<i>Eimeria tenella</i>: experimental development of resistance to monensin in the chicken

Chapman, H. D.

doi:10.1017/s0031182000001086

Cited by 23 publications

(4 citation statements)

References 11 publications

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“…Chapman (1984b) propagated the drug-sensitive Houghton strain of E. tenella in groups of 30 birds each infected with 10 6 oocysts and medicated with 100 mg/ kg of monensin, and after 16 passages, a partially resistant line was produced. Passage of this line in birds medicated with 200 or 300 mg/kg of monensin did not increase the degree of resistance despite the increase in drug selection pressure.…”

Section: Selection Of Resistancementioning

confidence: 99%

Forty years of monensin for the control of coccidiosis in poultry

Chapman

Jeffers

Williams³

2010

Poultry Science

261

167

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In July 1971, the polyether ionophorous antibiotic monensin was introduced in the United States for the control of coccidiosis in poultry. At that time, prospects for new anticoccidial agents were not good. Amprolium had enjoyed several years of use, but many other compounds had been abandoned as resistance to them developed. After the introduction of monensin, most commercial broilers were medicated with the drug and it is still widely used for this purpose today. Apart from in poultry, monensin is also used to control coccidiosis in game birds, sheep, and cattle. Indeed, more animals have been medicated with ionophores, such as monensin, for control of disease than any other medicinal agents in the history of veterinary medicine. In this review, we discuss the discovery, mode of action, and efficacy of monensin, together with matters of importance to the poultry industry such as commercial use, drug resistance, toxicity, pharmacology and residues, host immunity to coccidiosis, and effects in other avian species.

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Section: Selection Of Resistancementioning

confidence: 99%

Forty years of monensin for the control of coccidiosis in poultry

Chapman

Jeffers

Williams³

2010

Poultry Science

261

167

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“…This is a clear indicator of the difficulty encountered by researchers in developing resistance to MON in laboratory environments (Chapman, 1976;Weppelman et al, 1977). Although Chapman (1984b) was ultimately able to produce a strain that was partially resistant to MON, he found the trait unstable after 5 generations in the absence of the drug. These observations correlate well with field experiences, since the first reports of ionophore resistance in the field occurred approximately 10 yr after the drug was introduced to the industry (Jeffers, 1981;McDougald, 1981;Chapman, 1982b).…”

Section: Discussionmentioning

confidence: 95%

Selection for Resistance to Monensin, Nicarbazin, and the Monensin Plus Nicarbazin Combination

Bafundo

Jeffers

1990

Poultry Science

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Two series of experiments were conducted to assess the relative ability of strains of Eimeria acervulina and Eimeria tenella to develop resistance to monensin (MON), nicarbazin (NIC), and the monensin plus nicarbazin combination (MON plus NIC). The studies were designed so that drug concentrations in the selection experiments were increased whenever possible. During selection, E. acervulina increased its reproductive index in the presence of NIC or MON plus NIC, equivalent selection in the presence of MON resulted in only a slight increase in reproductive ability. Eimeria tenella, however, was unable to increase its reproductive capacity to the respective drugs. Sensitivity tests after 60 generations of selection revealed that patterns of resistance development for E. acervulina and E. tenella corresponded with the changes in reproductive indices established in the selection experiments. Thus, results of these tests indicate that E. acervulina possesses the ability to develop resistance to NIC and MON plus NIC. Under essentially the same conditions of selection, E. tenella developed only partial resistance to the respective drugs.

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“…A reduced sensitivity of Eimeria to some anticoccidials such as ionophores has been suspected for years (Chapman, 1982;Li et al, 2004;Stephan et al, 1997). The commercial success of ionophores indicates that the challenge conditions in the field are compatible with their different efficacy profiles (Bafundo and Jeffers, 1990;Chapman, 1984;Jeffers, 1978).…”

Section: Discussionmentioning

confidence: 99%

Efficacy and Characteristics of different Methods of Coccidiosis Infection in Broiler Chickens

Elmusharaf¹

2010

American Journal of Animal and Veterinary Sciences

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Problem statement: Different methods of experimental infection of broiler chickens withEimeria species have been described in the literature. These methods had not been compared and contrasted so as to contribute to the selection of the most appropriate model of coccidiosis in broiler chickens. Identifying such a model was important to speed up the screening of potential coccidiostatics. Approach: In five different experiments with broiler chickens, we used different methods of infection with Eimeria species. In this paper the different methods and the results have been evaluated. Results: Administration through gavage into the crop of relatively low doses of either Eimeria tenella alone, or in combination with Eimeria acervulina and Eimeria maxima, did not influence body-weight gain and feed intake, but did induce intestinal lesions and faecal shedding of oocysts. The administration of an identically high number of sporulated oocysts in the form of a mixture of the three Eimeria species, either through a single dose by gavage or through the litter, produced similar lowering effects on body-weight gain or feed intake, similar degrees of severity of intestinal lesions and similar rates of faecal oocyst shedding. Conclusion: Depending on the variables considered of interest, the present data may indicate the most appropriate model. The model using infection with oocysts through the litter may optimally mimic the field situation in combination with controlled conditions and allowing experimental flexibility and a high number of experimental units within the research facility.

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Eimeria tenella: experimental development of resistance to monensin in the chicken

Cited by 23 publications

References 11 publications

Forty years of monensin for the control of coccidiosis in poultry

Forty years of monensin for the control of coccidiosis in poultry

Selection for Resistance to Monensin, Nicarbazin, and the Monensin Plus Nicarbazin Combination

Efficacy and Characteristics of different Methods of Coccidiosis Infection in Broiler Chickens

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