优素精~和盐霉素之笼饲药效试验

优素精￣（日本科研制药株式会社制品）和盐霉素（山东济宁抗生素厂制品）之抗球虫效力的比较试验。１４日龄艾维因肉鸡分４组；Ⅰ、盐霉素组；Ⅱ、优素精组；Ⅲ、感染不给药对照组；Ⅳ、不感染不给药对照组。每组６笼，每笼１０只（公母各５只）。优素精和盐霉素均以６０ｐｐｍ之浓度混合于饲料中，自由摄食。１６日龄时，Ⅰ、Ⅱ、Ⅲ组分别经口感染Ｅ．ａｃｅｒｖｕｌｉｎａ，Ｅ．ｍａｘｉｍａ和Ｅ．ｔｅｎｅｌｌａ混合卵囊，每鸡１０．１２×１０￣４。２３日龄（感染后７天）解剖全部鸡。依增重，饲料利用效率，血粪，卵囊排出量，球虫病变值和球虫病死亡率判断抗球虫效力。试验结果：优素精组的平均增重（２７０．０８克）和饲料利用率（２．０３）是试验各组中最优良的。比不感染不给药对照组优越，生物统计差异显著（Ｐ＜０．０１）。盐霉素组的平均增重（２６２．４２克）和饲料利用率（２．０８）虽高于不感染不给药对照组，但其差异不显著（Ｐ＞０．０５）。优素精组的球虫病变值比感染不给药对照组低４６．４０％，比盐霉素组低３６．２９％，卵囊排出量比感染不给药对照组低９７．２５％，比盐霉素组低２０．０４％。本试验证明，优素精有强烈的抗球虫药效，同时也证明有促进生长，加速增重?     

Drug-sensitivity of 99 isolates of coccidia from broiler farms

Coccidia were isolated from 99 broiler farms in 12 broiler-producing states and tested for sensitivity to contemporary anticoccidial drugs. The isolates usually comprised two or more species, including 92 Eimeria acervulina, 47 E. maxima, 28 E. tenella, and 10 E. brunetti. Based on intestinal-lesion-score reduction of 30% or more, 38% of isolates were resistant to monensin (110 ppm), 29% to salinomycin (60 ppm), 20% to nicarbazin (125 ppm), and 46% to amprolium + ethopabate (125 + 4 ppm). Isolates with 50% or greater reduction of lesion scores were considered sensitive. Thirty-three percent were sensitive to monensin, 53% to salinomycin, 67% to nicarbazin, and 39% to amprolium + ethopabate. Other isolates had intermediate response to drugs and were considered to have "reduced sensitivity." There was some evidence for incomplete cross resistance to the polyether, ionophorous products.     

Study of resistance against some ionophores in Eimeria tenella field isolates.

Three Eimeria tenella field isolates from Gurgaon district of Haryana (north India) were studied in a battery test for evaluating drug resistance against two currently used ionophores; maduramicin (5ppm) and salinomycin (60ppm). Broiler birds (Ross strain) were infected with 10(5) sporulated oocysts each at the age of 2 weeks and prophylactic medication commenced 2 days prior to infection. Drug resistance was assessed by calculating the global index for individual ionophore compounds based on weight gain, feed conversion ratio, oocyst index, lesion score and mortality. Present studies revealed no resistance of the ionophores in any of the field isolates. Both the drugs showed varying degree of efficacy, e.g. maduramicin exhibited limited efficacy against all the three field isolates, whereas salinomycin showed limited efficacy against Gurgaon isolate (GrI)-I, good efficacy against GrI-II and partial resistance against GrI-III.     

Identification of Cross-Resistance and Multiple Resistance in Eimeria tenella Field Isolates to Commonly Used Anticoccidials in Pakistan

A battery trial was conducted to evaluate the drug sensitivity in Eimeria tenella field isolates against the commonly used anticoccidials salinomycin (60 ppm), maduramicin (5 ppm), and clopidol (125 ppm) in broiler chicks. These anticoccidials were mixed in feed at d 12 of age, and inoculation was given on d 14 of age. Drug sensitivity was determined by using the global index, which is composed of percentage weight gain, FCR, lesion score, oocyst index, and mortality percentage. In the present study, all the E. tenella isolates showed partial resistance against salinomycin, whereas varying degrees of sensitivity were observed against maduramicin and clopidol.     

Efficacy of tiamulin as a growth promotant for growing swine

A study involving 244 pigs initially averaging 13 kg was conducted at two stations to evaluate tiamulin as a growth promotant for growing swine. In each experiment, four replicate pens of five (Exp. 1) or six (Exp. 2) pigs/pen were used to evaluate each treatment. In Exp. 1, pigs were fed 0, 11, 22 or 44 ppm tiamulin from 15 to 58 kg, then fed a nonmedicated control diet for the remainder of the experiment (to 95 kg). In Exp. 2, pigs were fed 0, 2.75, 5.5, 11 or 22 ppm tiamulin from 11 to 56 kg, followed by the nonmedicated control diet (to 95 kg). In each experiment, carbadox (55 ppm) was included as a positive control and was fed to an average weight of 35 kg, followed by the control diet. Averaged across all dietary levels, tiamulin resulted in a 14.1% improvement in gain and a 5.7% improvement in feed:gain ratio during the first 28 to 35 d of the experiment (to 30 kg). These improvements were slightly less than those resulting from the feeding of carbadox during the same period (21.5 and 6.9%, respectively). From 13 to 57 kg, pigs fed tiamulin gained 11.6% faster and 3.1% more efficiently than did controls. Over the entire experiment (13 to 95 kg), tiamulin-fed pigs gained 5.7% faster than did controls, even though the tiamulin was withdrawn at 57 kg body weight. Growth rate from 13 to 57 kg plateaued at the 11-ppm dietary level of tiamulin; whereas, feed:gain ratio plateaued at the 22-ppm level. The results indicate that tiamulin is an effective growth promotant for growing swine.     

Effect of acute salinomycin-tiamulin toxicity on the lipid peroxide and antioxidant status of broiler chicken.

The combined effect, if any, of salinomycin poisoning and salinomycin-tiamulin interaction on lipid-peroxidative processes and the antioxidative defence system of the liver was studied in domestic fowl. Male broilers (28-day-old), reared on a diet containing 60 mg/kg salinomycin, were treated intraoesophageally with salinomycin (140 mg/kg body mass) or tiamulin (50 mg/kg body mass). Malondialdehyde, reduced glutathione and cytochrome P-450 concentrations as well as glutathione peroxidase and catalase activities of the liver were determined. Liver malondialdehyde concentration rose in the salinomycin-treated group while the amount of cytochrome P-450 increased in both groups treated. Glutathione concentration and glutathione peroxidase activity of the liver decreased rapidly but hepatic catalase activity increased in both groups after the treatment. Manifestation of the effect exerted by salinomycin and salinomycin-tiamulin on lipid-peroxidative processes nearly coincided with the onset of clinical signs and preceded the increase of hepatic cytochrome P-450 concentration. According to the results, the background of the previously reported incompatibility between salinomycin and tiamulin is the synergistic effect exerted on the antioxidant (glutathione) system.     

Effect of salinomycin level on nutrient digestibility and ruminal characteristics of sheep and feedlot performance of cattle

A sheep digestion trial and two feedlot trials with cattle were conducted to study effects of an ionophore, salinomycin, on nutrient digestibility, ruminal metabolism and cattle performance. In trial 1, addition of salinomycin at 5.5, 11 or 22 ppm to 60% concentrate diets fed to ruminal-cannulated rams had no effect (P greater than .05) on apparent digestibility of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) or starch in comparison with control diets. Apparent nitrogen (N) digestibility was increased (P less than .05) in animals fed salinomycin. Salinomycin did not affect total volatile fatty acid (VFA) concentrations in the rumen, but resulted in a linear (P less than .05) increase in molar proportion of propionate and a linear (P less than .05) decrease in molar proportions of acetate and butyrate and in acetate:propionate ratios. Shifts in VFA proportions were fully expressed within 4 d after salinomycin was added to the diet. In trial 2, salinomycin was added at 5.5, 11, 22 or 33 ppm to 85% concentrate diets fed to finishing steers. Salinomycin level had a quadratic effect (P less than .05) on daily weight gain and resulted in a quadratic (P less than .05) decrease in feed intake with a resultant average improvement of 10.3% in feed efficiency. Salinomycin (5.5, 11, 16.5 or 22 ppm) and monensin (22 ppm) were added to 90% concentrate diets in trial 3 and produced increased rates of gain without affecting feed intake.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the oral bioavailability and tissue disposition of monensin and salinomycin in chickens and turkeys

Henri, J., Maurice, R., Postollec, G., Dubreil‐Cheneau, E., Roudaut, B., Laurentie, M., Sanders, P. Comparison of the oral bioavailability and tissue disposition of monensin and salinomycin in chickens and turkeys. J. Vet. Pharmacol. Therap.  35 , 73–81. The current study describes the pharmacokinetic parameters of two carboxylic polyether ionophores: monensin in turkeys and salinomycin in chickens. These data can be used to understand and predict the occurrence of undesirable residues of coccidiostats in edible tissues of these animal species. Special attention is paid to the distribution of residues between the different edible tissues during and at the end of the treatment period. For the bioavailability studies, monensin was administered to turkeys intravenously, in the left wing vein, at a dose of 0.4 mg /kg and orally at a dose of 20 mg /kg. Salinomycin was administered to chickens intravenously, in the left wing vein, at a dose of 0.25 mg /kg and orally at a dose of 2.5 mg /kg. Residue studies were carried out with supplemented feed at the rate of 100 mg /kg of feed for monensin in turkeys and 70 mg /kg for salinomycin in chickens, respectively. Coccidiostats had a low bioavailability in poultry (around 30% for monensin in chickens, around 1% for monensin in turkeys and around 15% for salinomycin in chickens). Monensin in chickens had a longer terminal half‐life (between 3.07 and 5.55 h) than both monensin in turkeys (between 1.36 and 1.55 h) and salinomycin in chickens (between 1.33 and 1.79 h). The tissue /plasma partition coefficients showed a higher affinity of both monensin and salinomycin for fat, followed by liver and muscle tissue. The depletion data showed a fairly rapid elimination of coccidiostats in all the tissues after cessation of treatment. According to the results of depletion studies, a withdrawal period of 1 day seems sufficient to avoid undesirable exposure of consumers.     

The efficacy of anticoccidial products against Eimeria spp. in northern bobwhites

To determine whether chemotherapeutic compounds available for use in domestic poultry are effective at controlling coccidiosis in northern bobwhites (Colinus virginianus), we tested 13 chemotherapeutic anticoccidials including amprolium (250 parts per million [ppm]), clopidol (125 ppm), diclazuril (1 ppm and 2 ppm), decoquinate (30 ppm), lasalocid (120 ppm), monensin (90 ppm), narasin/nicarbazin (36/36 ppm), robenidine (33 ppm), roxarsone (50 ppm), sulfadimethoxine/ ormetoprin (125/75 ppm), salinomycin (60 ppm), semduramicin (25 ppm), and zoalene (125 ppm and 150 ppm). Three tests were conducted using two replicates of 10 birds each: Infected, unmedicated controls and medicated birds were challenged with 1 x 10(6) oocysts of a field isolate consisting primarily of Eimeria lettyae. Subsequently, we tested clopidol, lasalocid, salinomycin, diclazuril (1 ppm), and monensin against mixed-species field isolates containing E. lettyae, E. dispersa, E. colini, or all. Weight gain, gross intestinal lesions, severity of diarrhea, and feed conversion ratio (FCR) 6 days postinfection were recorded. Lesion score, as previously reported, was unreliable as a measure of severity of infection in comparison with weight gain, fecal scores, and FCR. Excellent to good efficacy was found in clopidol, decoquinate, diclazuril (1 ppm and 2 ppm), and in lasalocid, narasin and nicarbazin, robenidine, sulfadimethoxine/ormetoprin, and zoalene (150 ppm). Marginal protection was found using monensin, salinomycin, semduramicin, or a roxarsone/semduramicin combination. Amprolium, roxarsone, and zoalene (125 ppm) were ineffective at controlling coccidia. Two of the six isolates tested against diclazuril 1 ppm and clopidol demonstrated a high degree of resistance, but none of the six isolates was resistant to lasalocid. Four of the eight isolates showed mild to moderate, and moderate to high, resistance against monensin and salinomycin, respectively. These findings indicate that several available compounds are effective at controlling coccidiosis in bobwhites.     

The synergistic activity of tiamulin and chlortetracycline: in-feed treatment of bacterially complicated enzootic pneumonia in fattening pigs

The antibacterial effects of a combination of tiamulin and chlortetracycline in vitro against a number of field isolates of Pasteurella multocida, Haemophilus pleuropneumoniae and Bordetella bronchiseptica were examined. There was a marked synergism between the two antibiotics against all eight isolates of P multocida, against seven of nine isolates of H pleuropneumoniae and against the single strain of B bronchiseptica tested. Two field trials were carried out on a herd with a history of complicated enzootic pneumonia where the presence of Mycoplasma hyopneumoniae and P multocida had been established and subsequently the presence of H pleuropneumoniae was discovered. Feed containing tiamulin at 100 ppm combined with chlortetracycline at 300 ppm was given for seven days to pigs affected with pneumonia, and the results were compared with untreated controls and pigs receiving chlortetracycline at 300 ppm. There was a follow-up observation period of three weeks when all groups received unmedicated feed. During the medication period the combination treated groups showed a statistically significant increase in average daily weight gain of 156 g (20.4 per cent) and in feed conversion efficiency of 0.576 (20.8 per cent) and a numerical improvement in average disease score in comparison with the untreated controls. These improvements were approximately double those observed in the groups treated with 300 ppm chlortetracycline which showed improvements of 93 g (12.2 per cent) in average daily gain and 0.301 (10.9 per cent) in feed conversion efficiency. During the following three weeks most of the initial gains were lost, probably owing to the reinfection of the treated groups by the untreated controls.     

The efficacy of salinomycin as a growth promotant for swine from 9 to 97 kg

Six trials involving 586 pigs initially averaging 9 kg were conducted at three locations (two trials/location) to evaluate the effects of the dietary addition of 0, 27.5, 55, 82.5 and 110 ppm of a monocarboxylic polyether antibiotic, salinomycin, on feed intake, growth rate and feed efficiency of swine fed corn-soybean meal-based diets. Over the total trial (9 to 97 kg), quadratic improvements in gain (P less than .01) and feed:gain (P less than .04) occurred with increasing level of salinomycin, but feed intake was not affected (P greater than .25). Mean improvements for all drug levels over control values for the total trial were 4.3% for daily gain (P less than .01) and 3.4% for feed:gain (P less than .01). For the total trial, rate and efficiency of gain were optimized in pigs fed the 82.5-ppm level of salinomycin with an improvement of 5.2% in daily gain and 4.8% in feed:gain over pigs fed the control diet. The absence of any significant trial X treatment interaction suggests that the nature of the response was not dependent on differences in environment, management or other factors that existed among trial locations.     

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.     

Tiamulin resistance in porcine Brachyspira pilosicoli isolates

There are few studies on antimicrobial susceptibility of Brachyspira pilosicoli, therefore this study was performed to investigate the situation among isolates from pigs. The tiamulin and tylosin susceptibility was determined by broth dilution for 93 and 86 porcine B. pilosicoli isolates, respectively. The isolates came from clinical samples taken in Swedish pig herds during the years 2002 and 2003. The tylosin minimal inhibitory concentration (MIC) was >16 microg/ml for 50% (n=43) of the isolates tested. A tiamulin MIC >2 microg/ml was obtained for 14% (n=13) of the isolates and these were also tested against doxycycline, salinomycin, valnemulin, lincomycin and aivlosin. For these isolates the susceptibility to salinomycin and doxycycline was high but the MICs for aivlosin varied. The relationship between the 13 tiamulin resistant isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Among the 13 isolates 10 different PFGE patterns were identified.     

The effect of salinomycin on health status and performance of sows and their litters: a dose titration study

Two hundred and fifty gilts and sows (Dalland parent stock) were divided randomly and allocated into the following five experimental groups: SAL0 = negative controls, SAL20 = 20 mg salinomycin per kg of feed, SAL40 = 40 mg salinomycin per kg of feed, SAL60 = 60 mg salinomycin per kg of feed and SAL80 = 80 mg salinomycin per kg of feed. Each gilt and sow was allocated to one of the five groups after the confirmation of the pregnancy using the ultrasonic method and remained under treatment for two consecutive breeding cycles. Throughout the experimental period several parameters related to sow health status, performance and fertility, as well as to health status and performance of their litters were recorded and calculated. Results indicated that salinomycin improves most of the parameters examined, as it leads to significantly higher (P < 0.05): (i) sow body weight gain during gestation; (ii) number of piglets born alive and weaned; (iii) piglet body weight at birth and at weaning, as well as to significantly lower (P < 0.05): (i) prevalence of thin sow syndrome at weaning; (ii) sow body weight loss during lactation; (iii) weaning-to-oestrus interval; (iv) piglet diarrhoea score during lactation; and (v) preweaning mortality. The best results were obtained at the inclusion levels of 40 and 60 mg salinomycin per kg of feed.     

Safety of lasalocid in turkeys and its compatibility with tiamulin

An investigation involving 640 turkeys demonstrated that the inclusion of lasalocid continuously from day-old to 16 weeks of age, at levels up to 375 ppm in the feed, produced no adverse effects; furthermore, the inclusion of 125 ppm lasalocid in the feed was compatible with the administration of 250 ppm tiamulin in the drinking water continuously for five days to turkeys over the same age range.     

Supplementing salinomycin to diets for growing-finishing pigs

Feeding experiments with growing-finishing pigs were carried out to study the effect of different dietary salinomycin concentrations upon animal performance. Besides a dietary treatment without antibiotic, three treatments consisted of 20/10 mg/kg, 40/20 mg/kg and 60/30 mg/kg salinomycin (the first and second number refer to the salinomycin content in grower and finisher diet, respectively). Compared to the control group, feeding diets with 20 or 40 mg/kg salinomycin resulted in significantly higher weight gain in the grower period (25-45 kg body weight), while also feed conversion was lower (although not statistically significant). In the finisher period (45-100 kg body weight) salinomycin had no significant effect upon weight gain or feed conversion efficiency, but the 20 and 30 mg/kg treatments yielded the best results. Considering the grower and finisher period together the dietary treatments 40/20 mg/kg and 60/30 mg/kg showed highest growth rate and most favourable feed conversion, although not statistically significant. Carcass characteristics (dressing percentage, carcass length, backfat thickness, percent meat) were not affected by dietary salinomycin supplementation.     

The effect of salinomycin on apparent digestibility, indices of rumen fermentation and fattening and slaughter yields of cattle

The influence of salinomycin (0, 15, 30 and 60 mg per animal and day) on apparent digestibility of artificially dried grass was investigated in four experiments with five wether each. Three long term individual feeding experiments (210 to 252 days) with 72 growing bulls were carried out. The influence of various salinomycin levels (100 to 300 mg per animal and day) were investigated on parameters of rumen fermentation as well as fattening and slaughtering results. Salinomycin decreased insignificantly (P greater than 0.05) the apparent digestibility of organic matter (71.0; 70.1; 68.7 and 68.4%) and crude carbohydrates (71.8; 70.3; 69.2 and 68.5% resp.). The digestibility of other nutrients was not influenced. Supplementation of salinomycin reduced molar concentration of acetate (49 to 115) and butyrate (22 to 82) and increased propionate (110 to 199 mmoles per mol) in rumen liquid. Dry matter intake of bulls declined (0.8%, 13.5 and 24.6; 4.7% of experiments 1 to 3) when salinomycin was added. Daily weight gain (6.5 and 1.0%) and feed efficiency (6.8 and 6.3%) of bulls supplemented with salinomycin were improved in experiments 1 and 3. Significant decrease of feed intake of bulls of experiment 2 affected decline of weight gain probably as consequence of high salinomycin levels. Slaughtering results (except experiment 2) and body composition of bulls were not significantly influenced by salinomycin. Under consideration of own results and some references 10 to 20 mg per kg dry matter or 50 to 150 mg salinomycin per fattening bull and day are recommended as optimal level.     

Efficacy of maduramicin against ionophore-tolerant field isolates of coccidia in broilers

Maduramicin ammonium was given at 2.5-8 ppm in the feed to broilers experimentally infected with coccidia recently isolated from broiler farms where ionophores had been used for several years. Infection pressure varied from mild to severe in five trials: mortality in unmedicated controls ranged from 0 to 59%, intestinal lesion scores were high, and weight gain was depressed by the infections. The cultures of Eimeria were partly resistant to ionophores: birds medicated with monensin at 100-121 ppm had only modest reductions in lesion scores and incomplete protection against weight loss or mortality. Control of infections by maduramicin was significant at 4 ppm but best at 5-7 ppm. Maduramicin was more effective than monensin or narasin, but about the same as salinomycin, in reducing lesions and mortality and in protecting performance. Maduramicin was well tolerated within the dose range of 5-7 ppm.     

Experimental infections with Actinobacillus pleuropneumoniae in pigs--I. Comparison of five different parenteral antibiotic treatments.

SPF pigs aged 10 weeks were infected intranasally with Actinobacillus pleuropneumoniae serotype 2. After the onset of clinical symptoms of respiratory disease, which occurred 20 h post-infection, parenteral treatment with ceftiofur, danofloxacin, enrofloxacin, penicillin or tiamulin was initiated (n = 8 per group). Untreated groups, of which one was infected, served as controls. The uninfected control group did not show any signs of disease, while the infected control group was severely affected by the infection and also expressed a decreased weight gain following the challenge. Based on clinical signs, the magnitude of pathological lesions in the respiratory tract found at necropsy performed 17 days post-infection and the number of reisolates of A. pleuropneumoniae made at necropsy, treatments with the quinolones (danofloxacin and enrofloxacin) and the cephalosporine (ceftiofur) were superior to those with penicillin and tiamulin. The latter groups also developed antibodies to A. pleuropneumoniae to a larger extent. Some of the pigs treated with ceftiofur and danofloxacin developed antibodies to A. pleuropneumoniae, and the microbe was reisolated from approximately 50% of these animals. In contrast, pigs treated with enrofloxacin did not develop antibodies to A. pleuropneumoniae, and the challenge strain was not found at necropsy. The performance with respect to daily weight gain and feed conversion corresponded well with the clinical signs developed and the findings made at necropsy. The decreased growth recorded during the acute phase of the disease was, to a large extent, caused by a reduced feed intake.     

Anticoccidial efficacy of diclazuril in broilers under simulated natural conditions in floor pens

Anticoccidial efficacy of diclazuril given for 42 to 49 days of age was evaluated in broiler chickens. Mortality from coccidiosis in unmedicated controls averaged 12.90% for six experiments. Treatment with diclazuril at 0.5, 1.0, and 1.5 ppm reduced coccidiosis mortality to 1.41%, 0.85%, or 0.63%, respectively, and reduced average total lesion scores by 78%, 81% or 82%, respectively. The final live weight and feed conversion at 49 days of age was significantly improved by treatment with diclazuril at all levels. Comparisons in some trials suggested that 1.0 ppm of diclazuril was equal or superior to the other anticoccidial drugs. There was no evidence that diclazuril harmed performance, even when given at 1.5 ppm.