青蒿素及其衍生物在动物生产中的应用研究

青蒿素是一种倍半萜内酯类化合物,其特殊的过氧基团结构使其具有抗疟疾、抗菌、抗炎、抗氧化、抗寄生虫、免疫调节、缓解热应激、促进生长等作用。青蒿素及其衍生物应用于动物生产中可以替代抗生素,具有广阔的应用前景。文章对青蒿素及其衍生物的生理功能、主要提取方式及在动物生产中的应用进行论述。     

青蒿素及其衍生物药理作用研究进展

青蒿素及其衍生物具有抗疟疾、抗肿瘤、抗血吸虫、抗弓形虫、抗纤维化、抗孕、抗心律失常等多种药理活性；但其作用机制、特点、应用研究仍处于初级阶段，因此具有广阔的研究开发前景。本文综述了国内外近年来对青蒿素及其衍生物药理作用及可能的相关机制的研究进展。     

青蒿素及其衍生物在肉鸡生产中的应用

青蒿素是从中药青蒿中提取的一种具有抗寄生虫、抗氧化、抗炎等生理功能的倍半萜内酯类化合物,系天然的饲料添加剂。在饲粮中添加青蒿素及其衍生物可抗鸡球虫、缓解热应激对肉仔鸡造成的损伤、改善生产性能等。文章阐述了青蒿素及其衍生物的生理功能和作用机制,在肉鸡生产中的应用,为更好地研究和应用青蒿素及其衍生物提供参考依据。     

青蒿素及其衍生物抗寄生虫的研究进展

本文介绍了青蒿素及其衍生物的基本研究状况和它们抗寄生虫病的研究进展，青蒿素及其衍生物主要的抗寄生虫作用表现为抗疟原虫和抗血吸虫，它们抗弓形虫、卡氏肺孢子虫、犬附红细胞体和球虫的作用也较强，对其进一步的研制和开发具有广阔的前号：     

青蒿素及其衍生物的药理研究与应用

70年代,我国医药工作者从菊科草本植物黄花蒿(Artemisia annua L.)和青蒿(A.apiaceaHance)中提取出一种抗疟有效成分青蒿素(Artemisinin),其后又研制出更有效的抗疟化合物蒿甲醚(Artemther)、青蒿琥酯(Artesunate)等一系列衍生物,为抗疟药研究开辟了新途径。近年来,青蒿素及其衍生物在兽医临床上的应用越来越广泛,在治疗牛、羊焦虫病,牛、兔血吸虫病和鸡球虫病等畜禽寄生虫病上展现出重要价值。本文就近10年国内对青蒿素及其衍生物在药理、毒理及临床应用方面的研究状况作一概述。     

青蒿素及其衍生物的作用机理及其对鸡球虫病的防治

对青蒿素及其衍生物的作用机理及近年来其在防治鸡球虫病的应用做了较详细的综述,以期为其在防治鸡球虫病中的应用提供参考。青蒿素被用于治疗疟疾已有几百年的历史,它还具有治疗血吸虫、腹泻及清热、镇静安神的作用,但其在兽医临床中的应用还是一个新领域。     

青蒿素及其衍生物抗寄生虫药理作用研究进展

青蒿素是从中药青蒿中提取出的有过氧基团的倍半萜内酯药物,其分子式是C15H22O5,抗疟的主要活性基团为过氧基团,易溶于丙酮、苯、氯仿、乙酸乙酯,可溶于乙醚、乙醇,不溶于水。青蒿素在体内的作用特点为分布广、吸收快、排泄快、代谢迅速。青蒿素类药物包含青蒿琥酯、蒿甲醚、双氢青蒿素、蒿乙醚。近年来有研究报道青蒿素及其衍生物对除疟原虫外其他寄生虫同样具较好的杀虫效果,例如日本血吸虫、弓形虫、肺孢子虫、球虫、锥虫等。论文就近些年来关于青蒿素类药物对寄生虫药理作用的研究进展做一综述。     

青蒿素在养殖中的应用及提取工艺研究进展

青蒿素具有抗疟、抗菌、解热和增强免疫等活性,对治疗某些动物疾病有显著效果。介绍青蒿素在养殖中应用的研究进展,分析提取青蒿素的前处理、萃取和提纯工艺的特点和效果,并浅析青蒿素在养殖中的应用前景。     

青蒿素的提取及蒿甲醚的合成

提取、分离青蒿素并合成其衍生物蒿甲醚。以溶剂法从青蒿中提取青蒿素,采用柱层析法进行纯化。通过还原、醚化反应制得其衍生物蒿甲醚。结果青蒿素收率好,纯度高;蒿甲醚合成收率达76．2％。该方法获得的产品质量稳定,产率高,成本低。     

抗血吸虫病药物的研究现状

血吸虫病是由分体科分体属的蠕虫引起的一种危害严重的寄生虫病,对吡喹酮、氯硝柳胺、青蒿素及其衍生物三类抗血吸虫病药物的作用机制、疗效、毒副作用进行了介绍。     

Salmonella in pork cuttings in supermarkets and butchers' shops in Denmark in 2002 and 2006

The prevalence of Salmonella in fresh pork cuttings in Denmark in the years 2002 and 2006 was investigated at retail and compared with the retail supply pattern. A total of 1025 and 3473 samples were taken in 2002 from butcher's shops and supermarkets, respectively. The corresponding numbers in 2006 were 259 from butchers' shops and 628 from supermarkets. In 2002, 1.2% of all samples were positive for Salmonella; butchers' shops and supermarkets had 1.8% and 1.0% positive samples, respectively. The overall prevalence in 2006 was 4.2%, with prevalence of 8.1% and 2.6% for butchers' shops and supermarkets, respectively. Hence, increases around 3- to 5-fold were found. There was neither observed any parallel increase in Salmonella positive carcasses in Danish slaughterhouses during the study period, nor were any changes in supply routes towards slaughterhouses with higher prevalence observed, which could explain the apparent increase. We hypothesize that hygiene levels and ability to avoid cross-contamination and prevent growth of the organism, in the meat processing chain after slaughter were the most likely responsible factors. Results from this study indicate that the hygiene performance, particularly at retail, has a significant impact on the occurrence of Salmonella. This implies that there is no direct link between slaughterhouse Salmonella surveillance data and the level of Salmonella contamination at retail. To improve risk assessment of Salmonella in fresh pork meat, this study underlines the need for comprehensive retail data.     

Sanguinarine metabolism and pharmacokinetics study in vitro and in vivo

Sanguinarine (SA) is a benzo[c] phenanthridine alkaloid which has a variety of pharmacological properties. However, very little was known about the pharmacokinetics of SA and its metabolite dihydrosanguinarine (DHSA) in pigs. The purpose of this work was to study the intestinal metabolism of SA in vitro and in vivo. Reductive metabolite DHSA was detected during incubation of SA with intestinal mucosa microsomes, cytosol, and gut flora. After oral (p.o.) administration of SA, the result showed SA might be reduced to DHSA in pig intestine. After i.m. administration, SA and DHSA rapidly increased to reach their peak concentrations (C_max, 30.16 ± 5.85, 5.61 ± 0.73 ng/ml, respectively) at 0.25 hr. Both compounds were completely eliminated from the plasma after 24 hr. After single oral administration, SA and DHSA rapidly increased to reach their C_max (3.41 ± 0.36, 2.41 ± 0.24 ng/ml, respectively) at 2.75 ± 0.27 hr. The half-life (T_1/2) values were 2.33 ± 0.11 hr and 2.20 ± 0.12 hr for SA and DHSA, respectively. After multiple oral administration, the average steady-state concentrations (C_ss) of SA and DHSA were 3.03 ± 0.39 and 1.42 ± 0.20 ng/ml. The accumulation indexes for SA and DHSA were 1.21 and 1.11. The work reported here provides important information on the metabolism sites and pharmacokinetic character of SA. It explains the reasons for low toxicity of SA, which is useful for the evaluation of its performance.     

Chlortetracycline in swine-bioavailability and pharmacokinetics in fasted and fed pigs

Chlortetracycline hydrochloride was administered intra-arterially (11 mg/kg) and as an oral drench (33 mg/kg) to ten 21.0-31.5-kg pigs. Five of the pigs were fasted 18 h prior to dosing and five of the pigs were fed ad libitum prior to dosing. The mean volume of distribution determined by area-under-the-curve calculations for the fasted pigs (0.967 +/- 0.210 l/kg) was significantly less (P less than 0.05) than the mean volume of distribution for the fed pigs (1.39 +/- 0.31 l/kg). Mean total body clearance of the drug was also significantly less (P less than 0.05) in the fasted pigs (0.165 +/- 0.055 l/kg/h) as compared to the fed pigs (0.307 +/- 0.053 l/kg/h). The elimination constants (beta) were not found to be statistically different (P less than 0.05): 0.1811 +/- 0.0057 for the fasted pigs; 0.2260 +/- 0.0461 for the fed pigs. The bioavailability for both groups was similar; 19.12 +/- 8.3% for the fasted pigs and 17.88 +/- 5.3% for the fed pigs. In a second experiment three groups of six pigs which weighed 34.5-44.1 kg were fed a corn-soy diet ad libitum. The rations were fortified with chlortetracycline at 100, 400 or 1000 mg chlortetracycline hydrochloride/kg feed. Chlortetracycline concentrations were determined in plasma samples collected over a 6-day period. Plasma chlortetracycline concentrations reach a plateau within 24 h after initial access to the trial diets and were highly correlated with the dose of the drug consumed (r2 = 0.97).     

Helminth and protozoan parasites in dogs and cats in Belgium

This study investigates the level of helminthic and protozoal infestation over the last 10 years in strays, well-cared-for dogs and cats. Determination of the prevalence of infections was based either on faecal examination or on worm counts at necropsy. Of 2324 faecal flotations (NaCl sp.gr. 1.20) of stray dogs, 34.2% had eggs or proglottids of one or more worm species consisting of Toxocara canis (17.4%), Toxascaris leonina (10.1%), Uncinaria stenocephala (11.4%), Trichuris vulpis (7.0%) and cestodes (2.1%). Isospora oocysts were observed in 5.2% of the dogs. The data on the distribution of the various worm species in the positive dogs indicate that T. canis eggs were by far the most common (50.9%). Necropsy data from 212 infected dogs indicate that 38.9% were infected with T. canis and 33.7% with T. leonina. The overall prevalence of worm infestation of 246 well-cared-for kennel dogs, based on worm egg counts by the McMaster technique, was 36.1%. Of 30 feline faecal samples examined by flotation, 83.3% were positive for parasites, including Toxocara cati (60%), Ancylostoma tubaeformae (36.6%), Taenia (Hydatigera) taeniaeformis (20%) and coccidia (30%). Toxocara cati was the most frequently found worm species at the necropsy of 25 cats (52%). Toxoplasma was not observed.     

2005年国内蛋、肉鸡市场分析回顾及2006年走势预测

2005年如果没有年底的禽流感疫情,对于我国蛋鸡、肉鸡生产来说应该是一个非常完美的丰收年,是哪些因素导致了2005年蛋鸡市场如此好的行情?2006年我国家禽市场又将走向何方?……作者对以上热点问题进行了深入分析研究,供读者参考。     

Pharmacokinetics of penicillin-G in ewes and cows in late pregnancy and in early lactation

Concentrations of penicillin-G in serum were determined after single intravenous doses of potassium penicillin-G (10 mg/kg body wt) to ewes and cows in late pregnancy and in early lactation. Penicillin-G in serum was analysed by a microbiological method and pharmacokinetic parameters were calculated by model-independent methods. Serum concentrations were lower in early lactation than in late pregnancy in both ewes and cows. The differences were statistically significant at most sampling times in ewes but only during the first hour in cows.
Weight corrected values of clearance and volume of distribution were significantly higher in early lactation than in late pregnancy in both ewes and cows. Mean residence time and elimination-half life were shorter in lactating than in pregnant ewes, however for the latter parameter the difference was not statistically significant. Neither of these parameters changed in cows.
It is concluded that in both ewes and cows pharmacokinetic parameters of penicillin-G are altered from late pregnancy to early lactation but that these changes have little practical impact and do not call for a revised dosage regime of the studied drug.