转移抗猪瘟病毒核酶基因兔的研究

采用显微注射法，将构建的绵羊金属疏因（ｏＭＴ）基因启动子与抗猪瘟病毒核酶（ＨＣＶ－Ｒｉｂｏｚｙｍｅ．ＨＲ）基因融合的质粒ｐＭＨＲ＿（３２）线性ＤＮＡ分子约２００～４００个基因拷贝导入兔原核胚的雄原核中，１５９枚导入基因胚移植给９只受体兔，产仔２２只，移植成活率为１３．８％。２２只仔兔经聚合酶链式反应（ＰＣＲ）和核酸探针杂交检测，６只体内整合有外源目的基因，整合率为２７．３％。再用１００个半数反应量（ＲＩＤ＿（５０））的猪瘟病毒Ｃ系兔化弱毒兔体攻毒，４只外源基因整合的实验兔能完全或部分抵抗ＨＣＶ弱毒攻击，不产生或无明显发热反应；而对照兔和６只ＨＲ基因未整合的实验兔不能抵抗ＨＣＶ弱毒攻击，出现特征性的稽留热型。逆转录聚合酶链式反应（ＲＴ－ＰＣＲ）和ＲＮＡ探针杂交检测４只转基因兔，两只肝中表达出ｏＭＴ－ＨＲｍＲＮＡ。认为微注射导入的外源ＨＲ基因在兔体内得到了整合和表达     

核基质附着区(MAR)调控的人胰岛素样生长因子(hIGF-1)转基因兔的制备

用ＥｃｏＲＩ＋ＨｉｎｄⅢ双酶解含鸡α－珠蛋白基因５′端核基质附着区（ＭＡＲ）、小鼠金属硫蛋白基因启动子（ＭＴ－１）和人胰岛素样生长因子－１（ｈＩＧＦ－１）基因的ｐＭＴＳＭＣＡＧ质粒，０．６％琼脂糖凝胶电泳，玻璃乳回收纯化ＭＡＲ／ＭＴ／ｈＩＧＦ－１片段（３．９ｋｂ），用该片段制备转基因兔。利用水平显微注射系统注射１－细胞兔胚胎４６８枚，移植到３６只受体兔，有８只妊娠，共产下１９只活仔兔。采仔兔耳样提取基因组ＤＮＡ，应用ＰＣＲ技术分析其外源基因整合情况，获得８只阳性兔（显示出约６００ｂｐ外源ＤＮＡ条带）。再对８只阳性兔的ＰＣＲ产物进行Ｓｏｕｔｈｅｒｎ印迹杂交，得到５只整合有ＭＡＲ／ＭＴ／ｈＩＧＦ－１外源基因的转基因兔，转基因整合率为２６．３％（５／１９）。用１只阳性转基因公兔（５０２号）繁殖了６窝，共获得４２只仔兔。采仔兔耳样提取基因组ＤＮＡ后，如上用ＰＣＲ分析和做Ｓｏｕｔｈｅｒｎ印迹杂交，Ｆ１代中有５只整合有ＭＡＲ／ＭＴ／ｈＩＧＦ－１融合基因。     

猪胚胎移植技术研究

利用外源激素PMSG+HCG处理母猪58头,同期发情有效率和超排成功率分别为89.3％(25/28)和100％(30/30)。14头供体用手采集胚胎,平均每头排卵23.6±6.2个,共获得胚胎218枚,其中可利用胚胎206枚,胚胎可利用率为94.5％。将143枚胚胎移植给10头 受体,平均每头移植14.3±3.6枚,8头受体妊娠并产仔52头,移植妊娠率为80％(8/10),平均每头产仔6.5头,妊娠母猪胚胎存活产仔率为45.6％(总产仔数/胚胎移植总数)。仔猪初生平均体重为1.25±0.28公斤。其中12头供体手术冲卵后,第1个情期发情配种受胎率为91.8％(11/12)。     

猪的胚胎移植

177枚受精卵或2—细胞期胚胎,手术法移植到8头发情同期化的青年母猪体内,结果有4头妊娠,其中3头受体足月产仔22只,另一头受体在妊娠88天后宰杀,有6个发育正常的胎儿。移植受体妊娠率50％(4/8),移植卵成仔(胎)率15.8％(28/177)。     

兔核移植胚胎的克隆研究

本研究改进了兔受体卵母细胞的去核程序及供体卵裂球的处理方法，并对核移植胚的体外克隆、继代克隆及克隆胚的体内发育进行了试验。结果表明：卵龄对受体卵母细胞的去核具有显著的影响，卵龄为１５～１８ｈ的去核率为１００％（４５／４５），显著高于１３～１４ｈ的４６．６％（７／１５），Ｐ＜０．０１。ＤＮＡ合成抑制剂Ａｐｈｉｄｉｃｏｌｉｎ处理１６－细胞期卵裂球后，重组胚的囊胚发育率５４％（２０／３７）高于未处理组的４５％（１４／３１），Ｐ＜０．０５。从２枚１６－细胞供体胚分别获得来自一个供体胚的９枚和７枚核移植克隆囊胚，囊胚发育率为５１．６（１６／３１）。然而第一次继代核移植胚的囊胚发育率仅为１１．５％（６／５２）。１６－及３２－细胞期卵裂球的重组胚可发育至产仔，共获２窝８只仔兔。其中１只、２只、２只和３只仔兔分别来自４个供体胚。     

移植奶牛胚胎冷冻后分割成的二分胚生产同卵双生犊牛的实验

对解冻后品质优良的Ａ级囊胚进行分割，并将二分胚移植生产同卵双生犊牛。结果表明：９枚Ａ级囊胚切割成１８枚半胚，胚胎分割成功率１００％。单胚移植受体６头。妊娠２头，妊娠率３３．３％；双半胚移植６头，妊娠２头，妊娠率３３．３％。     

水平显微注射法制备转基因小鼠的研究

由于传统显微注射法具有操作繁琐、技术要求高和外源基因导入率低等局限性,本试验对常规显微注射法进行改进,旨在建立一套比较完善的水平显微注射方法。采用水平微注射系统,将外源DNA片段导入胚胎的雄原核中,获得子代鼠,分娩后3周提取鼠尾基因组DNA,PCR法筛选转基因阳性鼠。本试验采用Puc/BLG IN S和Chym os in基因,共使用710枚鼠原核胚进行研究,胚胎经注射后移植了25只受体,产下仔鼠77只;妊娠率分别为33.3%(5/15)和50%(5/10),胚胎成活率分别为9.47%(41/433)和l3.00%(36/277),阳性率分别为4.88%(2/41)和8.33%(3/36)。将阳性雌鼠配种妊娠后,对外源基因整合情况进行检测,结果表明初步获得了转基因阳性小鼠。     

显微注射生产转人胰岛素原基因奶山羊

将构建的绵羊β－乳球蛋白基因（BLG）调控人胰岛素原基因的重组基因通过显微注射生产转基因奶山羊。同期化超排处理供体奶山羊15只，排卵262枚，回收卵221枚，移植206枚注射卵，移植受体68只，怀孕21只（妊娠率33％，其中成年母羊妊娠率为58．62％，周岁母羊为9．4％），产羔33只，其中母羊羔8只，公羔25只。经PCR检测及酶切分析，证明有5只为阳性，阳性整合率15．15％，但5只全为雄性。     

自体移植情况下移入胚数对猪基因导入效率的影响

为了探讨在自体移植的情况下,每头受体移入的微注射基因胚胎的数量对猪基因导入总效率的影响,在导入ＰＥＦｈＤＡＦ（Ｈｕｍａｎｄｅｃａｙａｃｃｅｌｅｒａｔｉｎｇｆａｃｔｏｒ,人类补体衰减加速因子）基因的实验过程中,将受体母猪按称入胚数分成三组：第一组１２～１５枚,第二组１６～２０枚,第三组２１～３２枚,其受孕率分别为８０％,９０．９％,和７０％,三组之间的差异不显著（Ｐ〉０．０５）;共产仔率分别为１９．     

外源基因导入猪受精卵的研究

本文报道了利用显微注射法把外源抗口蹄疫基因导入猪受精卵进行基因转移研究的初步结果,本试验采用PMSG和HCG超排初情期前青年母猪45头,发情39头,经检查共有856个排卵点,平均每头排卵21.95个;从输卵管内冲出746枚早期胚胎,选用530枚1—细胞或2—细胞胚胎进行离心,选其503枚胚胎进行显微注射抗品蹄疫基因,并分别移植给20头受体猪,结果有16头不返情(80%,16/20),6头流产,10头妊娠产仔,共产仔61头,活仔34头,死胎17头,木乃伊10头。     

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 -