Swine fever. Immunisation of piglets

Vaccination against Swine Fever using the CL Chinese strain can be done in 7-day-old piglets if they are born of non-immune sows. The simultaneous weaning and vaccination emphasises the safety of this strain. The excellent immunity observed confirms the immunocompetence of 7-day-old piglets. In piglets born of immune sows and also weaned at 7 days, passive protection can extend beyond the age of 2 months if the sow is vaccinated several months prior to gestation. The immune level of the piglets would seem to depend on the interval between vaccination of the sow and farrowing and can be attributed to the quality of the antibodies transmitted by the colostrum. Piglets born of sows vaccinated 10 months prior to farrowing can be vaccinated as early as 5 weeks; the protection percentage observed at the age of about 6 months is over 80%. A booster injection at this age then confers immunity to future breeders throughout their economic life, i.e. 4 years in the reported experiment.     

普那菊苣引种适应性观察

通过对引进的普那菊苣进行3年的种植试验，结果表明，普那菊苣在四川大部分地区表现良好，具有较强的适应性、抗逆性和再生能力，生长利用期长，生长速度快；一年可以刈割7～8次，产草量高，年鲜草产量180～225 t/hm~2；牧草品质好，营养价值高，干物质粗蛋白含量达15%～32%，利用率高，寿命长，适宜在四川气候温暖湿润的地区生长。     

普那菊苣引种适应性观察

通过对引进的普那菊苣进行3年的种植试验,结果表明,普那菊苣在四川大部分地区表现良好,具有较强的适应性、抗逆性和再生能力,生长利用期长,生长速度快;一年可以刈割7～8次,产草量高,年鲜草产量180～225 t/hm2;牧草品质好,营养价值高,干物质粗蛋白含量达15%～32%,利用率高,寿命长,适宜在四川气候温暖湿润的地区生长.     

Immunisation against infections caused by Listeria monocytogenes in sheep

Immunisation against listeriosis in sheep using a live, attenuated vaccine was introduced in Norway in 1984. Since then 65,000 to 80,000 animals have been vaccinated annually. Information obtained by a questionnaire showed that the incidence of listeriosis decreased from approximately 4.0 per cent before the introduction of the vaccine to 1.5 per cent after vaccination started. The incidence of abortions was 0.7 per cent in vaccinated flocks compared to 1.1 per cent in unvaccinated flocks. There were a few adverse reactions in the vaccinated sheep.     

Immunisation of pigs with live cultures of Streptococcus suis type 2

Repeated intravenous injections of pigs with live virulent cultures of Streptococcus suis type 2 stimulated a strong protective response against subsequent challenge. This protection was transferred passively to susceptible pigs by the inoculation of sera from protected pigs. A strong protective response was also stimulated by repeated inoculations of live cultures of non-pathogenic isolates. The protective response did not eliminate S suis type 2 organisms already established in the tonsils or joints, nor prevent the establishment of subclinical infection in the tonsils.     

Immunisation of pigs with killed cultures of Streptococcus suis type 2

Ten intravenous inoculations of 10(10) formalin-killed pathogenic Streptococcus suis type 2 stimulated detectable levels of opsonic antibody and a strong protective response against intravenous challenge with 10(9) viable S suis type 2 of the same strain. Heat-killed organisms did not stimulate a protective response, even though the type-specific antigen was intact and opsonic antibodies were induced. When the number of formalin-killed organisms in the inoculum was increased 10-fold, one inoculation was insufficient to stimulate a protective response, but two inoculations protected pigs against intravenous challenge with live, pathogenic organisms. Four-hour and overnight cultures were equally immunogenic, and the response was not enhanced by either Freund's incomplete adjuvant or aluminium hydroxide gel adjuvant.     

Immunisation of pregnant sows with a live Salmonella cholerae suis vaccine

Sows were immunised subcutaneously with a live Salmonella cholerae suis (SCS) vaccine prior to farrowing. Serological tests demonstrated a high level of SCS colostral antibodies at parturition. Piglet sera negative for antibodies at birth contained a high level of SCS antibodies 24 h after the ingestion of vaccinated sow colostrum. Experiments were carried out to establish if these maternally derived antibodies could protect the piglets against an intranasal (IN) challenge with a field isolate of SCS. It was concluded that pregnant sows could be safely immunised with a live SCS vaccine thus providing their piglets with a passive immunity which protected them against an intranasal challenge.     

Immunisation of sheep against experimental Pseudomonas aeruginosa dermatitis and fleece-rot associated body strike

Sheep immunised with an experimental Pseudomonas aeruginosa vaccine and unvaccinated control sheep were challenged by induction of experimental dermatitis with the homologous strain. All of 6 control sheep developed ulcerative dermatitis, and 2 of the 6 challenge sites were struck by larvae of Lucilia cuprina. Neither severe dermatitis nor strike occurred in 6 vaccinated sheep. These results were confirmed in an experimental challenge using 3 different serotypes of P. aeruginosa on each of 3 vaccinated and control sheep, although fly-strikes did not occur. In a field trial of the same vaccine, none of 26 vaccinated sheep developed severe exudative, fleece-rot lesions nor were any fly-struck, whereas 61 of 115 control sheep developed severe, exudative, fleece-rot lesions, 21 of these becoming struck by L. cuprina. The isolates of P. aeruginosa recovered from the field challenge experiment were a different serotype to that used in the vaccine.     

The Effects of Wound Lavage Solutions on Canine Fibroblasts: An In Vitro Study

Objective —The purpose of this study was to determine the effects of phosphate-buffered saline (PBS), sterile tap water, normal saline, and Ringer's lactate on wound healing in an in vitro model.
Study Design —The effects of PBS, sterile tap water, normal saline, and Ringer's lactate on a primary line of canine embryonic fibroblasts were determined.
Animals or Sample Population —A primary line of canine embryonic fibroblasts.
Methods —The effects of the various lavage solutions were determined by (1) vital staining of the treated cells with a 0.5% trypan blue solution, (2) evaluation of the amount of lactate dehydrogenase released by the treated cells, and (3) cytopathologic evaluation of hematoxylin and eosin-stained monolayers of treated canine fibroblasts. The cells were exposed to the lavage treatments for the following time intervals: 0.5 minute, 1 minute, 2.5 minutes, 5 minutes, and 10 minutes. PBS was used as the control.
Results —Sterile tap water significantly damaged canine fibroblasts at all time intervals ( P = .05). This was attributed to the alkaline pH, hypotonicity, and presence of numerous cytotoxic trace elements in the tap water used. Cytotoxic effects were noted in fibroblasts after 10 minutes' exposure to normal saline; this may be because of the acidic pH of normal saline and lack of a buffering system. Ringer's lactate did not induce any significant fibroblast injury.
Conclusions —PBS and Ringer's lactate do not induce any significant fibroblast injury, whereas normal saline and sterile tap water cause mild and severe cytotoxic effects in vitro.
Clinical Relevance —Further clinical investigation is indicated to establish whether Ringer's lactate is the wound lavage solution of choice compared with normal saline. Sterile tap water may cause considerable fibroblast injury.     

畜禽体外培养细胞生长规律研究

本研究利用组织块贴壁培养法对鲁西黄牛、蒙古马、北京鸭和狼山鸡等4个品种体外培养细胞的生长、分化规律进行了研究。通过绘制其生长曲线和在激光共聚焦显微镜下拍摄细胞生长过程,初步分析成纤维细胞的生长、分化规律。试验结果表明,4个品种的细胞生长曲线均呈明显的“S”形,家畜和家禽的细胞潜伏期和停滞期的长短以及细胞群体倍增时间均有明显差异,蒙古马和狼山鸡体外培养细胞的单个细胞分裂期也有显著差异,蒙古马为97 min,而狼山鸡为85 min。本试验构建的4个品种成纤维细胞系不仅使畜禽遗传资源在细胞水平永久保存下来,而且为分子生物学研究提供宝贵材料。     

An Experimental Trial of Oxytetracycline as a Therapy for Black Spermatophore Disease in Penaeus vannamei

Abstract

The efficacy of oxytetracycline was assessed as a potential therapy for male reproductive tract syndrome in a population of 160 previously affected, pond-reared, adult Penaeus vannamei. All animals were individually tagged, and the severity of disease was assessed grossly 2 weeks before, during, and 4 weeks after feed medicated with oxytetracycline hydrochloride was administered. Bacterial cultures indicated that more Vibrio sp. were isolated from animals with melanized spermatophores than from animals with normal spermatophores at the same site. Vibrio alginolyticus was the most common bacterial isolate, and the bacterial isolates were sensitive to oxytetracycline. A t-test analysis of the mean lesion severity scores showed no significant difference between the control animals and animals that received the medicated feed. A significant difference in severity scores among designated severity groups (low, medium, high; P < 0.01) was maintained throughout the experiment. Overall, the trend in all severity groups was a gradual increase in severity over time. These results suggest that this case of male reproductive tract syndrome was not responsive to oxytetracycline therapy. In addition, these results provide further evidence of a noninfectious primary etiology.     

An In Vitro Comparison of the Holding Strength of Partially Threaded vs Nonthreaded Intramedullary Pins

The pin holding strengths of partially threaded and nonthreaded intramedullary pins were compared in an in vitro study. The mean percent holding strength of partially threaded pins to nonthreaded pins was 102%. No relationships could be determined when the holding strength of the pins was evaluated as a function of the dog's weight, bone length, and length of pin within the bone. It was concluded that no statistical difference in in vitro pin holding strength exists between the two types of pins.     

Immunisation against ovine caseous lymphadenitis: comparison of Corynebacterium pseudotuberculosis vaccines with and without bacterial cells

Sheep were immunised with Corynebacterium pseudotuberculosis vaccines prepared from cell-free toxoid or from toxoid with formalin-killed cells of C pseudotuberculosis added. Resistance of sheep to infection was tested 6 months after immunisation by inoculation with caseous lymphadenitis pus. The outcome was assessed 3 months later by slaughter and inspection of the sheep for lesions of caseous lymphadenitis. immunised sheep were adequately protected against infection as shown by a significant reduction in the number of sheep exhibiting lesions compared with control sheep, and by fewer abscesses in affected vaccinated sheep than in affected control sheep. The protective potency of the vaccines was not improved by the inclusion of cells of C pseudotuberculosis.     

Immunisation of goats against contagious caprine pleuropneumonia using sonicated antigens of F-38 strain of mycoplasma

Three groups of 15 goats each were immunised against contagious caprine pleuropneumonia (CCPP) using sonicated antigens of the F-38 strain of mycoplasma incorporated in incomplete Freund's adjuvant (IFA), emulsified in aluminium hydroxide and phosphate buffered saline respectively. Three months after immunisation, five goats from each group were challenged by the in-contact method. The goats immunised with the antigen incorporated in IFA were all solidly immune to the challenge whereas only two of five of the goats in the other two groups were protected. When the remaining 10 animals from each group were challenged six months after immunisation, those immunised with the antigen in IFA were still solidly immune while only two goats from each of the other two groups were protected. These results show that effective immunity against CCPP caused by the F-38 strain can be induced by vaccination with sonicated F-38 antigens emulsified in IFA.     

朊·病·毒·蛋·白·体·外·转·化

朊病毒疾病，包括新型变异型克雅氏病（vCJD）、牛海绵状脑病（BSE）、鹿慢性消耗性疾病（CWD）和羊痒病等，都属于神经退行性疾病。这种难以灭活并且不含常规核酸的非传统性病原体被命名为朊病毒。朊病毒由错误折叠的PrP^Sc（Proteinase-resistant Protein）组成，并通过一个自我繁殖过程诱导宿主编码的糖蛋白PrP^c（Cellular Prion Protein）经过一种构象改变形成新的PrP^Sc分子。     

An In Vitro Biomechanical Investigation of the Mechanical Properties of Dynamic Compression Plated Osteotomized Adult Equine Tibiae

Objective — To determine the monotonic mechanical properties of osteotomized adult equine tibiae stabilized with two dynamic compression plates (DCP) and to compare the mechanical properties with those of intact tibiae and in vivo loads.
Study Design — The compressive, bending, and torsional mechanical properties of plated and intact tibiae were assessed in vitro.
Animals or Sample Population — Twelve pairs of adult equine tibiae.
Methods — Tibiae were loaded in axial compression, craniocaudal 3-point bending, or torsion in external rotation in a single cycle to failure. Mechanical properties were determined from load-displacement data.
Results — Compared to intact tibiae, the mean yield load, failure load and stiffness of plated tibiae were significantly lower ( P <.05) (compression and torsion); and the mean yield and failure bending moments, and bending stiffness, of the plated tibiae were lower ( P <.075 for yield), or significantly lower, respectively. The mean compression and bending yield loads for plated tibiae were greater than in vivo loads. The mean torsional yield load for plated tibiae approximated the torsional load determined for the adult horse at a walk.
Conclusions — Simple, anatomically reduced, DCP plated tibiae should have adequate strength to withstand immediate, postoperative in vivo compressive loads and bending moments placed on the tibia in vivo during immediate postoperative activities, however, may not have adequate torsional strength during immediate postoperative weight-bearing at a walk.
Clinical Relevance — Additional supportive methods, to decrease torsional loads, may be beneficial in maintaining stability of plate repaired tibiae during recovery from anesthesia and postoperative healing.