porcine edema disease using experimental infection model with enterotoxcemic Escherichia coli in weaning pigs

Porcine edema disease (ED) is caused by Shiga toxin 2e-producing Escherichia coli (STEC). ED has become frequent in pig farms, and the use of antimicrobials has resulted in the development of antimicrobial-resistant STEC. Accordingly, the use of materials other than antimicrobials is requested for the prevention of ED. Oral administration of a heat-killed and dried cell preparation of Enterococcus faecalis strain EC-12 (EC-12) to weaning pigs was previously demonstrated to decrease animal mortality in a STEC-contaminated farm at 0.05% (w/w) dose level. In this study, pigs experimentally infected with STEC were used as a model for ED to evaluate the low dose level of EC-12 to prevent ED. Fifteen 21-day-old pigs were divided into 5 groups: STEC challenge with the basal diet, STEC challenge with EC-12 supplemented at 0.005, 0.01, or 0.05% (w/w) to the basal diet, and no STEC challenge with the basal diet. The challenge was carried out when the animals were 25, 26, and 27 days old using STEC contained in capsules resistant against gastric digestion. All pigs were euthanized at 32 days of age. The daily weight gain, feed conversion ratio, and palpebral edema were improved by supplementation with 0.05% EC-12, but not by the low dose levels. Accordingly, 0.05% level of supplementation was needed for EC-12 to improve clinical symptoms in weaning piglets infected by STEC.     

Pathogenicity of Salmonella enteritidis phage types 4, 8, and 23 in broiler chicks.

Four hundred fifty day-old Hubbard broiler chicks were subdivided into 15 groups of 30 chicks each. Six groups of chicks received 0.5 ml of broth culture containing 5 x 10(6) colony-forming units (CFU) of Salmonella enteritidis (SE) phage types (PTs) 4, 8, and 23 by crop gavage. Similarly, six other groups received 0.5 ml containing 5 x 10(8) CFU of SE. One group was inoculated with 0.5 ml containing 5 x 10(6) CFU of Salmonella pullorum, and another group received 0.5 ml containing 5 x 10(8) CFU of S. pullorum. A group of 30 chicks were kept as uninoculated controls. Chicks were observed daily for clinical signs and mortality. All birds were weighed at 7, 14, and 21 days postinoculation 21 (DPI). Four chicks were randomly selected from each treatment group, euthanatized, and necropsied at 7 and 14 DPI. Gross lesions were recorded and selected tissues were collected for histopathology. The higher rates of illness and mortality were observed in chicks inoculated with 5 x 10(6) and 5 x 10(8) CFU of S. pullorum, followed by SE PT4 of human origin and SE PT4 of chicken origin. Moderate to high mortality was observed in chicks inoculated with the higher dose of SE isolates that belonged to PT8 and one SE of PT23. Variable mortality was evident in groups inoculated with the lower dose of salmonella. The most consistent gross and histopathologic changes, including fibrinous pericarditis and perihepatitis, were seen in the dead birds from various treatment groups. The lower mean body weights were present in all treatment groups compared with uninoculated controls. No illness or mortality was observed in uninoculated control groups.     

Evaluation of the German cockroach (Blattella germanica) as a vector for verotoxigenic Escherichia coli F18 in confined swine production

German cockroaches are common pests of confined swine production in North Carolina and other southeastern states. Vector competence of German cockroaches for one of the most important porcine bacterial pathogens, verotoxigenic Escherichia coli F18, was evaluated in laboratory bioassays using a culturing approach followed by multiplex PCR. In addition, the populations of fecal coliforms from the feces of piglets and cockroaches collected from a swine nursery were assessed. Viable and virulent cells of E. coli F18 were detected in cockroach feces for up to 8 days after the initial exposure. The population of fecal coliforms in cockroach feces was high (4.4 x 10(5) CFU g(-1)) and comparable to that of piglet feces (1.9 x 10(6) CFU g(-1)). This study demonstrates that cockroaches may serve as important mechanical vectors of pathogenic E. coli. Integrated management of cockroach populations should be incorporated into the disease prevention and control programs in the swine industry.     

Effects of Recombinant E. coli Expressing Heat-stable Enterotoxin on Intestinal Morphology and Antioxidant Capacity in Seven Days old Piglets

This experiment was conducted to investigate the effects of recombinant E.coli expressing heat-stable enterotoxin(STa) on intestinal absorption and barrier function, intestinal morphology and antioxidant capacity of 7 days old piglets. Twenty-four 7 days old piglets were allotted to four treatments:control group (artificial milk), STa group (artificial milk +2×10⁹ CFU E.coli LMG194-pBAD-STa), LMG194 group (artificial milk +2×10⁹ CFU E.coli LMG194), and K88 group (artificial milk +2×10⁹ CFU E.coli K88).The pigs were treated with E.coli on the 5th day and slaughtered on the 7th day. The results showed that, compared with the control group, villus height in jejunum, ileum and duodenum, crypt depth and villus height/crypt depth in duodenum, and small intestine villi surface area were significantly decreased in STa group (P<0.05). The activities of catalase (CAT) in ileum and colon, total nitric oxide synthase (TNOS) in serum, ileum, jejunum and colon, inducible nitric oxide synthase (iNOS) in colon were significantly decreased in STa group (P<0.05). STa group also had a higher levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) in serum (P<0.05). These results suggested that recombinant E.coli expressing STa could lead to intestinal injury and oxidative stress of 7 days old piglets.     

表达耐热肠毒素的重组大肠杆菌对7日龄仔猪肠道形态结构及抗氧化功能的影响

试验旨在研究表达耐热肠毒素（STa）的重组大肠杆菌对7日龄仔猪肠道形态结构及抗氧化功能的影响。选取24头7日龄仔猪,随机分在4个日粮处理组,分别为对照组（人工乳）,STa组（人工乳+2×10⁹ CFU重组菌LMG194-pBAD-STa）,LMG194组（人工乳+2×10⁹ CFU大肠杆菌LMG194）,K88组（人工乳+2×10⁹ CFU大肠杆菌K88）。试验第5天进行攻毒,第7天屠宰取样,测量小肠黏膜的绒毛高度和隐窝深度,检测空肠、回肠、结肠及血清中的过氧化氢酶（CAT）、总一氧化氮合成酶（TNOS）与诱导型一氧化氮合酶（iNOS）的活力及血清中丙二醛（MDA）与过氧化氢（H₂O₂）的含量。试验结果表明,与对照组相比,STa组仔猪各肠段绒毛高度均显著降低（P<0.05）,十二指肠隐窝深度及绒毛高度与隐窝深度的比值显著降低（P<0.05）,十二指肠、空肠、回肠绒毛表面积显著降低（P<0.05）;同时,STa组回肠、结肠CAT活力显著降低,血清、空肠、回肠和结肠中的TNOS活力显著降低（P<0.05）,STa组结肠iNOS活力显著降低（P<0.05）,STa组血清中的MDA与H₂O₂含量显著提高（P<0.05）。结果显示,表达STa的重组大肠杆菌可导致7日龄仔猪肠道结构损伤和抗氧化能力下降。     

Protective effect of oral administration of transgenic tobacco seeds against verocytotoxic Escherichia coli strain in piglets

The use of transgenic plants as delivery system for antigenic proteins is attractive for its simplicity and increases likelihood for local immune response at sites of infection. The aim of this study was to evaluate the protective effect of oral administration of tobacco seeds, expressing the FedA, the major protein of the F18 adhesive fimbriae, and B subunit of verocytotoxin, against verocytotoxin-producing E. coli (VTEC) strain in piglets. Forty-three early weaned piglets, were randomly divided into 4 experimental groups: 3 test groups and a control. Treatment groups orally received a bolus, with different dose of tobacco seeds on 0, 1, 2, 14 days post primary administration. After challenge, with 1*10¹⁰ CFU of O138 Escherichia coli strain, piglets showed clinical scores significantly higher in the control group compared to orally immunized groups (P?<?0.05) and the latter showed a faster recovery than in CG. In conclusion, oral administration of recombinant tobacco seeds expressing antigenic proteins against VTEC strains can induce a protective effect against challenger strain in piglets.     

Responses of cattle to two dosages of Brucella abortus strain RB51: serology, clearance and efficacy

A new brucellosis vaccine, Brucella abortus strain RB51 (SRB51), is currently recommended for use as a calfhood vaccine in the US at dosages between 1 x 10(10)and 3.4 x 10(10)colony-forming units (CFU). The purpose of the study reported here was to compare responses to minimal and maximal recommended SRB51 dosages. Eighteen heifer calves were vaccinated subcutaneously with 1.6 x 10(10)CFU of SRB51, 3.2 x 10(10)CFU of SRB51, or saline (n = 6 per treatment). The vaccine strain was recovered from the superficial cervical lymph node 14 weeks after vaccination in two of six animals that received 1.6 x 10(10)CFU SRB51, but not from any cattle vaccinated with 3.2 x 10(10)CFU SRB51. The higher SRB51 dosage stimulated greater antibody titres. Protection against abortion or infection following B. abortus strain 2308 (S2308) challenge was similar for both SRB51 dosages and greater than resistance of non-vaccinates. The vaccine strain was recovered from one heifer and her fetus at necropsy 1 week prior to estimated parturition. Data from this study suggests that SRB51 induces similar protective immunity across the recommended dosage range. The SRB51 vaccine may persist in some cattle into adulthood but the incidence and significance of this persistence remains unknown.     

The prevention of atrophic rhinitis of swine

In a pig breeding unit that for years had been infected with Atrophic Rhinitis, the weaned piglets were divided into four groups. Group 1 (10 weaned piglets) --Their mother was vaccinated with 2 ml Rhinipig i.m. 3 weeks prior to farrowing. --The piglets received 0.2 ml each of Pargenta 50 (= 10 mg Gentamycin) i.m. on the third, fifth and seventh days after birth. --The piglets were fed a food containing 10 ppm Gentamycin-base during the 6 weeks following their weaning. Group 2 (10 weaned piglets) --Their mother was vaccinated with 2 ml Rhinipig i.m. 3 weeks prior to farrowing. --The piglets received 0.2 ml each of Pargenta 50 (= 10 mg Gentamycin) i.m. on the third, fifth and seventh days after birth. Group 3 (10 weaned piglets) --Their mother was vaccinated with 2 ml Rhinipig i.m. 3 weeks prior to farrowing. Group 4 (10 weaned piglets, untreated, experimental control group) After 6 weeks of treatment, Group 1 showed significantly better food conversion and daily weight gain when compared to the other groups.     

Hormonal profiles of late gestation ewes following intra-uterine inoculation with and without lux-modified Escherichia coli

The objectives of these investigations were to develop an ovine model for Escherichia coli (E. coli)-induced preterm delivery, and monitor ewe hormonal response. EXP 1: Ewes (105 +/- 13 days of gestation) were allotted to the following intra-uterine inoculations: Saline-(CON; n=5); 1 x 10(6) CFU/ml (Low Treatment, LT; n=6); or 1 x 10(7) CFU/ml (High Treatment, HT; n=6) E. coli. Twenty-four h after inoculation, the HT ewes had increased (P<0.05) cortisol compared to LT and CON ewes, and HT and LT ewes had increased (P<0.05) progesterone compared to CON ewes. Preterm delivery was 33% for LT ewes and 0% for HT and CON ewes. EXP 2: Ewes (124 +/- 18 days of gestation) were allotted to the following intra-uterine inoculations using lux-modified E. coli: Trial-1: Luria Broth (LB; CT1; n=5); 4.0 x 10(6) CFU (n=5), 20.0 x 10(6) CFU (n=5); and Trial-2: LB (CT2; n=5), 1.2 x 10(6) CFU (n=5), and 5.6 x 10(6) CFU (n=5) E. coli-lux. Preterm delivery occurred between 48 and 120 h post-inoculation in 60, 25, 60 and 75% of ewes infected with 1.2, 4.0, 5.6, and 20 x 10(6) CFU, respectively. Serum cortisol and progesterone did not differ (P>0.05) between CT1 or CT2 and inoculated ewes. In summary, 25 to 75% of ewes inoculated preterm delivered. However, variable results in cortisol and progesterone profiles between Control and inoculated ewes were observed between the two studies.     

表达猪乳铁蛋白肽重组屎肠球菌对断奶仔猪生长性能的影响及其抗ETEC感染效果研究

本试验以表达猪乳铁蛋白肽的重组屎肠球菌（pNZ8112-PLFcin/Ef）饲喂断奶仔猪，研究其对仔猪生长性能的影响和抗产肠毒素大肠杆菌（enterotoxigenic Escherichia coli，ETEC）感染的效果。选取28日龄体重相近的健康断奶仔猪36头，随机分为3组（重组屎肠球菌组、空载体组和培养基组），每组3个重复，每个重复4头仔猪。重组屎肠球菌组和空载体组分别饲喂添加pNZ8112-PLFcin/Ef （6×10¹² CFU/kg）和pNZ8112/Ef （6×10¹² CFU/kg）的基础日粮，而培养基组饲喂含有相同体积的GM17液体培养基的基础日粮。试验期26 d。结果显示，与培养基组相比，重组屎肠球菌组断奶仔猪的平均日增重极显著提高（P<0.01）；料重比显著降低（P<0.05）；腹泻率明显降低，肠道菌群的均匀度和多样性指数均下降。为进一步探究表达猪乳铁蛋白肽的重组屎肠球菌对断奶仔猪抵抗ETEC感染的保护作用，在连续饲喂21 d后，每个重复中随机挑选1头体况相近的断奶仔猪灌服ETEC。结果发现，与培养基组相比，攻菌后重组屎肠球菌组断奶仔猪血清白细胞介素-2（IL-2）、免疫球蛋白G （IgG）含量、肠黏液中分泌型免疫球蛋白A （sIgA）水平均显著升高（P<0.05）；脾脏指数显著提高（P<0.05），但胸腺指数、肠段长度及重量则均无显著差异（P>0.05）。综上所述，表达猪乳铁蛋白肽的重组屎肠球菌能够起到促进断奶仔猪生长及抗ETEC感染的保护作用。     

Protection against neonatal Escherichia coli diarrhoea in pigs by vaccination of sows with a new vaccine that contains purified enterotoxic E. coli virulence factors F4ac, F4ab, F5 and F6 fimbrial antigens and heat-labile E. coli enterotoxin (LT) toxoid

The efficacy of a new vaccine against neonatal Escherichia coli diarrhoea in piglets containing purified F4ab, F4ac, F5 and F6 fimbriae and detoxified heat-labile toxin (LT) was tested in challenge experiments by the method described by the European Pharmacopoeia (3rd edn, EDQM, Council of Europe, Strasbourg, France). A group of 11 young sows from a herd without E. coli problems was vaccinated 6-8 and 2-4 weeks prior to expected farrowing and another group of nine young sows were non-vaccinated controls. Escherichia coli antibody titres were determined in serum samples taken from the sows before first vaccination and before farrowing and in colostrum samples. The newborn piglets were allowed to suckle colostrum from their mother immediately after birth. The piglets were marked with individually numbered ear tags. Approximately 12 h after birth, 118 piglets from vaccinated sows and 79 piglets from non-vaccinated control sows were challenged by oral instillation of 5 ml of a freshly prepared culture of one of the challenge strains [O8:K87:F4ab (LT+) or O149:K91:F4ac (LT+) or O9:K30:F5 or O9:K103:F6 respectively]. The challenge cultures contained as a mean 6.8x10(9) CFU/ml. After challenge the piglets were observed for 7 days and mortality and morbidity were recorded. Vaccinated sows developed significant levels of antibody titres in colostrum and serum. Control sows stayed at a low/seronegative level. The protective efficacy was excellent because 66.7-87.5% of the piglets from vaccinated sows remained without clinical signs after challenge. Only 0.0-28.0% of the piglets from non-vaccinated sows remained healthy and more than 47.1% of the piglets in this group died after challenge. It is concluded that the new vaccine is very effective in protection of piglets against neonatal E. coli diarrhoea.     

The effect of combined antibiotic and immune prophylaxis against atrophic rhinitis on the body weight of swine

In a natural outbreak of Atrophic Rhinitis, the weaned piglets were divided into four groups. Group 1 (10 weaned piglets); Their mother was vaccinated with 2 ml Rhinipig i. m. 3 weeks prior to farrowing. The piglets received 0.2 ml each of Pargenta 50 (= 10 mg Gentamycin) k. m. on the third, fifth and seventh days after birth. The piglets were fed a food containing 10 ppm Gentamycin base during the 6 weeks following their weaning. Group 2 (10 weaned piglets); Their mother was vaccinated with 2 ml Rhinipig i. m. 3 weeks prior to farrowing. The piglets received 0.2 ml each of Pargenta 50 (= 10 mg Gentamycin) i. m. on the third, fifth and seventh days after birth. Group 3 (10 weaned piglets); Their mother was vaccinated with 2 ml Rhinipig i. m. 3 weeks prior to farrowing. Group 4 (10 weaned piglets, untreated, experimental control group). The results were during the growing period (from 12.3 kg to 32-34.9 kg) and during the finishing period (from 32-34.9 kg to 100 kg) evaluated. Group 1 showed significantly better food conversion and daily weight gain in both periods when compared to the other groups. Although the difference of daily weight gain between Group 1 and Groups 2 and 3 where diminished by 4.34% respectively 1.72%.     

Prevention of edema disease in pigs by passive immunization.

The effect of treatment with verotoxin 2e (VT2e) specific antiserum was evaluated in 3 Danish pig herds with edema disease (ED). The antiserum was prepared by immunizing horses with a VT2e toxoid. The study was performed as a randomized blind field trial with parallel treatment and control groups. There were approximately 50 piglets in each group in each of the 3 herds and 741 piglets were included in the study (244 from herd A, 249 from herd B, and 247 from herd C). Treatment groups received 2, 4, or 6 mL anti-VT2e serum intramuscularly the day before weaning. Control groups were treated with 6 mL normal horse serum or 6 mL RPMI 1640 medium as placebo. All pigs that died in the trial period (1 d before weaning to 44 d after weaning) were examined pathologically and microbiologically. Mortality due to ED, mortality due to other causes, and adverse effects due to treatment were recorded. As there was no mortality due to ED, herd B was excluded from statistical calculations on mortality. The content of horse antibodies specific to VT2e in serum from pigs was analyzed in an indirect ELISA. A higher dose of anti-VT2e serum was reflected in higher optical density values in the indirect ELISA. Transient adverse reactions, seen as vomiting, ataxia, and cyanosis, occurred shortly after the injection of horse serum in 1.5% of the pigs, and one pig died. There were no statistically significant differences in mortality due to other causes among the 3 treatment groups in herds A and C. Only pigs from which F18+, VT2e+, ST-, LT- hemolytic E. coli (0139 or O-rough) was isolated were diagnosed as dead due to ED. Deaths due to ED in the control groups were 8.1% and 12.0% in herds A and C, respectively, compared with 0% and 0.7% in the corresponding serum groups. The difference between treatment and control groups was statistically significant (P<0.0001). It was not possible to establish an effect of dose (2, 4, or 6 mL) of anti-VT2e serum, because only one pig died of ED in the treatment groups. It was concluded that passive immunization by intramuscular injection of a VT2e-specific antiserum can be used for protecting piglets against ED.     

Comparison of four immune variables and pulmonary lesions of goats with intrapulmonary exposure and subsequent intrathoracic challenge exposure with Pasteurella haemolytica

A comparison of immune variables following lung sensitization with live Pasteurella haemolytica serotype 1 (Ph1)-impregnated agar beads was done in 2 separate trials. The Ph1 immune variables studied were blood bactericidal activity, serum bacteriolysis, total classical complement, and indirect hemagglutination antibody. Each trial had 16 male weanling goats: 6 controls and 10 principals. In trial 1, each goat was surgically catheterized through the trachea, then the material was deposited in a bronchus. The controls received only agar beads and the principals received agar beads impregnated with live Ph1. These goats were studied for 32 days, euthanatized, and necropsied. In trial 2, the controls were each transthoracically injected with agar beads into the left lung and the principals were similarly injected with agar beads impregnated with live Ph1. These goats were studied for 35 days, then challenge exposed transthoracically by injection of Ph1 in saline solution (1.2 x 10(7) CFU/ml) into the right lung. Four days later, they were euthanatized and necropsied. The volume of lung consolidated tissue was an excellent measure of Ph1 immunity. Principal goats generated solid protective immunity to subsequent challenge exposure because minimal or no lung consolidation was observed, whereas large volumes of lung consolidation were seen in the controls. The principal goats in trial 1 gave a weak serum indirect hemagglutination Ph1 antibody response, which was attributed to the bronchial method of depositing the Ph1. The corresponding response of the control group remained negative. The Ph1 agar beads (1 x 10(6) CFU in 0.5 ml) protected the bacteria from immediate phagocytosis and lysis as indicated by the induced pneumonic deaths of 2 principals 5 days later.(ABSTRACT TRUNCATED AT 250 WORDS)     

屎肠球菌WEI-10对断奶仔猪的安全性评价

本试验在饲粮中添加屎肠球菌(Enterococcus faecium)WEI-10,通过对断奶仔猪活跃状态、腹泻分数、生长性能、菌血症以及组织病理学的检测,评价菌株WEI-10对断奶仔猪的安全性。设计2批试验,每批选取26日龄的断奶仔猪253头,平均体重分别为(7.44±1.02)和(8.11±1.51)kg,每批试验分为2组:对照组饲喂基础饲粮(不添加抗生素和益生菌),试验组饲喂在添加基础饲粮中添加菌株WEI-10的试验饲粮(2批试验的试验组每克基础饲粮中添加量分别为1×108和1×107CFU)。每批试验38 d。结果表明:1)2批试验的试验组与对照组,在活跃分数、平均日增重和料重比上均无显著性差异(P0.05)。2)试验组在第5、10和38天腹泻分数均显著性低于对照组(P0.05);第38天,试验组的腹泻分数降为0,对照组腹泻分数在0.6左右。3)2批试验的试验组和对照组均未出现菌血症以及心脏、肝脏、脾脏、肺脏、肾脏、十二指肠和空肠的病理学改变。由此可见,菌株WEI-10对断奶仔猪不存在安全问题,并且可以减少腹泻。