马杜霉素对肉仔鸡红细胞免疫功能的影响

200只1日龄铁脚麻肉仔鸡,随机分为4组,每组5个重复。11日龄起在玉米-豆粕型基础日粮中分别添加0,5.0,7.5,10.0 mg/kg的马杜霉素,连续饲喂4周,试验期为7周。每7 d测定各组雏鸡红细胞补体受体花环率(C3bRR)及免疫复合花环率(ICR),观察不同剂量马杜霉素对肉仔鸡红细胞免疫功能的影响效应及其规律。试验结果表明:5.0 mg/kg饲料的马杜霉素连续饲喂4周对肉仔鸡红细胞免疫功能无明显影响(P>0.05)。7.5 mg/kg和10.0 mg/kg饲料的马杜霉素可降低C3bRR和升高ICR,C3bRR分别在用药后第21天和第14天起至第28天明显低于对照组(P<0.05或0.01),ICR在用药后第21天起至停药后第7天明显高于对照组(P<0.05或0.01)。由此表明,7.5 mg/kg饲料以上的马杜霉素对铁脚麻肉仔鸡红细胞免疫功能具有抑制作用,并随用药剂量升高和用药时间延长而加重;其抑制作用能持续至停药后第7天,但能在停药后21 d内逐步恢复正常。     

马杜霉素对肉仔鸡的毒性研究进展

马杜霉素具有作用强、用药浓度低、抗球虫谱广和不易产生耐药性等优点而广泛用于肉鸡抗球虫。但其毒性大、安全范围窄,易导致肉仔鸡中毒,从而抑制仔鸡生长发育、损伤实质器官、影响机体代谢和免疫功能。肉仔鸡品种、受试日龄及给药方式不同,其马杜霉素中毒剂量以及中毒后生长发育、临床病理学指标、机体免疫功能、组织器官重要活性物质等指标受影响的程度也有较大差异。马杜霉素拌料饲喂剂量不应超过6.5 mg/kg,以5.0 mg/kg饲喂时间不应超过2周;而饮水给药剂量应小于或等于2.5 mg/kg。     

马杜霉素对肉仔鸡免疫器官发育影响的研究

为了探讨马杜霉素对肉仔鸡免疫器官的影响,试验选择体重相近的1日龄肉仔鸡200只,在日粮中分别不添加马杜霉素(Ⅰ组)和添加5.0 mg/kg(Ⅱ组)、7.5 mg/kg(Ⅲ组)、10.0 mg/kg(Ⅳ组)的马杜霉素,连续饲喂4周,测定各组雏鸡胸腺、脾脏、法氏囊指数。结果表明:5.0 mg/kg马杜霉素3周对肉仔鸡免疫器官发育有一定促进作用,但3周后呈现一定的抑制作用;用7.5 mg/kg和10.0 mg/kg马杜霉素饲喂1周即可抑制免疫器官的生长发育,其抑制作用能持续至停药后1周,但在停药3周后基本恢复正常。说明马杜霉素对肉仔鸡免疫器官发育的抑制作用呈现一定的量效和时效效应。     

不同药物对猪气喘病抗体水平影响的研究

为研究不同剂量的泰妙菌素和强力霉素对猪气喘病的治疗水平,通过饲喂不同剂量的泰妙茵素和强力霉素,4星期后抽血检测抗体水平。结果,空白对照组阳性率为60％,给药50毫克／千克泰妙茵素与强力霉素的低剂量组阳性率均为20％,100毫克／千克泰妙菌素与强力霉素的高剂量组阳性率均为10％;阳性减少率,泰妙菌素低剂量组为64％、强力霉素低剂量组为59％、泰妙菌素高剂量组为82％和强力霉素高剂量组为75％。高剂量的泰妙菌素和强力霉素效果要好于低剂量组,泰妙菌素效果略好于低剂量组。结果表明,泰妙菌素和强力霉素对自然发病的猪气喘病有明显控制作用。     

马杜霉素对肉仔鸡淋巴细胞免疫功能和新城疫免疫效果的影响

200只1日龄铁脚麻肉仔鸡,随机分为4组,每组50个重复。从11日龄起在玉米-豆粕型基础日粮中分别添加0 mg/kg(Ⅰ组)、5.0 mg/kg(Ⅱ组)、7.5 mg/kg(Ⅲ组)、10.0 mg/kg(Ⅳ组)的马杜霉素,连续饲喂4周,实验周期为7周。观察不同剂量马杜霉素对肉仔鸡外周血T淋巴细胞转化能力、脾脏淋巴细胞周期、新城疫抗体效价的影响效应及其规律。结果表明,7.5 mg/kg饲料以上的马杜霉素连用4周对铁脚麻肉仔鸡淋巴细胞免疫功能和新城疫抗体效价具有抑制作用,并随用药剂量升高和用药时间延长而加重;其抑制作用能持续至停药第7天后逐步恢复正常。     

复鸡方毒盐支酸原土体霉和素大、泰肠妙杆菌菌素混可合溶感性染粉的对疗效试验

通过人工诱病鸡毒支原体和大肠杆菌混合感染,用复方盐酸土霉素、泰妙菌素可溶性粉进行治疗试验,结果表明:高剂量组(含盐酸土霉素360mg/L、泰妙菌素120mg/L)、中剂量组(含盐酸土霉素180mg/L、泰妙菌素60mg/L)的治疗有效率分别为90.0%、83.3%,均高于单个的盐酸土霉素组(含盐酸土霉素180mg/L)60.0%(P<0.05)与单个的延胡索酸泰妙菌素组(含延胡索酸泰妙菌素60mg/L)63.3%(P>0.05)。本研究显示,盐酸土霉素与延胡索酸泰妙菌素联合使用,能够增强治疗效果。     

马杜霉素在鸡组织中残留消除及临床毒性的研究

本文报道以3.0、5.0、7.0和9.0mg/kg马杜霉素剂量水平添加到饲料中饲喂AA肉鸡,研究马杜霉素对肉鸡的毒性作用及其在鸡组织中的残留消除。从临床症状、增重与饲料转化、死亡率、血清生化参数以及组织病理学等方面研究结果表明,饲料中添加3.0－5.0mg/kg剂量马杜霉素对肉鸡是安全的,未见任何毒副作用,而7.0-9.0mg/kg剂量则引起肉鸡中毒,中毒表现为,增重和饲料转化率明显下降,血清AST异常升高,心脏和肝脏出现病理变化。残留消除研究表明,马杜霉素主要残留于肉鸡的脂肪和肝脏,其次是肾脏,肌肉中残留最少。马杜霉素以5.0mg/kg剂量添加于饲料中饲喂肉鸡,停药2－3d,肉鸡组织中马杜霉素的残留量低于最高残留限量的规定。.     

海南霉素和泰妙菌素联合应用对雏鸡血液中微量元素的影响

<正>海南霉素是我国研制成功的第一个聚醚类抗生素,它具有良好的抗球虫作用,是当今最常用的防球虫药物添加剂,而泰妙菌素是最好的防治呼吸道病的药物之一。两种药物单独应用养禽业时本身都是安全的,但由于鸡球虫病与呼吸道病常同时发生,故两者需要联合应用。尽管两种药物联合应用使鸡中毒的病例多有报道,但其详细的病理变化及发病机制缺乏系统观察、研究。为探讨两种药物联合应用所引起雏鸡中毒的剂量及发病机制,试验选取海南霉素与泰妙菌素联合应     

几种药物抗小鼠弓形虫感染的初步效果

为寻找有效的抗弓形虫药物,选择了临床上使用较多的6种药物进行抗小鼠弓形虫感染初步实验。用刚地弓形虫（Toxoplasma gondii）长宁株（CN株）速殖子,按1×104/鼠腹腔接种昆明系雄性小白鼠,接种后4 h用药组通过灌服或饮水用药,每鼠剂量分别为阿奇霉素（Azithromycin）150、120、90 mg/（kg·d）,泰妙菌素（Tiamulin）100 mg/（kg·d）,克拉霉素（Clarithromycin）15 mg/（kg·d）,磺胺氯吡嗪钠（Sulfachloropyrazine sodium）150、120、90 mg/（kg·d）,甲硝唑（Metronidazole）150 mg/（kg·d）,甲氧苄胺嘧啶（Trimethoprim）10 mg/（kg·d）,连续用药5~6 d,接种后10 d结束实验。结果阿奇霉素、磺胺氯吡嗪钠组的平均存活天数明显高于感染不用药组（P〈0.05）,泰妙菌素、克拉霉素、甲硝唑、甲氧苄胺嘧啶组在所用剂量下的存活天数与感染不用药组无明显差异（P〉0.05）;用药后4－7 d,取腹腔液镜检速殖子,与感染不用药组相比,阿奇霉素组减少70%以上,磺胺氯吡嗪钠组减少99%以上。研究结果提示,磺胺氯吡嗪钠具有良好的抗弓形虫效果,其推荐剂量与用药疗程还有待进一步研究。     

柔嫩艾美耳球虫交叉抗药性试验

以雏鸡为试验对象,以抗球虫指数(ACI)为判断指标,检测5 mg/kg马杜霉素,70 mg/kg盐霉素,1 mg/kg 地克珠利对抗盐霉素株、抗地克珠利株和实验室保存的敏感株的控制效果。结果表明,马杜霉素对3 个虫株都有很好的抑杀效果,地克珠利也可有效地控制抗盐霉素株,同时,盐霉素也可有效地控制抗地克珠利株,说明盐霉素和地克珠利2种药物之间没有交叉抗药性。     

Investigation of pharmacokinetic parameters of tiamulin after intramuscular and subcutaneous administration in normal dogs

Laber, G. Investigation of pharmacokinetic parameters of tiamulin after intramuscular and subcutaneous administration in normal dogs. J. vet. Pharmacol. Therap. 11 , 45–49.
Kinetic variables for tiamulin in the normal dog have been determined. Serum concentrations of tiamulin were compared after intramuscular (i.m.) and subcutaneous (s.c.) administration of a single dose of tiamulin. Following a single i.m. dose of 10 mg/kg body weight, the compound was calculated to have a C_max= 0.61 ± 0.15 μg/ml, a T _max= 6 h and a t _½= 4.7 ± 1.4 h. Tiamulin showed dose-dependent pharmacokinetics when given as a single s.c. dose of either 10 mg or 25 mg/kg body weight. For the lower dose, the values C_max= 1.55 ± 0.11 μg/ml, T _max= 8 h and 1 _max= 4.28 ± 0.18 h were obtained. For the higher dose C _max= 3.14 ± 0.04 μg/ml, T _max= 8 h and t _½= 12.4 ± 3.4 h were calculated. When tiamulin was administered subcutaneously at a dose rate of 10 mg/kg body weight, higher and better maintained serum levels were achieved than those following i.m. administration. After repeated s.c. doses no significant accumulation of tiamulin occurred. Assuming that a continuous effective serum concentration is necessary throughout the course of therapy, these data would indicate that tiamulin should be given every 24 h.     

Studies on the toxic interaction between monensin and tiamulin in rats: toxicity and pathology

The characteristics of the toxic interaction between monensin and tiamulin were investigated in rats. A three-day comparative oral repeated-dose toxicity study was performed in Phase I, when the effects of monensin and tiamulin were studied separately (monensin 10, 30, and 50 mg/kg or tiamulin 40, 120, and 200 mg/kg body weight, respectively). In Phase II, the two compounds were administered simultaneously to study the toxic interaction (monensin 10 mg/kg and tiamulin 40 mg/kg b.w., respectively). Monensin proved to be toxic to rats at doses of 30 and 50 mg/kg. Tiamulin was well tolerated up to the dose of 200 mg/kg. After combined administration, signs of toxicity were seen (including lethality in females). Monensin caused a dose-dependent cardiotoxic effect and vacuolar degeneration of the skeletal muscles in the animals given 50 mg/kg. Both compounds exerted a toxic effect on the liver in high doses. After simultaneous administration of the two compounds, there was a mild effect on the liver (females only), hydropic degeneration of the myocardium and vacuolar degeneration of the skeletal muscles. The alteration seen in the skeletal muscles was more marked than that seen after the administration of 50 mg/kg monensin alone.     

Monensin toxicosis in swine: potentiation by tiamulin administration and ameliorative effect of treatment with selenium and/or vitamin E

Modulation of acute monensin toxicosis in swine was evaluated in 2 studies. In study 1, 56 weanling male pigs were allotted to 14 groups of 4 each. Pigs in 7 groups were given tiamulin in the drinking water (to supply 7.7 mg/kg of body weight/day) for 3 days before and for 2 days after monensin administration. Monensin was given as a single oral dose (at 0, 7.5, 15, 25, 50, 75, or 100 mg/kg) to pigs in groups with or without tiamulin exposure. Prominent acute clinical signs of monensin toxicosis (hypermetria, hind limb ataxia, paresis, knuckling of hind limbs, and recumbency) developed by 2 to 6 hours after dosing in pigs given 15 or 25 mg of monensin/kg with tiamulin exposure, but not in pigs given the 15 or 25 mg of monensin/kg without tiamulin exposure. Also, the extent of monensin-induced skeletal muscle damage at 4 days after monensin dosing was enhanced in pigs given 7.5, 15, or 25 mg of monensin/kg and exposed to tiamulin. In study 2, 48 weanling male pigs were allotted to 8 groups of 6 each. Four groups of pigs were given 20 mg of monensin/kg orally, and 4 groups were given 100 mg of monensin/kg orally. For each monensin dose, a group was treated 24 hours before monensin administration with (i) selenium (Se)-vitamin E preparation, 0.25 mg of Se and 68 IU of d-alpha-tocopheryl acetate (vitamin E)/kg, IM; (ii) vitamin E only, 68 IU of d-alpha-tocopheryl acetate/kg; (iii) Se only, 0.25 mg of Se/kg; or (iv) vehicle.(ABSTRACT TRUNCATED AT 250 WORDS)     

'Pink eye' or 'zere oogjes' or keratoconjunctivitis infectiosa ovis (KIO). Clinical efficacy of a number of antimicrobial therapies

In a comparative study the clinical efficacy of five different treatments of keratoconjunctivitis infectiosa ovis (KIO) were tested, namely an intramuscular injection of chloramphenicol base (dosage 15 mg/kg), spiramycin base (Suanovil dosages 10 to 25 mg/kg), oxytetracycline (Engemycine Forte, Terramycin LA, dosages respectively 5 and 10 mg/kg), tiamulin (Dynamutulin, dosage 10 mg/kg) and subcutaneous injection of procaine penicillin G, benzathine penicillin G. and dihydrostreptomycin in the lower eyelid. It appeared from these field trials that spiramycin base, oxytetracycline and tiamulin had a clearly positive effect on the clinical course of 'pink eye', although with tiamulin there was only a temporary effect (high percentage of relapses). In view of the field data the following dosage schemes are, for the time being, advised: spiramycin base (Suanovil), and oxytetracycline (formulation with a good biological availability) both 20 to 30 mg/kg and, if necessary, to be repeated on days 5 and 10 after the first intramuscular injection. The dosage scheme advised for tiamulin is 20-30 mg/kg to be repeated on day 3 and if necessary on days 6 and 9 after the intramuscular injection. In mild cases it is sufficient to rub the eyes with for example oxytetracycline eye-ointment, a few times a day.     

Studies on the toxic interaction between monensin and tiamulin in rats: effects on P450 activities

Studies were carried out to investigate the effects of monensin and tiamulin, and the simultaneous administration of both compounds on microsomal enzymes in rats. In Phase I of the experiments the effects of monensin and tiamulin were studied separately (monensin 10, 30, and 50 mg/kg or tiamulin 40, 120, and 200 mg/kg body weight, respectively), while in Phase II the two compounds were administered simultaneously (monesin 10 mg/kg and tiamulin 40 mg/kg b.w., respectively). When monensin was administered by itself, it exerted no significant effect on microsomal liver enzymes. In a few cases, slight inhibition of certain enzyme activities was seen. Tiamulin provoked a dose-dependent hepatic enzyme induction. The combined administration of monensin and tiamulin at low doses (10 and 40 mg/kg, respectively) resulted in marked elevation of P450-related enzyme activities. The enzyme induction was more pronounced in females than in males. The results suggest that the simultaneous administration of tiamulin may influence the biotransformation of monensin, possibly increasing the amount of reactive metabolite(s) of the ionophore antibiotic.     

‘Pink eye’ or ‘zere oogjes’ or Keratoconjunctivitis Infectiosa Ovis (KIO)

In a comparative study the clinical efficacy of five different treatments of keratoconjunctivitis infectiosa ovis (KIO) were tested, namely an intramuscular injection of chloramphenicol base (dosage 15 mg/kg), spiramycin base (Suanovil^® dosages 10 to 25 mg/kg), oxytetracycline (Engemycine^® Forte, Terramycin^® LA, dosages respectively 5 and 10 mg/kg), tiamulin (Dynamutulin^®, dosage 10 mg/kg) and subcutaneous injection of procaine penicillin G, benzathine penicillin G, and dihydrostreptomycin in the lower eyelid.

It appeared from these field trials that spiramycin base, oxytetracycline and tiamulin had a clearly positive effect on the clinical course of ‘pink eye’, although with tiamulin there was only a temporary effect (high percentage of relapses).

In view of the field data the following dosage schemes are, for the time being, advised: spiramycin. base (Suanovil^®), and oxytetracycline (formulation with a good biological availability) both 20 to 30 mg/kg and, if necessary, to be repeated on days 5 and 10 after the first intramuscular injection. The dosage scheme advised for tiamulin is 20–30 mg/kg to be repeated on day 3 and if necessary on days 6 and 9 after the intramuscular injection. In mild cases it is sufficient to rub the eyes with for example oxytetracycline eye‐ointment, a few times a day.     

Effect of tiamulin administered by various methods and dosages on turkeys at different ages

Healthy male turkeys not receiving monensin in their feed were treated with tiamulin by various methods and at different ages. Nine cycles of treatments were performed at the ages of 26, 40, 61, 89, 103, 117, 131, 145, and 160 days. Intramuscular of subcutaneous injections of 12.5 mg/kg tiamulin up to 145 days did not result in any signs of toxicity or impair growth rate. Administration at a dose of up to 25 mg/kg, using the drinking-water-deprivation technique, caused no effect in turkeys up to 160 days (marketing age).     

Use of tiamulin in a herd of pigs seriously affected with Mycoplasma hyosynoviae arthritis

Tiamulin hydrogen fumarate has been shown to be highly active in vitro against Mycoplasma hyosynoviae, an organism that causes arthritis in pigs. A gilt-multiplier herd with a history of this condition was selected to evaluate the efficacy of tiamulin in vivo for the treatment of this disease. The presence of M hyosynoviae was confirmed by its isolation from two typically affected cases. A field trial was carried out on clinically affected pigs, using tiamulin at 10 mg and 15 mg/kg bodyweight given by injection for three consecutive days, by comparing their weight gains and reduction in lameness scores during a seven day trial period (days 0 to 7) with those of negative untreated controls and positive controls injected with lincomycin at 10 mg/kg bodyweight for three days. Both of the tiamulin treatment levels appeared to be effective, as there were marked improvements in weight gains and reduction in lameness scores in comparison with the negative controls. The improvements were similar to those achieved with the positive control, lincomycin.     

The effect of tiamulin administered by different routes and at different ages to turkeys receiving monensin in their feed

Healthy turkeys receiving 80 ppm monensin in their feed were injected at 26, 40 and 61 days of age with tiamulin at dosages of 12.5 and 25 mg/kg body weight. The aim of the study was to develop a regime for medicating with tiamulin turkeys receiving monensin in their feed, and which would circumvent the known toxicity created by the simultaneous administration of the two drugs. One injection of 12.5 mg/kg tiamulin up to the age of 61 days or 2 injections of 12.5 mg/kg tiamulin up to 40 days of age caused no mortality or adverse reaction.