妥曲珠利对肉鸡生长性能和免疫机能的影响

本试验旨在研究饮水中添加不同水平妥曲珠利对肉鸡生长性能和免疫机能的影响.288只1日龄AA肉仔鸡,随机分为4组.各组日粮相同,对照组(1组)饮用自来水,试验组(2组、3组和4组)于8～10日龄连续3d饮水中分别添加妥曲珠利25mg/L、50 mg/L和100 mg/L,试验期42 d.结果表明,妥曲珠利对肉鸡生长性能和血清新城疫抗体效价均无显著影响(P＞0.05);25mg/L和50 mg/L妥曲珠利组肉鸡28日龄胸腺指数和脾脏指数显著高于对照组(P＜0.05),100mg/L妥曲珠利组肉鸡28日龄腔上囊指数显著低于对照组(P＜0.05);50 mg/L妥曲珠利组外周血T淋巴细胞的转化率显著高于对照组(P＜0.05).可见,饮水中添加25 mg/L和50 mg/L妥曲珠利对肉鸡免疫机能有一定促进作用.     

常山口服液抗鸡柔嫩艾美耳球虫广东分离株的疗效研究

研究旨在明确常山口服液治疗鸡球虫病的疗效和最佳给药剂量。试验选取90只14日龄健康雏鸡,随机分为9组,每组10只,即常山口服液组(分别为2.5、5.0、15.0、25.0、35.0、50.0 m L/L水剂量)、妥曲珠利组(1 m L/L水)、感染对照组和健康对照组。除健康对照组外,每只鸡接种7×104个柔嫩艾美耳球虫广东分离株的孢子化卵囊,饮水给药7 d,观察其疗效。结果显示,常山口服液各剂量组其盲肠和十二指肠的肿胀现象较感染对照组明显减轻,血液性内容物明显减少,抗球虫指数(ACI)分别为87.7、136.2、141.8、136.2、109.7和108.0,均高于感染对照组;常山口服液按5.0、15.0及25.0 m L/L水剂量给药,抗球虫指数均高于对照药物妥曲珠利组(ACI=124.8)。结果表明,人工感染条件下,常山口服液较化学药物妥曲珠利具有更好的抗球虫疗效,且作为中药提取物,疗效对比试验效果较为理想。     

妥曲珠利治疗鸡球虫病用药方案的优化

目前,妥曲珠利的用药时间和用药途径及其治疗效果存在争议。为了确定妥曲珠利对鸡球虫病的最佳用药时间和途径,本试验以自由饮水和灌服两种途径分别在感染球虫孢子化卵囊后24、48、72 h连续用药2 d,通过抗球虫指数（anticoccidialindex,ACI）、排卵囊减少率和死亡率等指标分析妥曲珠利饮水剂合理用药方案。结果表明,感染后24 h用药妥曲珠利可有效控制鸡柔嫩艾美耳球虫病,48 h后治疗效果不佳;嗉囊灌服的治疗效果优于自由饮水。本试验结果为生产中有效利用妥曲珠利控制鸡球虫病提供了重要依据。     

妥曲珠利对肉鸡血清生化指标的影响及停药后肝脏沉积的消减研究

(目的)本试验旨在研究饮水中添加不同水平妥曲珠利对肉鸡血清生化指标的影响及停药后在肝脏沉积量的消减特点。(方法)选用288只1日龄AA肉鸡,随机分4组,每组6个重复。对照组(1组)饮用常规自来水,2组、3组和4组于8~10日龄饮水中分别添加妥曲珠利25、50、100mg/L,其它时间饮用常规自来水,试验期42d。(结果)结果表明,25mg/L妥曲珠利对肉鸡血清淀粉酶活性无显著影响(P0.05),可显著提高血清总蛋白和葡萄糖含量(P0.05);50mg/L和100mg/L妥曲珠利使血清淀粉酶活性和总蛋白含量显著降低(P0.05);25mg/L、50mg/L和100mg/L妥曲珠利使血清总超氧化物歧化酶活性显著或极显著下降(P0.05或P0.01)。肝脏中妥曲珠利沉积量具有显著剂量效应。停药7d,各试验组均已检测不出妥曲珠利。药物沉积量下降趋势符合指数函数模型,经预测模型计算得出,2组、3组、4组分别于停药后5.02、6.10、6.59d肝脏中沉积的妥曲珠利基本消失。(结论)综上所述,妥曲珠利对肉鸡血清生化指标的影响及其在肝脏中的沉积量均具有明显剂量效应,停药后肝脏药物的衰减速度较快。     

妥曲珠利在鸡组织内的残留研究

研究鸡单剂量喂服(50 mg/kg·d,100mg/kg·d,连服2 d)妥曲珠利后在肝脏、肾脏、肌肉组织中的残留量,以便制定妥曲珠利预混剂的休药期.用乙腈-乙酸乙酯(3/2,v/v)提取组织中的药物,利用高效液相色谱法测定组织中妥曲珠利的浓度.试验结果表明,100mg/kg饲料添加妥曲珠利在鸡体内休药期为14 d,50 mg/kg时休药期为8 d.该结果与农业部制定的无公害食品饲养兽药使用准则中所规定的75～100 mg/kg鸡饮水妥曲珠利的休药期一致.     

妥曲珠利微晶体的制备及其在家兔体内的药动学

采用反溶剂法制备妥曲珠利微晶体,利用显微镜观察妥曲珠利微晶体与妥曲珠利原药显微特征差异,并在25℃条件下测定两者体外溶出速率差异。将12只家兔随机分为2组,每组6只,分别按药物剂量10mg/kg灌胃,单剂量给药,采用HPLC检测血药浓度;用DAS2.0药代动力学程序计算药代动力学参数。结果显示,成功制备了妥曲珠利微晶体,微晶体与原药的显微特征差异明显,体外溶出速率明显加快;家兔单剂量灌胃妥曲珠利和微晶体后,主要药动学参数Cmax分别为（8.925±0.360）mg/L和（12.510±0.525）mg/L,tmax均为24h,AUC（0-∞）分别为（411.605±20.918）mg/（L·h）和（578.650±11.664）mg/（L·h）,相对生物利用度为140.6%,药时数据符合一级吸收二室模型。结果表明,HPLC法适用于妥曲珠利血浆浓度的测定;妥曲珠利微晶体与妥曲珠利原药相比,体内吸收速率和吸收程度有较大的提高。     

妥曲珠利对肉鸡屠宰性能的影响及在肌肉中残留的研究

本试验旨在研究妥曲珠利对肉鸡屠宰性能的影响及其在肌肉中的残留。选取288只初生AA肉鸡,随机分4组,每组6个重复,饲喂相同基础日粮,对照组(1组)饮用常规自来水,试验组(2、3、4组)8¹0日龄饮水中分别添加25、50、100 mg/L妥曲珠利,试验期42 d。结果表明:妥曲珠利对肉鸡屠宰性能无显著影响(P>0.05),在肌肉中沉积的剂量效应显著(P<0.05);药物沉积量下降趋势符合指数函数模型,根据模型预测,2、3、4组胸肌中妥曲珠利分别于停药后3.42、4.74、5.73 d衰减到HPLC法最低检测限(74.45 ng/g)。综上所述,饮水中添加低于100 mg/L的妥曲珠利对肉鸡屠宰性能无影响,该药在肌肉中沉积的剂量效应显著。     

国产妥曲珠利对小鼠的急性毒性和亚慢性毒性试验

为了探讨妥曲珠利对小鼠的毒性作用,评价其临床用药的安全性,进行了妥曲珠利对小鼠的急性毒性和亚慢性毒性试验.结果表明,妥曲珠利对小鼠无毒性作用,经口LD50为5 011 mg/kg.妥曲珠利以500、100、20 mg/kg给小鼠连续灌胃30 d,500mg/kg表现出生长缓慢、肝脏损伤,100mg/kg和20 mg/kg剂量组鼠的体重、脏器系数、血液指标均与空白对照组无差异(P＞0.05).表明妥曲珠利毒性小,临床推荐剂量是安全的.     

二硫代碳酸香芹酚酯对人工诱发鸡球虫病的疗效实验

为了评价二硫代碳酸香芹酚酯的抗球虫效果,将其按100、150、200mg/kg浓度添加于饲料中治疗人工感染鸡柔嫩艾美耳球虫病,设妥曲珠利25mg/kg、地克珠利2mg/kg浓度拌料给药作对照。结果显示,二硫代碳酸香芹酚酯高、中两种剂量治疗鸡球虫病具有良好的效果,抗球虫指数均在160以上,与妥曲珠利的效果相当,属于中效抗球虫药。临床推荐150mg/kg拌料给药,连用7d。     

纳川珠利溶液剂对鸡球虫病的药效学研究

对两种不同配方的0.3%纳川珠利溶液剂,分别以6、3、1mg/L三种剂量饮水预防人工感染的鸡柔嫩艾美耳球虫,并用地克珠利预混剂以1mg/kg剂量作为对照。结果显示,0.3%纳川珠利溶液剂的两种配方以上述3种剂量饮水预防鸡球虫病,具有良好的抗球虫效果,抗球虫指数在180以上,属高效范围。表明0.3%纳川珠利溶液剂是纳川珠利的一种高效预防鸡球虫病的良好剂型。     

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