肉用鸡成髓细胞白血病

在过去的3年内,肉用种鸡群中的成年鸡成髓细胞白血病(myeloidleukosis)(或称骨髓细胞瘤,myelcytomatosis)(ML)使世界范围内的禽肉加工业遭受了严重损失。本病是由一种有囊膜的病毒引起的,这种病毒属于禽白血病病毒(avianleukosisvirus,ALV)的一个新亚群,即J群,通常称之为ALV-J。70年代后期和80年代,ML病例在英国的商品代肉鸡中散在发生,但未达到引起人们重视的程度。一般来说,由ALV引起的白血病对于肉用型鸡并不是一个重要的疾病。事实上许多肉鸡品种似乎对通常ALV亚群病毒有遗传抵抗力。1988年,在研究肉用种鸡的ALV感染状况时,从…     

抗J亚群禽白血病病毒囊膜糖蛋白特异性单克隆抗体的研制及其特性

J亚群禽白血病病毒（ALV-J）是一种主要感染肉用型鸡的反转录病毒。本研究用表达ALV-J囊膜蛋白基因产物的Sf9细胞免疫Balb/c小鼠，取其脾脏细胞与骨髓瘤细胞NS1进行融合，获得了4株特异性抗ALV-J的单克隆抗体。免疫荧光分析结果表明，3株单克隆抗体仅与所试验的ALV-J毒株反应，而不能与ALV的A、B、C、D和E亚群的毒株反应。有趣的是，有一株单克隆抗体可以与所有试验的外源性ALV毒株反应，但不与内源性的E亚群反应。Western Blot和免疫沉淀试验结果表明，单克隆抗体识别的ALV-J囊膜糖蛋白的分子量为90-94kD，识别未糖基化的囊膜蛋白分子量约为53kD。用这些单克隆抗体能检测出ALV-J病毒感染鸡胚成纤维细胞中的病毒抗原。这些结果提示这些单克隆抗体可用于ALV-J疾病的诊断和流行病学调查。     

J亚群禽白血病研究进展

J亚群禽白血病病毒是上世纪90年代初从商品代肉鸡中分离鉴定出来的新的ALV亚群,主要引起肉鸡的骨髓瘤白血病(myloid leucosis,ML)。2009年,J亚群禽白血病在我国呈高发态势。我国于1999年首先在肉用型鸡群分离鉴定出ALV-J的中国株,随后相关研究依次展开。论文就ALV-J的流行病学、检测方法、病毒变异、免疫抑制及与其他免疫抑制疾病共感染等几个方面进行了简要介绍。     

祖代肉用鸡群禽白血病病毒感染的实验室诊断

对疑似J亚群禽白血病病毒（ALV－J）感染的祖代肉用型种鸡群进行病原微生物学的实验室诊断。组织病理学检测结果表明，病鸡脾、肾病理组织切片上有大量增生的髓细胞，呈典型的髓细胞瘤病理显微变化。肾组织触片和组织切片用抗ALV－J特异性单克隆抗体G2进行间接免疫荧光反应（IFA）检测，结果呈阳性。病料接种鸡胚成纤维细胞（CEF）盲传3代后，分离到1株病毒（JS－Nt），经鉴定为ALV－J。这些结果证明该鸡群存在ALV－J的感染。     

鸡J亚群白血病的诊断与控制

经典的禽白血病病毒(ALV)可被划分为A、B、C、D和E5个亚群，A、B、C和D亚群是外源性的白血病病毒，而E亚群则主要以前病毒的形式而无处不在。经过多年的努力，到80年代中期，世界发达国家已基本上消除了这类经典的外源性白血病病毒的感染。在1988年，英国的Payne等人从肉用型鸡群中分离出一株新的ALV，根据病毒感染宿主的范围，病毒干扰及交叉中和试验等确定这是一类新的ALV，称之为J亚群(ALV-J)。短短十几年间，该病毒迅速传播到世界各地，我国在1999年由杜岩等人从市场上的商品代肉鸡中分离检测到ALV-J。本文就临床症状、流行病学、病理学诊断、免疫学检查和综合防治措施等方面介绍了J亚群白血病的诊断与防治。     

华东地区蛋鸡群中禽白血病的分子流行病学调查

为了解华东地区蛋鸡群中禽白血病的流行情况,2011年3月至2012年10月,从江苏、山东、安徽、上海等省市的蛋鸡养殖场中采集疑似禽白血病病例样品105份,经DF-1细胞分离培养、间接免疫荧光试验鉴定,从中分离禽白血病病毒(ALV)15株,继而对分离毒株gp85基因进行了序列测定和遗传进化分析。结果表明,在所获得的ALV分离株中,有A亚群ALV(ALV-A)3株,B亚群ALV(ALV-B)4株,剩余8株则均为J亚群ALV(ALV-J)。ALV-A、ALVB分离株遗传进化较为稳定,与其原型株(RAV-1、RAV-2)gp85基因核苷酸序列同源性均在98%以上,与我国近年来的地方分离株亲缘关系较远。ALV-J分离株与其原型株(HPRS-103)gp85基因核苷酸序列的同源性在92.8%~94.5%之间。8株ALV-J分离株中,只有1株与蛋鸡ALV-J分离株有较高的亲缘关系,其余均较远,反而与早期的肉鸡分离株有较高的亲缘关系,表明目前于华东地区蛋鸡群中流行的ALV-J可能来源于早期肉鸡分离株的感染。4株ALV-J分离株与我国地方品系HR土鸡的ALV-J分离株HR332J具有很高的亲缘关系,表明ALV-J的感染范围进一步扩大,对地方品系鸡也造成了很大的危害。     

地方品系鸡中一株A亚群鸡白血病病毒的分离和鉴定

将种蛋孵化到9～11 d,分别制备成鸡胚成纤维细胞(chicken fibroblast cells,CEF)培养,再将其细胞上清接种对内源性白血病病毒(avian leukosis virus,ALV)有抵抗力的DF1细胞,从山东某地方品系种蛋中分离到一株外源性ALV,SDAU09E1.用PCR扩增其囊膜蛋白基因(env)并隆测序后,将其gp85序列与已发表的各亚群ALV比较分析表明,该毒株与A亚群6个毒株同源性最高,为89.1%～90.9%,而与已发表的鸡的A、C、D、E亚群ALV的gp85的同源性仅在73.2%～87.9%之间,与目前国内最常见的J亚群的gp85的同源性更是低至30.3%～32.4%.这是我国地方品系鸡群中第一次分离和鉴定出ALV-A及其gp85基因.     

2009年湖北省鸡J亚群白血病的初步调查分析

禽白血病(avian leukosis,AL)是由反转录病毒科甲型反转录病毒属禽反转录病毒(avian leukosis virus,ALV)引起的以禽类造血组织中某些细胞成分增生为主的各种可传染的肿瘤疾病.根据病毒中和试验宿主范围和囊膜糖蛋白的特性及其它一系列标准,将禽白血病/肉瘤群病毒划分为A到J 10个亚群,其中分离自鸡的有6个亚群(A、B、C、D、E、J).鸡J亚群白血病病毒(ALV-J)是1988年Payne等[1,2]首次从商品代肉用鸡中分离到并鉴定出的鸡白血病病毒的一个新亚群.     

J、K亚群禽白血病病毒的分离和囊膜蛋白(gp85)基因序列分析

为了解现阶段我国禽白血病病毒(ALV)的流行特征和演化趋势,本试验于2021—2022年从国内某鸡场采集蛋清ALV衣壳蛋白(p27)抗原阳性的鸡血浆,接种鸡胚成纤维细胞(DF-1)分离病毒并进行亚群鉴定;采用聚合酶链式反应(PCR)技术扩增分离株的囊膜蛋白(gp85)基因片段,并对其进行测序,将基因序列与ALV不同亚群毒株进行比对和遗传进化分析;选取氨基酸变化差异较大的分离毒株进行间接免疫荧光鉴定。结果显示,共分离到7株ALV毒株(3株J亚群,4株K亚群),ALV-J分离毒株CAU4932、CAU4860和CAU2259的gp85基因片段长度为918 bp,编码306个氨基酸,分离毒株之间gp85基因核苷酸同源性为90.5%～95.2%,gp85蛋白氨基酸同源性为95.1%～99.3%;ALV-K分离毒株CAU7049、CAU5006、CAU7176和CAU7168的gp85基因片段长度为1 008 bp,编码336个氨基酸,分离毒株之间gp85基因核苷酸同源性为89.4%～92.3%,gp85蛋白氨基酸同源性为94.0%～99.7%。gp85蛋白氨基酸序列同源性比对发现,分离株gp8...     

一株新亚群禽白血病病毒全基因组序列分析

为了解外源性禽白血病病毒(ALV)在山东省部分地区肉鸡中的流行状况,采集无菌抗凝血分离血浆接种DF-1细胞、ELISA p27抗原检测以及DNA提取进行PCR扩增等方法,从山东省某地区大型养殖场不同个体养殖场出栏肉鸡群中分离鉴定出1株ALV,命名为FC1505。分析其囊膜糖蛋白gp85氨基酸序列与近年来从地方品种鸡中疑似新亚群ALV-K分离株的相似性最高,相似性均在95%以上,而与其他已知亚群ALV的相似性均低于90%。为了进一步分析该分离株分子特性,对其进行全基因组测序,并与已知亚群ALV分离株序列进行比较。结果表明,FC1505分离株整个基因组中gag、pol和gp37基因相对保守,与ALV参考毒株序列相似性都在90%以上,但均与疑似K亚群的ALV分离株相似性最高;全基因组序列分析进一步说明FC1505属于ALV-K。本研究继我国江苏省和华南地区K亚群ALV报道后,首次从山东地区肉鸡中鉴定到一株ALV-K并完成其全基因组序列分析。     

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.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

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

Tropical Animal Health and Production -