一种测定饲料中氯羟吡啶残留的快速电化学检测方法

为探索检测氯羟吡啶等广谱抗球虫药物快速、灵敏的检测方法,本文采用玻碳电极为工作电极,建立了伏安法检测氯羟吡啶的电化学行为。结果表明:氯羟吡啶在1.45 V处具有氧化峰电流,检测的线性范围为1.7×10-7mol/L至2.3×10-5mol/L,检测限为1.4×10-8mol/L,回收率达93.7%。当玻碳电极用Nafion-二茂铁修饰后,可显著提高检测的特异性及灵敏度,使检测下限达1.8×10-9mol/L。同时本文就不同支持电解质溶液、pH值、断路富积时间对测定结果的影响及修饰电极的再生等进行了详细的探讨。     

Nafion修饰电极检测饲料中克伦特罗的研究

为探索检测克伦特罗等激素类药物快速、灵敏的检测方法,本文采用玻碳电极为工作电极,以伏安法检测了克伦特罗的电化学行为。克伦特罗在+1.24V处具有氧化峰电流,检测的线性范围为1×10-7mol/l～1×10-5mol/l,检测限为1×10-8mol/l,回收率达97%。当玻碳电极用Nafion修饰后,可显著提高检测的特异性及灵敏度,使检测下限达1×10-9mol/l。同时本文对不同支持电解质溶液、pH值、断路富积时间对测定结果的影响及修饰电极的再生等进行了详细的探讨。     

离子液体-石墨烯修饰碳纤维微电极电化学性能研究

本实验制备了离子液体-石墨烯修饰碳纤维微电极,采用循环伏安法和差分脉冲伏安法测定多巴胺(DA)在该修饰电极上的电化学行为。实验结果显示,修饰后电极的稳定性和重现性明显增加,DA在修饰电极上的氧化过程受扩散控制。在5×10-7-1×10-4mol/L浓度范围内,DA在修饰电极上的氧化峰电流与其浓度呈现良好的线性关系。     

涂丝型离子选择电极检测猪饲料中的恩诺沙星

建立电位分析法对饲料中的恩诺沙星进行检测。以恩诺沙星与六碘合铋形成的缔合物为电活性物,制备具有Nernst响应的涂丝型恩诺沙星选择电极,并对其各项性能进行测定。测定结果表明,电极线性响应范围为0.1~1.0×10~(-5)mol/L,级差电位为26 mV/p C,检测下限为8.9×10~(-6)mol/L。将电极应用于猪饲料样品中恩诺沙星含量的检测,并与超高效液相色谱法(UPLC)对比,结果相符。     

不同浓度氟对山羊成骨细胞周期和凋亡的影响

为了探讨氟化物对反刍动物成骨细胞的细胞周期和凋亡的影响,本研究以初生山羊股骨骨膜为材料分离成骨细胞,接种于含15?S的DMEM培养液,于37℃、5%CO2的培养箱中培养。通过形态观察(Hoechst33342/PI双重染色)、DNA ladder电泳、透射电镜、流式细胞仪等方法检测氟对成骨细胞的调控作用。结果表明,高氟(1.0×10-3及2.5×10-3mol/L)使成骨细胞G0/G1期减少,S期细胞增多,抑制成骨细胞周期由合成DNA的S期向G2M期转化,使细胞停滞在S期。1.0×10-5~2.5×10-3mol/L氟可使DNA断裂,诱导成骨细胞凋亡,其中1.0×10-4mol/L氟所致早期和晚期凋亡率最高,分别为3.33%和2.92%。本试验证实氟可诱导成骨细胞凋亡。     

基于碳纳米管/分子印迹聚合物修饰电极对双酚A的测定研究

在碳纳米管修饰的玻碳电极表面滴涂双酚A分子印迹聚合物,制备了分子印迹聚合物/碳纳米管修饰电极。优化了碳纳米管浓度、分子印迹聚合物浓度、富集时间、pH等对传感器的测定条件,结果表明,当碳纳米管浓度为0.3 mg/mL,分子印迹聚合物浓度为0.5 mg/mL,富集时间为5 min,pH为8.0,分子印迹修饰电极对双酚A具有最大的电化学响应。在最优的实验条件下,采用差分脉冲伏安法对双酚A进行测定,峰电流与双酚A浓度在0.1~100.0μM范围内呈现良好的线性关系,检测限为0.5μM(S/N=3)。该分子印迹修饰电极的电化学传感器成功应用于嘉兴南湖水、自来水、纯净水中双酚A的含量测定。     

SP刺激对内蒙古绒山羊皮肤干细胞的影响

本研究旨在探讨不同浓度P物质(SP)对内蒙古绒山羊皮肤干细胞分化及生长状况的影响。通过设立0mol/L(对照组)、1×10-5mol/L、1×10-6mol/L、1×10-7mol/L、1×10-8mol/L、1×10-9mol/L 6个浓度梯度的SP对内蒙古绒山羊皮肤干细胞进行刺激。结果表明:0 mol/L组(对照组)出现细胞团、细胞生长较均一,多呈铺路石状紧密排布,SP刺激组未见成团细胞出现、开始出现长梭形细胞、细胞生长不再均一,不同类型的细胞组织在一起,并有明显的细胞分界出现;与低浓度SP刺激组相比高浓度SP刺激组绒山羊皮肤干细胞相对散乱,整体性差;生长曲线显示,与对照组相比,各组细胞对数期均为4 d左右,只是调整期略有不同,1×10-6mol/L对增值影响相对明显。揭示了SP刺激对内蒙古绒山羊皮肤干细胞分化、增殖生长有一定的促进作用。     

硒镉互作对体外培养鸡淋巴细胞硒蛋白K和硒蛋白S表达的影响

为了探讨镉对体外培养鸡淋巴细胞硒蛋白S和硒蛋白K表达的影响及硒的颉颃作用,试验在体外培养鸡脾脏淋巴细胞的培养液中分别添加硒1×10-7mol/L、镉1×10-6mol/L和硒1×10-7mol/L加镉1×10-6mol/L,分别在培养的12,24,36,48小时采用实时PCR法检测硒蛋白K和硒蛋白S mRNA表达量。结果表明:硒能够显著提高镉诱导的硒蛋白K和硒蛋白S mRNA的表达量,镉能够降低体外培养鸡淋巴细胞硒蛋白K和硒蛋白S的表达量。     

美洛托宁对猪卵母细胞体外成熟的影响及受体介导机制探究

为了探究美洛托宁对猪卵母细胞体外成熟的影响及其受体介导机制,试验采集健康母猪卵巢中的卵母细胞,采用免疫荧光检测猪卵母细胞MT受体表达情况;在体外成熟培养液中分别加入不同浓度的美洛托宁(0,1×10~(-5),1×10~(-6),1×10~(-7) mol/L),筛选对猪卵母细胞成熟和胚胎发育的最适浓度;根据最佳美洛托宁添加浓度,成熟液中分别添加1×10~(-6) mol/L的美洛托宁、MT受体激动剂、 MT受体颉颃剂和1×10~(-6) mol/L MT受体颉颃剂+1×10~(-6) mol/L美洛托宁,检测美洛托宁及其受体激动剂和颉颃剂对猪卵母细胞成熟和胚胎发育的影响;收集添加1×10~(-6) mol/L的美洛托宁24 h处理组、空白对照组、MT受体颉颃剂处理组、美洛托宁和MT受体颉颃剂组母猪卵母细胞复合物,利用试剂盒检测卵母细胞cAMP和cGMP含量。结果表明:当美洛托宁浓度为1×10~(-6)mol/L时,猪卵母细胞的分裂率和囊胚率均达到最高,分别为76.26%和31.48%,与空白对照组相比差异显著(P0.05);在成熟液中添加1×10~(-6)mol/L美洛托宁和1×10~(-6)mol/L MT受体激动剂,两组细胞极体排出率均较高,与空白对照组相比差异显著(P0.05),1×10~(-6)mol/L MT受体激动剂和1×10~(-6)mol/L美洛托宁的分裂率分别为75.16%和75.33%,囊胚率分别为30.04%和30.36%,与空白对照组相比差异显著(P0.05);在成熟液中添加1×10~(-6)mol/L的美洛托宁可以显著降低cAMP的含量和显著升高cGMP的含量(P0.05)。说明美洛托宁通过与细胞膜G蛋白偶联受体结合,从而抑制了cAMP合成,提高cGMP含量,进而促进猪卵母细胞成熟及早期胚胎发育。     

国产妥曲珠利对柔嫩艾美耳球虫临床疗效试验

目的评价国产妥曲珠利对柔嫩艾美耳球虫的治疗效果,确定最佳用药剂量。方法以50×10-6mg/L、25×10-6mg/L、12.5×10-6mg/L和6.25×10-6mg/L4个剂量,饮水给药2 d进行了妥曲珠利对E.tenella的临床疗效试验。结果50×10-6mg/L和25×10-6mg/L剂量的ACI分别为190.22和187.72,12.5×10-6mg/L ACI为152.86,6.25×10-6mg/L剂量的ACI为118.50。结论妥曲珠利以25×10-6mg/L剂量饮水治疗E.tenella效果好,可以推广使用。     

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