安卡鸡TLR4基因外显子2多态性及其与经济性状的关联分析

研究采用PCR-SSCP对安卡鸡TLR4基因外显子2多态性进行检测,并分析其多态性对经济性状的影响。结果表明:安卡鸡TLR4基因存在AA、AB和BB 3种基因型,基因型频率分别为0.3143、0.4000和0.2857,等位基因A、B的频率分别为0.5143和0.4857。χ2适合性检验表明,安卡鸡TLR4基因外显子2等位基因的分布处于Hardy-Weinberg平衡状态。序列分析结果显示,TLR4基因外显子2的114 bp和142 bp处各有1个G/A突变,G114A为沉默突变,没有引起氨基酸改变,G142A为错义突变,氨基酸由谷氨酸转变为赖氨酸。分析这3种基因型与安卡鸡一些重要经济性状间的关联性,表明,3种基因型个体间的生长发育性状、屠宰性状以及常规肉质等重要经济指标差异不显著,安卡鸡TLR4基因外显子2对重要经济性状没有显著的影响。     

草原红牛MSTN基因第一外显子SNPs多态性分析

根据牛的肌肉生长抑制素基因（myostatin,简写为MSTN）外显子1的序列设计引物,用PCR—SSCP方法对草原红牛和利木赞与草原红牛的杂交牛进行了单核苷酸多态性分析,并检测到了多态性,表现为从、BB和AB3种基因型。对两种纯合子进行测序,结果发现282位碱基发生突变,由C突变为A,导致编码的氨基酸由苯丙氨酸变为亮氨酸。经独立性检验发现基因频率和基因型频率的分布与含利木赞血液的多少有关;并通过不同性状在该位点不同基因型间的显著性检验表明,等位基因B可以显著的提高草原红牛的日增重、屠宰率、净肉率和肉骨比。     

鸡NRAMP1蛋白序列特征、分子进化与突变分析

为解析鸡天然抗性相关巨噬蛋白1(Natural-resistance-associated macrophage protein 1,NRAMP1)223位Arg突变为Gln对蛋白质结构和理化性质的影响，试验系统分析了鸡NRAMP1蛋白质结构特征，重点比较鸡NRAMP1 223位Arg（抗性）和Gln（易感）的蛋白质理化性质和结构差异，并分析略阳乌鸡NRAMP1基因该位点的多态性。结果表明，NRAMP1蛋白质保守性较高，鸡和人NRAMP1氨基酸序列相似度达68%，以鸡NRAMP1的第223位氨基酸为参考，其他物种该位点均为碱性氨基酸（Arg、Lys、His）；鸡NRAMP1第2 454位G突变为A,223位Arg变成Gln，其理化性质和二、三级结构均发生变化，该位点附近的β-转角变为α-螺旋。略阳乌鸡NRAMP1基因该位点的GG基因型频率为67.1%,GA频率30.1%,AA频率2.7%。研究结果证实鸡NRAMP1蛋白质223位突变改变其结构和理化性质，可能与该蛋白抗感染能力相关。     

家鸽IGF-Ⅱ的SNPs及与生长性状的相关性分析

采用PCR-SSCP和测序的方法检测家鸽类胰岛素样生长因子-Ⅱ基因片段的多态性,并将其单核甘酸多态性与生长性状进行了相关性分析。结果表明：在家鸽类胰岛素样生长因子-Ⅱ基因片段相对第98位发生G→C突变,该突变位点编码的氨基酸序列亦发生改变,由CGG突变为CCG,但仅存在两种基因型,即AA型和AB型,基因型频率分别0.6875和0.3125。     

家鸽IGF-Ⅱ的5NPs及与生长性状的相关性分析

采用PCR-SSCP和测序的方法检测家鸽类胰岛素样生长因子-Ⅱ基因片段的多态性,并将其单核甘酸多态性与生长性状进行了相关性分析.结果表明:在家鸽类胰岛素样生长因子-Ⅱ基因片段相对第98位发生G→C突变,该突变位点编码的氨基酸序列亦发生改变,由CGG突变为CCG,但仅存在两种基因型,即AA型和AB型,基因型频率分别0.6875和0.3125.     

家鸡Mx基因多态性及其诱变修饰的研究

研究采用错PCR-RFLP的方法对家鸡14个品种的Mx基因变异性分布进行了探索;并利用PCR突变技术将Mx基因全长cDNA第2032位碱基由G突变为A(即631位氨基酸的改变),并将突变的Mx基因插入真核表达载体pcDNA3.0,转染COS-I细胞,进行RT-PCR与间接免疫荧光(IFA)鉴定,研究结果显示,14个品种Mx基因的2032位点存在2个等位基因(A、G),3种基因型(AA、AG、GG),其中鹿苑鸡、狼山鸡、斗鸡未发现AA型个体,茶花鸡未发现GG个体;并成功对Mx基因进行PCR诱变修饰和构建了能够表达鸡Mx基因的重组真核表达载体,为其体内外表达及生物学活性的进一步研究奠定了基础.     

鸡腺苷琥珀酸裂解酶基因适用性进化分析

采用反转录-聚合酶链式反应（RT—PCR）方法，以肝脏总RNA为模板，对泰和乌骨鸡、隐性白羽肉鸡腺苷琥珀酸裂解酶基因（ADSL）编码区序列进行克隆和测序；并结合Gen—Bank中已提交的家鸡、鱼类、哺乳动物和人类等ADSL基因序列，采用基于最大似然法的密码子置换模型分析ADSL基因编码区序列在进化过程中承受的选择压力。结果RT—PCR方法准确获得了泰和乌骨鸡和隐性白羽肉鸡ADSL基因编码区序列，全长为1380bp。“分支特异模型”检验结果表明，ADSL基因在不同物种进化过程中较为保守，未受到正选择作用。鸡ADSL基因序列的“位点特异模型”检验未发现正选择位点。研究结果有助于了解鸡ADSL基因的结构及进化历程。     

鸡OBR基因第20外显子多态性与脂肪性状的相关研究

对鸡OBR基因的单链构象多态性进行检测，在第20外显子发现了1个新的单核苷酸多态位点。克隆测序了2种纯合子片段，在第20外显子编码区的860位碱基确认了1个由T变为C的突变，编码的氨基酸由缬氨酸突变为丙氨酸。在1个地方鸡杂交群体中检验这一多态位点与脂肪性状的相关，建立固定效应模型进行最小二乘分析，对脂肪性状的不同基因型效应进行差异显著性检验。结果表明：试验群体中AA、AB、BB基因型频率分别为0．641、0．292和0．067。     

闽西地区猪伪狂犬病毒变异株TK基因新变异序列鉴定

为了解闽西地区2013年以来猪伪狂犬病毒(PRV)流行株的现状、分子生物学特征和遗传演化规律,本试验收集了闽西不同地区的14株PRV分离株,并对其TK基因进行遗传变异分析。结果表明:14株PRV分离株的TK基因与其他参考毒株相应序列具有严格的保守性,这些毒株之间的核苷酸和氨基酸序列同源性分别为98.3%~99.8%和96.9%~99.4%。氨基酸多序列比对发现,14株PRV分离株在2个位点发生了独特性的氨基酸突变,即第16位氨基酸(除PRV FJLY04和FJLY06株外)由K突变为R和第129位氨基酸由S突变为G,这是国内首次报道TK基因在该位置发生氨基酸突变的毒株。其中,第16位氨基酸突变导致TK蛋白ATP结合结构域由-G**G*GK-转变为-G**G*GR-,同时该位点还位于TK蛋白的抗原表位区内。这些新的氨基酸突变与PRV致病性及其与生物学特性的关系有待进一步研究。     

不同鸡种TRNAL-AAG基因序列比较分析

本研究利用目标区域捕获测序技术对TRNAL-AAG(transfer RNA leucine(antico-don AAG))基因进行序列测定,找出不同鸡种TRNAL-AAG基因序列上的差异,为鸡抗病育种研究提供基础材料。利用MEGA X软件对25个鸡种和6种其他鸟类的基因序列进行比对分析,统计SNPs位点和Indel位点,并构建系统进化树进行分析。结果发现该基因SNP共19个,有义突变16个,均集中在序列第47位和第50位,可作为该基因有关抗病的候选SNPs位点。另外,该基因在25个鸡品种间高度保守,没有碱基插入或缺失且相似性高达98%,仅有雪山草鸡和北京油鸡存在一个有义突变,体现两品种在该基因上的多态性。进化树将31种鸟类分为两类:雪山草鸡和北京油鸡及所选6种鸟类聚为一类,其余鸡种聚为一类。说明鸟类品种间的同源性较小,不同鸟类品种TRNAL-AAG基因具有较为丰富的遗传多样性。     

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