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1.
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. 相似文献
2.
《Veterinary microbiology》1997,54(2):195-200
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. 相似文献
3.
An experiment was carried out to study the effects of vaccination with Paracox, a live, attenuated vaccine against avian coccidiosis, on broilers isolated from extraneous Eimeria parasites. The study involved 3200 broiler chickens raised in floor pens similar to commercial conditions, but in an initially Eimeria-free environment. Forty percent of the chickens were vaccinated at 3 days of age and given either a basal unmedicated feed or a feed supplemented with the feed antibiotic virginiamycin. Unvaccinated birds were given either the basal feed or feed supplemented either with virginiamycin or the anticoccidial ionophore narasin. At slaughter at 36 days of age vaccinated birds had a lower live weight than non-vaccinated birds. The difference was 4.6% in unmedicated, and 6.0% in virginiamycin medicated chickens. Feed conversion ratio at slaughter was 2.5% higher for unmedicated vaccinated birds, and 1.3% higher for virginiamycin medicated vaccinated birds, compared to respective non-vaccinated groups. There was no significant difference in overall performance of unvaccinated birds given narasin as compared to virginiamycin. At 10 days post vaccination vaccinated birds had a higher number of Clostridium perfringens in the caeca, but there was no difference thereafter. Throughout the experiment, caecal clostridial counts were considerably higher in vaccinated unmedicated birds than in unvaccinated birds given narasin. The number of oocysts shed in the vaccinated groups was very low, but during a subsequent challenge with E. maxima and E. tenella the birds' immunity was found to be satisfactory. 相似文献
4.
The efficacy of narasin in the control of necrotic enteritis (NE) was investigated in a floor pen study of 2000 broiler chickens using a Clostridium perfringens feed inoculum challenge model. Treatments were 1) nonmedicated, nonchallenged; 2) nonmedicated, challenged; 3) narasin, nonchallenged; 4) narasin, challenged. Narasin was administered at 70 ppm in the feed from day 0 to trial termination on day 41. Challenge inoculum contained approximately 1 x 10(8) colony-forming units CP/ml and was administered from day 14 to day 16. In the unmedicated groups, challenged birds had significantly (P < 0.05) lower mean body weight and reduced feed efficiency at day 21 and significantly (P < 0.01) higher cumulative NE mortality at day 41 compared with unchallenged. Similarly, among unmedicated birds, those challenged had a significantly (P < 0.01) higher mean NE score on day 17 and significantly (P < 0.05) higher mean huddling scores on days 15-17 than unchallenged. Among challenged birds, those fed narasin had significantly (P < 0.05) higher mean body weight and improved feed efficiency at days 21 and 41 and significantly (P < 0.01) lower cumulative NE mortality at day 41 than unmedicated. Similarly, among challenged birds, those receiving narasin had a lower mean NE score on day 17 (P > 0.05) and significantly (P < 0.05) lower huddling scores on days 16 and 17 than unmedicated. Coccidiosis lesion scores were zero for birds euthanatized from all treatment groups on day 17, suggesting that the beneficial effects of narasin were not due to prevention of coccidiosis. This study thus provides evidence that narasin is effective in the prevention of necrotic enteritis in broiler chickens. 相似文献
5.
Anticoccidial evaluation of halofuginone, lasalocid, maduramicin, monensin and salinomycin 总被引：4，自引：0，他引：4
The activities of five anticoccidials were compared against Eimeria species in/of chickens, in controlled in vivo and in vitro laboratory studies. Two more recent and potent market entries (maduramicin and halofuginone) were compared with three older polyether antibiotic anticoccidials (monensin, lasalocid and salinomycin). Halofuginone, lasalocid, maduramicin, monensin and salinomycin were evaluated at 3, 125, 5, 120 and 66 ppm, respectively, of active drug in the diets. At these levels, all five drugs demonstrated significant activity against Eimeria tenella, E. maxima, E. necatrix, E. brunetti and E. acervulina (in vivo). Monensin was least effective against E. tenella, and one of the lesser efficacious drugs against E. necatrix, maduramicin, was least effective against E. maxima. In studies of single Eimeria species infections, comparable weight gains were noted for the drugs. In the mixed Eimeria species infections, however, birds treated with maduramicin had significantly higher weight gains than did birds medicated with monensin. Unlike in vivo potencies, titration in vitro indicated that monensin was most potent (active at 10(-6) mcg ml-1), and maduramicin and lasalocid least potent (inactive at less than or equal to 10(-3) mcg ml-1). 相似文献
6.
Collier CT Hofacre CL Payne AM Anderson DB Kaiser P Mackie RI Gaskins HR 《Veterinary immunology and immunopathology》2008,122(1-2):104-115
This study tested the hypothesis that a host mucogenic response to an intestinal coccidial infection promotes the onset of necrotic enteritis (NE). A chick NE model was used in which birds were inoculated with Eimeria acervulina and E. maxima and subsequently with Clostridium perfringens (EAM/CP). A second group of EAM/CP-infected birds was treated with the ionophore narasin (NAR/EAM/CP). These groups were compared to birds that were either non-infected (NIF), or infected only with E. acervulina and E. maxima (EAM), or C. perfringens (CP). The impact of intestinal coccidial infection and anti-coccidial treatment on host immune responses and microbial community structure were evaluated with histochemical-, cultivation- and molecular-based techniques. Barrier function was compromised in EAM/CP-infected birds as indicated by elevated CFUs for anaerobic bacteria and C. perfringens in the spleen when compared to NIF controls at day 20, with a subsequent increase in intestinal NE lesions and mortality at day 22. These results correlate positively with a host inflammatory response as evidenced by increased ileal interleukin (IL)-4, IL-10 and IFN-gamma RNA expression. Concurrent increases in chicken intestinal mucin RNA expression, and goblet cell number and theca size indicate that EAM/CP induced an intestinal mucogenic response. Correspondingly, the growth of mucolytic bacteria and C. perfringens as well as alpha toxin production was greatest in EAM/CP-infected birds. The ionophore narasin, which directly eliminates coccidia, reduced goblet cell theca size, IL-10 and IFN-gamma expression, the growth of mucolytic bacteria including C. perfringens, coccidial and NE lesions and mortality in birds that were co-infected with coccidia and C. perfringens. Collectively the data support the hypothesis that coccidial infection induces a host mucogenic response providing a growth advantage to C. perfringens, the causative agent of NE. 相似文献
7.
Donor chickens given feed medicated with one or two levels of decoquinate or given non-medicated feed were infected with oocysts of Eimeria tenella or E. maxima per os. Twelve hours after inoculation with oocysts liver, mid-intestine or ceca homogenates were fed to previously uninfected recipient chickens. The results showed that continuous medication with decoquinate was effective in preventing the transfer of sporozoites from the intestine to the liver. Oocysts were detected in the feces of all recipients of tissue from non-medicated donors, showing that some sporozoites of E. maxima and E. tenella are normally transferred to liver. Young broiler chickens were immunized by oral inoculation of E. maxima oocysts. The immune status of similar chickens inoculated with sporozoites of the same species directly into the liver or spleen were assessed. During the experimental period half of the chicks were provided with non-medicated food and the remainder were given feed supplemented with decoquinate; decoquinate was effective in arresting the development of the sporozoites. Two weeks after initial infection the birds were challenged with oocysts of E. maxima per os. Injection of sporozoites into the spleen did not protect against challenge. Birds inoculated with sporozoites into the liver were unable to develop a significant level of immunity. When the drug pressure was removed from these birds, parasitism of the intestine occurred and immunity developed. 相似文献
8.
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. 相似文献
9.
K. Elwinger C. Schneitz E. Berndtson O. Fossum B. Teglf B. Engstm 《Acta veterinaria Scandinavica》1992,33(4):369-378
Two trials were conducted to study the effects of a competitive exclusion (CE) product BROILACT and the anticoccidial narasin on the incidence of necrotic enteritis (NE), the numbers of Clostridium perfringens (CP) in the caeca of broiler chicks and the performance of the birds. In trial 1 the effects of type of protein and partial replacement of a narasin containing diet with whole wheat were also studied. All groups of chicks were studied up to the point of slaughter at 43 days of age and after evisceration in a processing plant to determine slaughter yield. In trial 1, statistically significant results included the following: CE-treatment reduced total mortality, and incidence of NE, on diet containing animal but not vegetable protein. Caecal carriage of CP was also reduced, while slaughter yield increased. Narasin reduced caecal carriage of CP and increased both growth rate and slaughter yield in both trials. Whole wheat replacement improved feed conversion but reduced bird growth rate. In trial 2, both CE-treatment and narasin influenced feed intake, CE-treatment significantly only at days 22 and 44. Narasin improved feed conversion until 5 weeks of age and CE-treatment did so until 22 days of age. In both trials, there was also an interaction effect indicating that CE-treatment increased slaughter yield for birds that were not fed narasin. 相似文献
10.
Field observations suggest that coccidiosis is a common cause of death in broiler chicken flocks fed diets containing sufficient amounts of ionophore antibiotics (monensin, narasin, etc.) and contaminated with mycotoxins, particularly with T-2 fusariotoxin. To study this phenomenon, broiler chickens fed diets containing different amounts of T-2 toxin and free from monensin, or containing a preventive dose (100 mg/kg of feed) of monensin, were infected experimentally with coccidian oocysts. In all groups fed a diet containing monensin plus T-2 toxin severe clinical symptoms of coccidiosis (blood-stained faeces etc). occurred. Deaths and retarded growth depended on the toxin dose and were considerable. The body mass gain of chicks fed a diet containing monensin and T-2 toxin but not infected with coccidia was inferior to that of groups fed diets which contained either monensin or T-2 toxin (experiment 2). On the basis of these findings a negative interaction of the two compounds is assumed. This seems to be supported by the results of experiment 3, i. e. the finding that the lethal dose of narasin, a compound closely related to monensin both in chemical structure and mechanism of action, proved to be much lower (LD50 = 102 mg/kg body mass) for chickens fed a diet supplemented with T-2 toxin than for the control chickens (LD50 = 176 mg/kg body mass). The present results suggest that the feeding of diets severely contaminated with T-2 toxin may alter the anticoccidial efficacy of monensin. 相似文献
11.
Clostridium perfringens type A, Eimeria acervulina, and Eimeria necatrix were used to produce necrotic enteritis in chickens. The disease was produced in all groups of birds that received feed contaminated with C. perfringens. Mortality due to necrotic enteritis was highest (53%) in birds infected with E. acervulina before infection with clostridia. There was a significant difference in mortality rates between birds infected with E. acervulina and birds infected with E. necatrix before infection with C. perfringens. Mortality rates also differed significantly between the group infected with E. necatrix and the group that received only feed contaminated with C. perfringens. It was concluded that under field conditions, coccidia can play a significant role in the occurrence of necrotic enteritis when a sufficient number of toxigenic strain of C. perfringens type A is present. The pathological changes induced by clostridia and coccidia are described. 相似文献
12.
本试验将560只Ross 308肉鸡随机分为7组,每组8个重复,每个重复10只鸡。各组日粮处理如下:对照组饲喂基础日粮,未感染产气梭菌,T1组感染产气梭菌,T2组感染产气梭菌+0.2 g/kg阿维霉素,T3组感染产气梭菌+0.40 g/kg百里香酚,T4组感染产气梭菌+0.2 g/kg血根碱,T5组感染产气梭菌+0.5 g/kg香芹酚、肉桂醛和辣椒素混合物,T6组感染产气梭菌+0.2 g/kg百里香酚和茴香混合物。结果显示:T2组第3周料重比显著高于对照组(P<0.05)。T1组屠宰率显著下降(P<0.05),小肠重量显著增加(P<0.05)。第4周时,T6组血液总蛋白和球蛋白含量显著升高(P<0.05),T5组肝脏谷丙转氨酶活力显著升高(P<0.05)。T5和T6组硫代巴比妥酸反应物含量均显著升高(P<0.05)。同样,T5和T6组绒毛高度和隐窝深度也显著增加(P<0.05)。综上所述,与抗生素相比,肉鸡日粮添加中草药制剂在维持产气荚膜梭菌感染肉鸡生长性能和血液生化特性方面具有应用的优势。 相似文献
13.
A survey of sensitivity to anticoccidial drugs in 60 isolates of coccidia from broiler chickens in Brazil and Argentina 总被引：3，自引：0，他引：3
Coccidia were isolated from 90 broiler farms in 15 poultry-producing areas in Brazil and Argentina. Sixty isolates were tested for sensitivity to 7 anticoccidial drugs. The common species were: a) Eimeria tenella, 47 isolates; b) E. maxima, 49 isolates; c) E. acervulina, 44 isolates; d) E. mitis, 26 isolates; and e) E. brunetti, 12 isolates. Isolates were considered sensitive to drugs if intestinal lesion scores of medicated broilers were reduced by at least 50% compared with unmedicated infected broilers or if weight gain was at least 75% of that of uninfected birds in a 6-day laboratory test. According to lesion scores, there was evidence of resistance or seriously reduced sensitivity to monensin in 20 isolates, narasin in 29, salinomycin in 11, maduramicin in 1, clopidol in 36, amprolium in 40, and nicarbazin in 1. According to broiler weight gain, there was resistance to monensin in 36 isolates, narasin in 32, salinomycin in 28, maduramicin in 2, clopidol in 28, amprolium in 50, and nicarbazin in 4. These results suggested incomplete cross resistance of coccidia to polyether ionophorous drugs. The degree of resistance might be explained by previous patterns of use of these drugs. 相似文献
14.
H D Chapman 《Research in veterinary science》1989,46(3):419-420
Treatment with toltrazuril, sulphaquinoxaline/pyrimethamine and amprolium/ethopabate prevented mortality in chickens infected with field isolates of Eimeria tenella. Amprolium/ethopabate was the most effective drug in reducing lesions caused by the parasites. Few oocysts of E tenella were produced in birds medicated with sulphaquinoxaline/pyrimethamine or amprolium/ethopabate and none in those medicated with toltrazuril. 相似文献
15.
The dosing of young chicks with cultures of normal gut flora has been termed "competitive exclusion" (CE). This study was undertaken to examine, under field conditions, the effect of CE treatment on counts of intestinal Clostridium perfringens (CP) and on the occurrence of CP-associated disease in broiler chickens. A farm having recurrent CP-associated health problems was selected as study site. The study comprised four broiler houses, with one treated and one untreated flock per house. Treated birds were sprayed with the CE product Broilact upon arrival at the farm. All flocks were offered feed containing the ionophorous anticoccidial agent narasin. The feed did not contain growth promoters. Treatment was associated with positive but statistically nonsignificant effects on gut health. Delayed intestinal proliferation of CP and delayed appearance of CP-associated gut lesions were found in CE-treated flocks. This delay was associated with improved production performance at slaughter. 相似文献
16.
1. This study investigated the effect of Eimeria spp./Clostridium perfringens induced necrotic enteritis and traditional antibiotic preventatives on intestinal micro-architecture and mucin profile. 2. A total of 600 Cobb 500 broiler chickens were randomly assigned to the following three groups: (i) unchallenged, (ii) challenged, and (iii) zinc bacitracin/monensin (ZnB/monensin) (n = 25 chickens/pen, 8 pens/group). The challenged and ZnB/monensin chickens were individually inoculated with Eimeria acervulina, E. maxima and E. tenella and C. perfringens type A (EHE-NE18) at 9 and 15 d post-hatch respectively, to induce necrotic enteritis. 3. The challenge procedure significantly decreased villus height, increased villus width and increased crypt depth in the challenged compared to the unchallenged chickens. Zinc bacitracin and monensin maintained villus-crypt structure similar to that of the unchallenged chickens. 4. Mucin profile was not affected by Eimeria spp./C. perfringens challenge as demonstrated by periodic acid-Schiff and high iron diamine-alcian blue pH 2 x 5 staining. Zinc bacitracin and monensin decreased the number of intestinal mucin-containing goblet cells. 5. Lectin histochemistry showed a trend towards greater Arachis hypogea (PNA) reactivity in unchallenged chickens. 6. In summary, Eimeria spp./C. perfringens challenge disrupted intestinal micro-architecture; however, challenge did not appear to affect intestinal mucin profile. Traditional antibiotics, zinc bacitracin and monensin maintained micro-architecture. 相似文献
17.
This study was undertaken to determine the in vitro susceptibility of Clostridium perfringens, isolated from poultry to antimicrobials used in poultry production. The minimal inhibitory concentration (MIC) of eight antimicrobials, including the ionophoric coccidiostat narasin, was determined for 102 C. perfringens isolates, 58 from Sweden, 24 from Norway and 20 from Denmark. Susceptibility to each antimicrobial compound was determined by broth microdilution. The isolates were obtained from broilers (89), laying hens (9) and turkeys (4), affected by necrotic enteritis (NE) or by C. perfringens associated hepatitis (CPH), and from healthy broilers. All strains, regardless of origin, proved inherently susceptible to ampicillin, narasin, avilamycin, erythromycin and vancomycin. A low frequency of resistance to virginiamycin and bacitracin was also found. Resistance to tetracycline was found in strains isolated in all three countries; Sweden (76%), Denmark (10%) and Norway (29%). In 80% of the tetracycline-resistant isolates, the two resistance genes tetA(P) and tetB(P) were amplified by PCR whereas in 20% only the tetA(P) gene was detected. No tetM gene amplicon was obtained from any of the tetracycline-resistant isolates. The uniform susceptibility to narasin revealed in this study shows that the substance can still be used to control clostridiosis. In this study, C. perfringens also showed a low degree of resistance to most other antimicrobials tested. Despite the small amounts of tetracycline used in poultry, a considerable degree of resistance to tetracycline was found in C. perfringens isolates from Swedish broilers. 相似文献
18.
Out of six isolates of coccidia of the species Eimeria tenella, obtained in the years 1984 and 1985 on farms with a stationary occurrence of coccidiosis, five were found to have reduced sensitivity or resistance to monensin. Neither were these isolates sensitive to further monovalent ionophorous anticoccidials narasin and salinomycin. The bivalent ionophorous anticoccidial lasalocid controlled five isolates completely, but for one its effectiveness was reduced. An isolate obtained on a farm with long-term absence of coccidiosis was sensitive to all anticoccidial drugs. 相似文献
19.
Responses of chickens vaccinated with a live attenuated multi-valent ionophore-tolerant Eimeria vaccine 总被引：3，自引：0，他引：3
Coccidiosis, caused by Eimeria species, is a serious economic disease of chickens (Gallus gallus) and the search for vaccines to control the disease is intensifying especially with the increasing threat of drug resistance. A live attenuated multi-valent ionophore-tolerant Eimeria vaccine has been developed that contains three ionophore-resistant Eimeria species, E. tenella, E. maxima and E. acervulina. The attenuated lines were derived from virulent field strains resistant to monensin ionophore by selection for early development in chicks. The vaccine was administered by gavage and through drinking water to broiler chickens, Chinese Yellow strain, reared in wire cages. Vaccinated medicated birds performed better than vaccinated unmedicated and medicated unvaccinated groups. The final mean weights of vaccinated medicated birds were significantly higher (P<0.05), and a better vaccine protection index, using both vaccinating methods, was achieved. Results indicated that concomitant use of ionophores and vaccines could be a useful adjunct to planned immunization in the control of coccidiosis. 相似文献
20.
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. 相似文献