Effect of avoparcin interaction with anticoccidial compounds on the growth and carcase composition of broilers

The anticoccidial drugs narasin, lasalocid, monensin and salinomycin, with and without avoparcin, were fed to 1280 broiler chickens from 1 to 49 d old. At day 49 significant interactions were detected between avoparcin and the anticoccidial compounds for body weight and food consumption. This indicated that the increases in body weight and food consumption obtained with avoparcin were greater with some anticoccidial compounds (lasalocid and salinomycin for body weights and lasalocid for food consumption) than with others (monensin and narasin for body weights and monensin, narasin and salinomycin for food consumption). Overall there was evidence that avoparcin increased body weight (5.8%), food consumption (2.5%) and efficiency of food utilisation (2.9%). In addition avoparcin produced significant increases in plucked weight and the proportion of visceral fat together with and decreases in the proportions of edible giblets and waste offal.     

柔嫩艾美耳球虫盐霉素耐药株的实验室诱导

为了研究耐药性柔嫩艾美耳球虫产生耐药性的机理,本研究在实验室条件下,采用药物浓度递增的方法,以15 mg/kg为起始诱导浓度,对柔嫩艾美耳球虫盐霉素耐药性进行诱导.经过10次传代,获得了对60 mg/kg盐霉素耐药的柔嫩艾美耳球虫虫株.以抗球虫指数、最适抗球虫活性百分率、病变记分减少率和相对卵囊产量四项指标综合判定柔嫩...     

柔嫩艾美耳球虫癸氧喹酯耐药株的诱导研究

采用药物浓度递增法,在实验室条件下进行柔嫩艾美耳球虫耐药虫株的诱导。以5.4 mg/kg癸氧喹酯为起始诱导浓度连续传代,以病变记分减少率(RLS)、最适抗球虫指数(POAA)和抗球虫指数(ACI)3项指标综合判定耐药性,经9次传代,成功地诱导出对54 mg/kg癸氧喹酯具有完全抵抗力的耐药虫株,为进一步的球虫耐药的分子机理研究提供材料。     

Relative value of oocyst counts in evaluating anticoccidial activity.

Birds medicated with roxarsone and in another experiment with zoalene in the feed produced higher oocysts counts than unmedicated control birds receiving the same oocyst dose of Eimeria tenella or a mixture of six species (E. tenella, E. necatrix, E. brunetti, E. maxima, E. acervulina, and E. mitvati). These experiments confirm the conclusion that oocyst counts constitute an unsatisfactory and unreliable parameter for judging effectiveness of an anticoccidial even though such increases are a relatively rare occurrence in anticoccidial evaluation experiments.     

猪粪中洛克沙胂的HPLC检测及排泄规律

在建立猪粪中洛克沙胂HPLC检测方法基础上,选用24头育肥猪,分别混饲给予0、25、50、100 mg/kg洛克沙胂,混饲给药后不同时间采集粪样,以高效液相色谱法测定其中洛克沙胂质量浓度,了解洛克沙胂混饲给药后在猪体内的排泄情况,然后从江苏和山东省15个使用洛克沙胂的集约化猪场采集150头猪的粪样,调查猪粪样中的洛克沙胂含量。结果表明,所建立的猪粪中洛克沙胂HPLC检测方法的平均回收率为82.09%~84.03%,变异系数为2.92%~5.45%,检测限为0.05 mg/kg,定量限为0.1 mg/kg;以不同剂量混饲给药后,洛克沙胂在粪中排泄量在36~48 h达峰,峰质量浓度分别为12.31、22.52、34.78 mg/kg,猪粪中检测不到洛克沙胂的时间分别为72、108、132 h;所调查150个粪样中洛克沙胂平均质量浓度为23.13 mg/kg。     

Toxic effects of supplemental copper and roxarsone when fed alone or in combination to young pigs

Three experiments were conducted to investigate the roxarsone (3-nitro-4-hydroxyphenylarsonic acid) X copper (Cu) interaction in weanling pigs. Supplemental roxarsone at 400 mg/kg diet decreased rate and efficiency of weight gain and caused visible neurological signs of toxicosis. Copper addition (CuSO4 X 5H2O) at a level of 650 mg Cu/kg diet likewise decreased weight gain and feed efficiency, and it also increased hepatic Cu deposition. The combination of these growth-depressing dosages of roxarsone and Cu resulted in a far greater reduction in gain and efficiency of feed utilization than was the case when either compound was fed alone. A growth-promoting dosage of Cu (250 mg/kg) increased weight gain by 32% in one experiment but showed no efficacy in alleviating the growth-depression resulting from feeding 400 mg/kg roxarsone. A roxarsone dosage of 100 mg/kg increased gain and feed efficiency. Surprisingly, the decreased weight gain in pigs fed 650 mg/kg Cu was ameliorated by feeding 100 mg/kg roxarsone concomitantly. This level of roxarsone also reduced liver Cu concentration substantially. It thus appears that the nature of the roxarsone X Cu interaction is dependent on the dose of each compound administered. Moreover, low-dose roxarsone administration appears to ameliorate Cu toxicity, but low-dose Cu feeding does not show efficacy against roxarsone toxicity.     

Isolation and selection of ionophore-tolerant Eimeria precocious lines: E. tenella, E. maxima and E. acervulina

Eimeria parasites were isolated from Nanhai Guangdong province (southern China) and studied in chickens in wire cages to evaluate their drug resistance against commonly used ionophores: monensin (100 mg/kg of feed), lasolacid (90 mg/kg), salinomycin (60 mg/kg), maduramicin (5 mg/kg) and semduramicin (25 mg/kg). Chinese Yellow Broiler Chickens were infected with 40,000 crude sporulated Eimeria oocysts at 15 days of age and prophylactic medication commenced a day prior to infection. Drug resistance was assessed for each ionophore drug by calculating the anticoccidial index (ACI) and percentage optimum anticoccidial activity (POAA) based on relative weight gain, rate of oocyst production and lesion values. Results revealed that Nanhai Eimeria oocysts comprising of E. tenella, E. maxima and E. acervulina, were resistant to monensin, sensitive to both salinomycin and lasolacid and partially sensitive to maduramicin and semduramicin. By selection for early development of oocysts during passage through chickens, the prepatent time of E. tenella, E. maxima and E. acervulina were reduced by 49, 36 and 22 h, respectively. The precocious lines are less pathogenic than the parent strains from which they were selected and conferred a satisfactory protection for chickens against coccidiosis. These ionophore-tolerant precocious lines could have wider applications in the development of anticoccidial vaccines for sustainable control of coccidiosis.     

复方尼卡巴嗪、马杜霉素铵对鸡艾美耳球虫临床防治效果初探

试验表明,推荐量的复方尼卡巴嗪（125mg／kg）、马杜霉素铵（5mg／kg）对E．tenella GD珠球虫抗球虫指数为194．1,对6个E．tenella 田间分离株抗球虫指数都在170以上,其抗球虫指数优于单方的尼卡巴嗪及马杜霉素组,尤其对耐药虫株。     

Influence of dietary enzyme complex on the performance of broilers fed on diets with and without antibiotic supplementation

1. The aim of the experiment was to test the possible interactions of an enzyme complex and a food antibiotic on the growth and metabolism, carcase yield, whole body composition and nutrient deposition in broilers. The basal diet contained 400 g/kg barley. The four treatments were as follows: O—without supplements (control), E—enzyme complex Roxazyme® G, 200 mg/kg, A—antibiotic avoparcin, 10 mg/kg, EA—Roxazyme G, 200 mg/kg plus avoparcin, 10 mg/kg.

2. Roxazyme G positively influenced weight gain, food conversion efficiency, energy metabolisability, fat and nitrogen utilisation and the dry matter content of droppings. Fat and energy deposition in the whole body were also increased, whereas protein deposition and carcase yield were not influenced.

3. Avoparcin increased energy metabolisability and fat utilisation, but had no influence on nitrogen utilisation. No significant improvements from avoparcin were seen in growth or in nutrient deposition in the body. The fibre degradability (NDF and ADF fraction) was significantly depressed by antibiotic supplementation.

4. The inclusion of both supplements to the diet did not have a fully additive effect on growth, energy metabolisability, or fat and nitrogen utilisation. The interaction between enzyme and antibiotic for food conversion efficiency during the first experimental period (7 to 21 d) was nearly significant (P= 0.053). Except for fibre degradability (P ≤ 0.01), no other significant interactions between enzyme and antibiotic were found.     

Effect of roxarsone inclusion in the diet on the performance and hepatic lipid metabolism of laying Tsaiya duck

1. The aim of this study was to examine the effects of roxarsone (3-nitro-4-hydroxyphenylarsonic acid) inclusion in the diet on the performance, liver function and lipid metabolism in the liver of laying Brown Tsaiya ducks. 2. Sixty 36-week-old laying ducks were selected and allocated at random into 4 dietary treatments with 3 replications for each treatment. Feeding was for 7 weeks with 3 weeks of experimental diets followed by a 4 week withdrawal period. The experimental diets were supplemented with 0, 50, 100 and 300 mg/kg roxarsone, respectively 3. Dietary inclusion of 50 or 100 mg/kg roxarsone did not significantly promote performance. Inclusion of 300 mg/kg significantly depressed (P<0.05) performance, liver weight and content, serum triacylglycerol (TG), serum nonesterified fatty acid (NEFA) and increased (P<0.05) cholesterol, creatine kinase (CK) and aspartate aminotransferase (AST) in the serum at the end of 3 weeks on the experimental diet. 4. Laying characteristics returned to normal 4 weeks after withdrawal of roxarsone. The liver weight, fat and TG in the liver and serum concentrations of TG, NEFA, high density lipoprotein (HDL) and AST increased significantly (P<0.05), while the level of very low density lipoprotein (VLDL) decreased (P<0.05) at the end of the withdrawal period. More prominent vacuolised hepatic fatty cells were observed in laying ducks treated with 300 mg/kg of roxarsone.     

The value of plant extracts with antioxidant activity in attenuating coccidiosis in broiler chickens

Coccidiosis remains one of the most important diseases in the poultry industry and results in the annual loss of millions of US dollars by the poultry industry. In South Africa and other developing countries where a large percentage of the population is unemployed, cheap food production is necessary. If the control of the coccidian parasite could be made more economical, these savings could be passed on to the consumer. In Europe, where the economics are different, people are becoming more aware of the potential dangers of using antimicrobials in producing animal protein. A solution to both these problems could be the use of plant products that function by mechanisms other than those of chemotherapeutics, with the additional advantage of a natural origin. Antioxidant compounds could hold promise for the control of Eimeria infections due to the association of coccidial infection with lipid peroxidation of the intestinal mucosa. Four plant extracts with antioxidant activity were screened for their anticoccidial activity in vivo with toltrazuril as the positive control. Combretum woodii (160 mg/kg) proved to be extremely toxic to the birds, while treatment with Tulbaghia violacea (35 g/kg), Vitis vinifera (75 mg/kg) and Artemisia afra (150 mg/kg) resulted in feed conversion ratios similar to toltrazuril, and higher than the untreated control. T. violacea also significantly decreased the oocyst production in the birds. From this study we conclude that antioxidant-rich plant extracts have potential benefits in treating coccidial infections. The promising results obtained with T. violacea justify further studies on the potential value of the plant as a therapeutic or prophylactic anticoccidial agent.     

In-vitro antimicrobial susceptibility of Clostridium perfringens from commercial turkey and broiler chicken origin

The minimum inhibitory concentrations (MIC) of eight antibiotics and two anticoccidial agents were determined for Clostridium perfringens strains isolated from 26 commercial broiler farms and 22 commercial turkey farms. Isolates were obtained from the intestines of birds on the farm or at the processing plant using standard culture and identification techniques. The microbroth dilution test was used to determine the MIC for each compound. Most isolates from chickens had MICs in the range of 2–16 mg/L for tilmicosin, tylosin and virginiamycin, whereas the MICs for avilamycin, avoparcin, monensin, narasin and penicillin were ≤1 mg/L. Most strains from chickens had high MICs (≥64 mg/L) and appeared to be resistant to bacitracin and lincomycin. Most turkey isolates had MICs in the range of 2–16 mg/L for bacitracin, tilmicosin, tylosin and virginiamycin, with strains exhibiting MICs ≤ 1 mg/L for avilamycin, avoparcin, monensin, narasin and penicillin. Several turkey isolates had MICs ≥ 64 mg/L to lincomycin. No attempt was made to associate farm usage of a particular antibiotic to the antibiograms.     

Arsenic-sulfur amino acid interactions in the chick

Experiments were conducted with growing crossbred chicks to determine the reasons why cysteine exacerbates roxarsone (3-nitro-4-hydroxyphenylarsonic acid) toxicity. A fortified corn-soybean meal diet that met or exceeded all nutrient requirements of the young chick was fed. While cysteine enhanced roxarsone toxicity, it had little effect on the toxicity of the inorganic arsenicals As2O3 and As2O5. The toxicity of another pentavalent organic arsenical, phenylarsonic acid, was also exacerbated by cysteine. In contrast, the growth-depression resulting from feeding the trivalent form of phenylarsonic acid, i.e., phenylarsine oxide, was not affected by dietary addition of cysteine. Supplementation of the diet with cystine, methionine or K2SO4 did not exacerbate roxarsone toxicity. Reduced glutathione (GSH), however, slightly increased the gain/feed depression resulting from feeding 300 mg roxarsone/kg diet. When injected ip 1) roxarsone and cysteine, or 2) roxarsone and ascorbic acid killed 100 or 60% of the birds, respectively, within 48 h postinjection. Few (6.7%) deaths resulted from ip injections of the same level of roxarsone alone. Therefore, the potentiation of toxicity requires pentavalent organic arsenicals and compounds that can act as reducing agents. We concluded that cysteine exacerbates roxarsone toxicity by reducing it to the more toxic trivalent state.     

抗鸡球虫病的三嗪类新化合物纳川珠利的药效试验

采用抗鸡柔嫩艾美尔球虫实验室笼养试验模型,对新合成的三嗪化合物纳川珠利进行了2批次的抗球虫活性试验。结果显示,纳川珠利添加剂量5、10和30 mg/kg时,抗球虫指数均大于180。添加剂量1和3 mg/kg时,见有少量血便和盲肠病变,抗球虫活性介于中效和高效之间。表明纳川珠利是一种高效安全的新型三嗪类抗球虫化合物,推荐使用剂量以3~5 mg/kg为宜,有望开发成为一种新的抗球虫药物。     

柔嫩艾美耳球虫对盐酸氟乙基硫胺素耐药性的诱导

为评估盐酸氟乙基硫胺素产生抗药性的倾向,采用药物浓度递增法,在实验条件下进行柔嫩艾美耳球虫耐药性的诱导研究。每组动物用10只快大黄肉鸡,每只鸡接种1×105个孢子化卵囊,以50 mg/kg盐酸氨丙啉和盐酸氟乙基硫胺素为起始诱导浓度连续传代,以病变记分、存活率和卵囊数三项指标综合判定耐药性。经过10次传代,盐酸氨丙啉对敏感虫株的ACI为192.6,而对耐药虫株的ACI为109.1;经过12次传代,盐酸氟乙基硫胺素对敏感虫株的ACI为197.5,而对耐药虫株的ACI为110.6,对盐酸氨丙啉耐药虫株的ACI为163.2;结果表明成功地诱导出对盐酸氨丙啉、盐酸氟乙基硫胺素完全耐药的虫株。盐酸氟乙基硫胺素产生耐药速度慢于盐酸氨丙啉,与盐酸氨丙啉有部分交叉耐药性。     

一毒害艾美耳球虫田间分离株耐药性分析

用鸡体实验法,以相对卵囊产量(ROP)、病变记分减少率(RLS)、最适抗球虫百分数(POAA)和抗球虫指数(ACI)等4项指标,分析了一株毒害艾美耳球虫对复方磺胺氯吡嗪钠(20％磺胺氯吡嗪钠+4％二甲氧苄啶)、血痢宁(磺胺氯吡嗪钠可溶性粉)、贝尔球康(又称鸡球虫散,含青蒿、仙鹤草、何首乌、白头翁、肉桂等)、百球清(妥曲珠利)、马杜球败(马度米星铵预混剂)等5种抗球虫药的耐药性.结果显示:该株毒害艾美耳球虫对百球清无耐药性,对复方磺胺氯吡嗪钠和血痢宁有轻度耐药性,对贝尔球康无耐药性或轻度耐药性,对马杜球败有完全耐药性.提示该养殖场应停止使用马杜拉霉素,改用妥曲珠利或贝尔球康,但必须进行轮换用药或联合用药,以延长药物的使用寿命.     

The effect of avoparcin on apparent digestibility, characteristics of rumen fermentation and fattening and slaughter output of growing cattle

Four digestion experiments with 5 wethers each (0, 15, 30 or 60 mg avoparcin per animal and day), three individual feeding experiments (28, 18 or 56 bulls per experiment; 0 and 150/200; 0, 250 and 500 or 0 and 200 mg avoparcin per animal and day in the experiments 1, 2 or 3) and two group feeding experiments (60 bulls and 161 heifers per experiment; salt lick stones without or with 2.5 g avoparcin per kg) were carried out in order to investigate the influence of avoparcin on apparent digestibility, figures of rumen fermentation, fattening and slaughtering results as well as protein, fat and energy retention. Avoparcin supplementation did not significantly influence the apparent digestibility of organic matter and crude nutrients. Concentration of acetate of rumen liquid was decreased (16 or 36) and that of propionate was increased (25 or 50 mmoles per mol) when 200 or 500 mg avoparcin per animal and day were added. Acetate:propionate ratio decreased from 4.2 to 3.5 and 3.1:1. Avoparcin did not influence feed intake, enhanced daily weight gain (37 to 174 g per animal and day) and improved feed efficiency (5 to 26%). Salt lick stones with avoparcin increased weight gain (58 and 96 g per animal and day). Slaughtering results and body composition of bulls were not influenced by avoparcin. Daily retention of protein, fat and energy was significantly increased (16 to 18%; P less than 0.05) when avoparcin was supplemented.     

腐霉素的安全性及药效研究

本文报道了腐霉素钠盐的安全性及药效的研究成果,包括大、小鼠及雏鸡急性毒性试验、蓄积毒性及耐受性试验、肉鸡喂养试验和药效试验。本研究的初步结果表明,腐霉素钠盐做为一种新的聚醚类抗球虫药物添加剂安全有效,最适宜的混料浓度为160ppm。     

三种抗球虫药对鸡球虫病的对比疗效

为评价药物阿德呋啉对艾美耳球虫的治疗效果,本试验设70 mg/kg阿德呋啉组、121mg/kg莫能菌素组和125 mg/kg尼卡巴嗪组3个药物试验组,以及阳性和阴性对照组。除阴性对照组外,其余全部试验鸡每只接种球虫孢子化卵囊5.2万个,根据成活率、相对增重率、卵囊值、病变值计算抗球虫指数(Anticoccidial Index,ACI),进而判定药物的疗效。结果显示,121 mg/kg莫能菌素组ACI为115.6,在120以下,不宜作抗球虫药;125 mg/kg尼卡巴嗪组ACI为137.2,在120～160之间,抗球虫效力低;70 mg/kg阿德呋啉组ACI为192.9,为高效抗球虫药。     

Roxarsone (3-nitro-4-hydroxyphenylarsonic acid) poisoning in pigs

Young pigs, six to ten weeks of age, from two unrelated swine operations were fed a grower ration obtained from a common commercial supplier. Following ingestion of the feed for approximately two weeks, pigs in both groups developed neurological disturbances characterized by blindness, ataxia, incoordination, muscle tremors, posterior paralysis, and quadriplegia. Vocalization described as “screaming” was also observed in several animals. Necropsy findings and tissue arsenic concentrations were consistent with a diagnosis of phenylarsonic acid poisoning. The liver and kidney contained an average arsenic content of 2.9 and 1.8 mg/kg (wet weight), respectively. The feed contained 38 mg of arsenic/kg corresponding to 133 mg roxarsone (3-nitro-4-hydroxyphenylarsonic acid)/kg. This level of roxarsone is approximately three to five times higher than the levels recommended for swine rations. The feed company had placed roxarsone in the ration at levels recommended for the less toxic arsanilic acid. It was assumed that the two organic arsenicals could be added to the rations interchangeably at the same level of formulation. The present investigation indicated that roxarsone is more toxic than arsanilic acid and the margin of safety in swine rations is low.