AE油佐剂灭活疫苗对鸡胚和仔鸡的保护力试验研究

用三批AE（Avian Encephalomyelitis）油佐剂灭活疫苗免疫开产前种鸡，免疫后定期采集种蛋进行孵化，当孵至6日龄时取部分鸡胚，卵黄囊途径接种AEV VR株，进行鸡胚AE易感性试验，余鸡胚孵化出雏，分别为1、7、14、21日龄雏鸡采用肌肉途径攻击AEV VR株，攻毒后观察不同日龄仔代雏鸡AE的保护能力。结果疫苗免疫后2－3个月的种鸡所产种蛋的鸡胚AE易感性试验的保护率达100％，而同期所产种蛋孵出的仔代雏鸡，在出雏后3周内对AEV工VR株攻毒的保护率亦达100％，免疫后6－7个月种鸡所产种蛋的鸡胚AEV VR易感性试验的保护率达75％－805，而同期所产种蛋孵出的仔代雏鸡，在出雏后3周内对AEV VR株攻毒的保护率达70－90％。试验结果表明，鸡胚AE易感笥试验的鸡胚保护率与同批种蛋孵出雏鸡对AEV VR肌肉途径攻毒的保护率基本相同。     

AE油佐剂灭活疫苗对鸡胚和仔鸡免疫保护力试验观察

用 3批AE (AvianEncephalomyelitis)油佐剂灭活疫苗免疫开产前种鸡 ,免疫后定期采集种蛋进行孵化。当孵至 6日龄时取部分鸡胚 ,卵黄囊途径接种AEVVR株 ,进行AE鸡胚易感性试验。剩余鸡胚孵化至出雏后 ,分别于 1 ,7,1 4 ,2 1日龄肌肉注射AEVVR株攻毒。攻毒后观察不同日龄子代雏鸡AE的保护能力。结果疫苗免疫后 2～ 3个月的种鸡所产种蛋胚对AEV保护率达 1 0 0 % ,而同期所产种蛋孵出的子代雏鸡 ,在出雏后 3周内对AEVVR株攻毒的保护率亦达 1 0 0 %。免疫后 6～ 7个月种鸡所产种蛋胚对AEVVR保护率达 75 %～ 80 % ,而同期所产种蛋孵出的子代雏鸡 ,在出雏后 3周内对AEVVR株攻毒的保护率达 70 %～ 90 %。试验结果表明 ,AE鸡胚易感性试验的鸡胚保护率与同期雏鸡对AEVVR肌肉注射攻毒的保护率基本相同     

AE油佐剂灭活疫苗对鸡胚和仔鸡的保护力试验

三批禽脑脊髓炎(AE)油佐剂灭活疫苗免疫开产前种鸡,种鸡免疫2～3个月后所产种蛋对禽脑脊髓炎病毒(AEV)鸡胚易感性试验的受保护率达100%,而同期所产种蛋孵出的仔代雏鸡,在出雏后3周内对AEVVR株攻毒的受保护率亦达100%;种鸡免疫6～7个月后所产种蛋对AEVVR鸡胚易感性试验的受保护率达75%～80%,而同期所产种蛋孵出的仔代雏鸡,在出雏后3周内对AEVVR株攻毒的受保护率达70%～90%。试验结果表明,AE灭活疫苗对AEV鸡胚易感性试验的鸡胚保护率与同期雏鸡对AEVVR肌肉途径攻毒的保护率基本相同。     

AE油佐剂灭活疫苗对鸡胚和仔鸡的保护力试验

三批禽脑脊髓炎(AE)油佐剂灭活疫苗免疫开产前种鸡,种鸡免疫2~3个月后所产种蛋对禽脑脊髓炎病毒(AEV)鸡胚易感性试验的受保护率达100%,而同期所产种蛋孵出的仔代雏鸡,在出雏后3周内对AEV VR株攻毒的受保护率亦达100%; 种鸡免疫6~7个月后所产种蛋对AEV VR鸡胚易感性试验的受保护率达75%~80%,而同期所产种蛋孵出的仔代雏鸡,在出雏后3周内对AEVVR株攻毒的受保护率达70%~90%。试验结果表明,AE灭活疫苗AEV鸡胚易感性试验的鸡胚保护率与同期雏鸡对AEV VR肌肉途径攻毒的保护率基本相同。     

AE油佐剂灭活度苗对鸡胚和仔鸡的保护力试验

三批禽脑脊髓炎(AE)油佐剂灭活疫苗免疫开产前种鸡，种鸡免疫2～3个月后所产种蛋对禽脑脊髓炎病毒(AEV)鸡胚易感性试验的受保护率达100％，而同期所产种蛋孵出的仔代雏鸡，在出雏后3周内对AEVVR株攻毒的受保护率亦达100％；种鸡免疫6～7个月后所产种蛋对AEVVR鸡胚易感性试验的受保护率达75％～80％，而同期所产种蛋孵出的仔代雏鸡，在出雏后3周内对AEVVR株攻毒的受保护率达70％～90％。试验结果表明，AE灭活疫苗对AEV鸡胚易感性试验的鸡胚保护率与同期雏鸡对AEVVR肌肉途径攻毒的保护率基本相同。     

禽脑脊髓炎弱毒疫苗不同免疫期的种鸡及其后裔雏鸡母源抗体的衰减规律

艾维菌父母代肉种鸡经禽脑脊髓炎病毒(AEV)弱毒疫苗免疫后，用琼脂扩散试验对不同免疫期种鸡的后裔雏鸡的母源抗体进行动态监测。结果发现，26周龄种鸡禽脑脊髓炎(AE)抗体阳性率为86．79／6～1009／6．其后裔雏鸡在1～7日龄时母源抗体阳性率为83．3％～100％；14日龄时降至30．0％～70．09／6；多数在21日龄时转阴。36周龄种鸡AE抗体阳性率为56．7％～76．79／6，其后裔雏鸡在1日龄时母源抗体阳性率只有50．0％～76．7％；7日龄时降至10．0％～50．0％；14日龄时全部转阴。表明，雏鸡AE母源抗体水平及其衰减规律受种鸡抗体水平的影响。攻毒保护试验发现，低母源抗体雏鸡(1日龄母源抗体阳性率为50．0％)，不但7～28日龄脑内攻毒后6～11d全部发病，而且14日龄颈部皮下攻毒后11～13d也有6／10雏鸡发病；而高母源抗体雏鸡(1日龄的母源抗体为1009／6)，虽然14～28日龄对脑内攻毒易感，但是颈部皮下攻毒后观察45d均未发病。证实，雏鸡1日龄的AE母源抗体为50．0％时，很难保护其免受AEV的侵袭。     

禽脑脊髓炎活疫苗免疫持续期试验

将200009批疫苗分三个剂量组（Ⅰ，Ⅱ，Ⅲ），病毒含量分别为每羽份合500、1000、1500EID50，口服免疫13周龄SPF鸡，同时设进口同类疫苗组（Ⅳ）和未接种空白组（Ⅴ）作为对照。，分别于免疫后7d、14d、17d、21d、28d、42d、56d、70d、84d、105d、126d、149d、169dR血，分离血清，采用IDEXX禽脑脊髓炎抗体检测ELISA试剂盒检测血清中AEV抗体水平，并通过鸡胚易感试验和后代雏鸡试验评价产蛋后鸡群的免疫状态。结果表明，疫苗接种后14d，免疫鸡血清已全部阳转，免后42d时抗体出现第一个峰值，此后一直保持较高水平，并且抗体水平的高低与接种疫苗的病毒含量呈正相关关系。用AEVVR强毒进行的鸡胚易感试验，免后6～55周免疫组鸡胚的感染率在35％以下；后代雏鸡攻毒保护率在92．9％以上。     

不同IBD疫苗对IBDV超强毒株NN1172感染的免疫保护试验

为了评估不同传染性法氏囊病疫苗对广西地方品种鸡的免疫保护效果,试验将1日龄后备种鸡分成4组,分别用A、B、C三种商品疫苗对Ⅰ、Ⅱ、Ⅲ组鸡接种免疫,Ⅳ组鸡在C疫苗免疫的基础上于14日龄用D疫苗进行第二次免疫。在免疫前(1日龄)及免疫后的第7,14,21,28,35,42,49,56日龄每组分别采集血清30份,进行传染性法氏囊病病毒(IBDV)抗体的测定;Ⅰ、Ⅱ、Ⅲ组鸡在21日龄,Ⅳ组鸡于28日龄分别用IBDV超强毒地方分离株NN1172进行攻毒,并分别在攻毒后的3,7,10天观察各组雏鸡的临床症状、死亡情况、发病鸡剖检病变,统计免疫保护率。结果表明:各免疫组雏鸡抗体滴度均呈现先降再升的趋势,其中Ⅳ组在免疫后期呈现比较平稳的上升趋势;免疫攻毒保护率结果表明,Ⅱ组的保护率最低(73.3%,11/15),Ⅰ、Ⅲ组均为80%(12/15),Ⅳ组保护率最好(86.7%,13/15)。说明不同疫苗对广西地方品种鸡免疫效果存在一定差异,而二次免疫可以对雏鸡提供更好的免疫保护。     

禽脑脊髓炎病毒VR株的致病性研究

为探索禽脑脊髓炎病毒强毒VR株对SPF鸡的致病性,开展了不同接种途径和不同日龄SPF鸡的致病力试验。不同接种途径致病力试验结果表明,AEV VR株口服后不能引起发病;刺种、肌肉注射途径接种随着日龄增大,发病率降低;脑内注射途径接种可引起试验鸡全部发病。最小致病量试验结果显示,VR株脑内注射攻毒的最小致病量为10~(2.0) EID_(50)。不同日龄SPF鸡的致病力试验结果表明,随着试验鸡日龄的增大,其致病力略有差异,日龄越小,发病率越高。结果表明,AEV VR株脑内攻毒70日龄内SPF鸡的发病率为80%及以上,攻毒剂量为10~(4.0)EID_(50)。     

1株基因3型鸭甲肝病毒鸡胚化弱毒株的培育

为研发基因3型鸭甲肝病毒(Duckhepatitis virustype3,DHAV-3)的弱毒活疫苗,用SPF鸡胚对DHAV-3Y株进行了连续传代致弱,由此获得第80代鸡胚适应毒。致病性试验结果显示,第80代毒株对1日龄雏鸭已无致病性。免疫攻毒保护试验显示,雏鸭在1日龄时经肌肉注射途径免疫第80代鸡胚适应毒,能有效抵抗7日龄时的强毒感染,保护指数为100%。表明第80代鸡胚适应毒是一株具有良好免疫原性的鸡胚化弱毒疫苗候选株。     

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