仔猪水肿病蜂胶佐剂多价灭活苗的研制Ⅱ免疫保护期和疫苗保存期试验

对仔猪水肿病蜂胶佐剂多价灭活苗进行了免疫产生期、免疫持续期和疫苗保存期试验。研究表明 :仔猪接种该疫苗 5～ 7d后便产生免疫力 ,到第 9天时抗体产生水平已经很高 ;以免疫仔猪攻毒后的存活率不低于 95%为标准 ,疫苗的免疫持续期可达 9个月以上 ;以物理性状合格和免疫仔猪攻毒后的存活率不低于95%为标准 ,疫苗置 4℃时保存期为 1 8个月 ,2 5℃保存 9个月为宜     

鸡大肠杆菌病多价灭活苗的研制

采用自行分离和鉴定的大肠杆菌按适当的比例制备了大肠杆菌多价灭活苗。经免疫期、保存期,菌苗接种5 d后开始产生免疫,至7 d~9 d免疫力已很坚强;从免疫持续期试验结果看,菌苗免疫后7 个月,攻毒保护率不低于90%;接种后10 个月,攻毒保护率也不低于70%;疫苗置4 ℃和25 ℃贮藏,保存期分别达18个月和6个月。     

鸡新城疫病毒B_(95)株免疫研究

本试验采用鸡胚增殖培养鸡新城疫B95 株病毒。经对培养的尿囊液病毒价达EID50 107.75。无菌性检验和安全性检验均符合疫苗要求 ,将其选作试验用疫苗进行了试验。结果表明 ,该苗滴鼻点眼免疫的最小剂量为105.75,拌料免疫最小剂量为106.75。以B95 株疫苗滴鼻点眼免疫的鸡 ,在免疫后5天时就可产生坚强的免疫力 ,免疫期可达4个月。同居接触免疫鸡能获得了良好的免疫效果 ,攻毒总保护率与滴鼻点眼免疫差异不显著。拌料免疫效果良好 ,与NDV滴鼻点眼免疫差异不显著。B95 株苗在0～4℃条件下保存4个月 ,免疫攻毒保护率达80% ;在室温下保存2个月 ,免疫攻毒保护率达100%。     

鸡新城疫病毒B95株免疫研究

本试验采用鸡胚增殖培养鸡新城疫B95株病毒，经对培养的尿囊液病毒价达EID5010^7.75。无菌性检验和安全性检验均符合疫苗要求，将其选作试验用疫苗进行了试验，结果表明，该苗滴鼻点眼免疫的最小剂量为10^5.75，拌料免疫最小剂量为10^6.75，以B95株疫苗滴鼻点眼免疫的鸡，在免疫后5天时就可产生坚强的免疫力，免疫期可达4个月，同居接触免疫鸡能获得了良好的免疫效果，攻毒总保护率与滴鼻点眼免疫差异不显著，拌料免疫效果良好，与NDV滴鼻点眼免疫差异不显著，B95株苗在0－4℃条件下保存4个月，免疫攻毒保护率达80％，在室温下保存2个月，免疫攻毒保护率达100％。     

鸡传染性鼻炎(三价)和新城疫二联灭活疫苗的研究

利用Page A型、B型、C型副鸡禽杆菌和新城疫病毒La Sota株,研制鸡传染性鼻炎(三价)和新城疫二联油乳剂灭活疫苗。用3个批次疫苗进行单剂量(0.5mL/次)3次接种和大剂量(2.0mL)单次接种的安全性试验、SPF鸡的免疫效力试验、商品鸡的免疫持续期试验和疫苗的保存期试验。结果表明,3批疫苗对试验鸡安全无副作用;免疫接种SPF鸡只30d后对A、B、C型副鸡禽杆菌攻毒的保护率≥80%,用20μL/只疫苗免疫接种SPF鸡21d后新城疫的平均HI抗体24;商品鸡42日龄首免,110日龄二免,二免后9个月对A、B、C型副鸡禽杆菌攻毒的保护率≥70%,对新城疫病毒强毒100%保护;用4℃~8℃保存12个月和15个月的3批疫苗进行了SPF鸡的近期免疫效力试验,结果对A、B、C型副鸡禽杆菌攻毒的保护率≥70%,用20μL/只疫苗免疫SPF鸡,免疫接种后21d新城疫病毒的平均HI抗体24,对新城疫病毒强毒的攻毒保护率70%。说明研制的疫苗安全有效。     

猪传染性胸膜肺炎三价灭活疫苗的研究——效力、最小免疫量、免疫持续期和保存期试验

对中国农业科学院兰州兽医研究所研制的8批猪传染性胸膜肺炎三价灭活疫苗进行了效力试验，并对其中的3批疫苗进行了最小免疫量，免疫持续期和保存期试验。结果表明，免疫猪对APP（Actinobacillus pleuropneumoniae)1,3,7血清型强毒攻击的近期保护率分别为91．6％，91．6％ 95．8％；免疫剂量为1mL时，对APP1，3，7血清型强毒攻击的保护率分别为33．3％，33．3％和50．0％；免疫剂量为2mL时，保护率分别为88．9％，88．9％和100％；免疫剂量为3mL或4mL时，保护率均为100％，免疫后120d和180d时，攻毒保护率分别为100％，88．9％，100％和88．9％，77．8％，100．％；疫苗经4－8℃保存180d和360d后，攻毒保护率分别为88．9％，100％，100％和100％，77．8％，88．9％。     

猪伪狂犬病病毒基因缺失灭活疫苗（LA-A株）的最小免疫剂量和制品保存期的研究

本研究将伪狂犬病病毒(Pseudorabies virus,PRV)变异株(PRV AH02LA株)的gE基因缺失株(LA-A株)接种BHK-21细胞,经纯悬浮培养制备抗原,甲醛灭活后制备油乳剂灭活疫苗,并确定该灭活疫苗的最小免疫剂量和效力检验方法,以及在2~8℃保存期。结果显示:猪伪狂犬病病毒基因缺失灭活疫苗(LA-A株)的效力检验方法为以2.0 mL(抗原含量108.20TCID50)接种4~5周龄PRV阴性健康仔猪,颈部肌肉注射,间隔28 d以相同剂量和方法加强免疫,加强免疫后第21 d,免疫猪血清PRV抗体中和指数应不低于10000,攻毒保护率应不低于80%;最小免疫剂量为1.0 mL(抗原含量107.90 TCID50);制品保存期:在2~8℃保存期为18个月。该研究结果为新型疫苗的研制提供了重要的试验依据。     

鸡传染性法氏囊病免疫复合物疫苗的安全性和免疫效力试验

用鸡法氏囊病免疫复合疫苗(IBDV-Icx)和常规IBD活疫苗分别免疫1日龄商品鸡和SPF鸡,进行疫苗的安全性及免疫效力比较.免疫后8d检测,IBDV-Icx免疫组鸡的法氏囊未见明显萎缩,而传统弱毒疫苗免疫组鸡的法氏囊萎缩明显;免疫后28d各组用IBDV标准强毒株进行攻击,IBDV-Icx免疫组鸡的攻毒保护率均为10/10,常规IBD活疫苗对照组分别为8/10及9/10.免疫后3个月,IBDV-Icx免疫组血清抗体可达AGP1∶32,攻击强毒仍为10/10保护,而常规IBD活疫苗免疫后2个月抗体AGP为0,攻毒保护率为1/10,免疫后3个月时攻毒10/10发病.     

小鹅瘟病毒卵黄抗体被动免疫期研究

本实验取3批实验室试制的卵黄抗体,琼扩效价为1∶16,按0.5 m L/只接种1、3日龄易感雏鹅,分别在注射抗体后1、3、5和7日攻毒,观察攻毒保护情况。结果显示:1日龄雏鹅注射抗体后1日攻毒保护率为96.67%,3日攻毒保护率为100%,5日攻毒保护率为86.67%,7日攻毒保护率为76.67%;3日龄雏鹅注射抗体后1日攻毒保护率为100%,3日攻毒保护率为96.67%,5日攻毒保护率为86.67%,7日攻毒保护率为80%。以免疫攻毒保护率不低于80%为标准,本研究确定小鹅瘟病毒卵黄抗体的被动免疫保护期为5日,随着时间的延长,保护作用逐渐减弱。     

牛病毒性腹泻病毒弱毒活疫苗免疫持续期的研究

为检测牛病毒性腹泻病毒(BVDV)弱毒活疫苗在免疫牛体内抗体产生及其消长规律,评价弱毒疫苗的保护效力,并确定免疫持续期,本试验对免疫试验牛每头颈部肌肉接种BVDV SM株弱毒疫苗104.5TCID50,监测血清抗体效价,进行免疫持续期的确定。在疫苗免疫后的6个月、9个月和12个月,分别抽取5头免疫组和5头对照组牛,采用BVDV-JL强毒株进行攻毒试验,每头牛攻毒剂量为6×107.0TCID50/mL。结果显示疫苗免疫后12个月时血清中和抗体效价仍维持在1∶1048以上。攻毒结果显示,在3个不同时间点进行强毒攻击后,免疫组所有动物白细胞数量都没有下降也没有分离到病毒,而对照组动物白细胞数下降均超过30%,6个月和9个月时动物血清中均能分离到病毒,而12个月对照组动物由于年龄大,没有分离到病毒,因此暂定此疫苗的免疫持续期为9个月。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein