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Rodriguez Lulimache, Ingrid Vanessa - One of the best experts on this subject based on the ideXlab platform.
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Uso de Anticoccidial natural a base de saponinas procedentes de Yucca schidigera y Trigonella foenum- graecum sobre la incidencia de coccidias y respuesta bioeconómica en pollos de engorde
Universidad Privada Antenor Orrego - UPAO, 2017Co-Authors: Rodriguez Lulimache, Ingrid VanessaAbstract:El objetivo de la investigación fue evaluar los efectos de un Anticoccidial natural a base de saponinas procedentes de Yucca schidigera y Trigonella foenum-graecum sobre la incidencia de coccidias y respuesta bioeconómica en pollos de engorde; para lo cual se utilizaron 75 pollos machos de la línea Cobb 500 de 1 a 42 días de edad, los cuales fueron distribuidos a través de un diseño completamente al azar, con tres tratamientos : DBSA (Dieta base sin adición de Anticoccidial), DBAN (Dieta base con adición de Anticoccidial natural), DBQI (Dieta base con adición de Anticoccidial químico - ionóforo), cinco repeticiones y cinco aves por unidad experimental. A los 14 días de edad los pollos recibieron 15 veces más de la dosis recomendada de la vacuna viva (Coccivac-D) conteniendo E. acervulina, E. maxima, E. mivati, E. tenella, E. necatrix, E. brunetti, E. hagani, E. praecox. Se evaluó el recuento de ooquistes de Eimeria en heces, calificación de lesiones intestinales, parámetros productivos (ganancia de peso, consumo de alimento, índice de conversión alimenticia, mortalidad) y análisis económico. Para el análisis estadístico se empleó ANOVA usando el programa estadístico Infostat y la prueba de Tukey para comparar diferencias entre tratamientos. Los resultados obtenidos indicaron que el Anticoccidial natural a base de saponinas procedentes de Yucca schidigera y Trigonella foenum-graecum controló la infección por coccidiosis disminuyendo el número de ooquistes en heces y las lesiones intestinales en pollos desafiados, presentando similar efecto que el tratamiento con adición de Anticoccidial químico – ionóforo; además ambos tratamientos no presentaron diferencia significativa en los parámetros productivos, por otro lado el uso de Anticoccidial natural como el uso de Anticoccidial químico – ionóforo obtuvieron la mejor rentabilidad.The objective of the research was to evaluate the effects of a natural Anticoccidial based on saponins from Yucca schidigera and Trigonella foenum-graecum on the incidence of coccidia and bioeconomic response in broilers; 75 male chickens from the Cobb 500 line, from 1 to 42 days old, were distributed through a completely randomized design with three treatments: DBSA (Base Diet without addition of Anticoccidial), DBAN ( Base diet with addition of natural Anticoccidial), DBQI (Base diet with addition of chemical Anticoccidial - ionophore), five replicates and five birds per experimental unit. At 14 days of age, chickens received 15 times the recommended dose of the live vaccine (Coccivac-D) containing E. acervulina, E. maxima, E. mivati, E. tenella, E. necatrix, E. brunetti, E. hagani, E. praecox. Eimeria oocysts were counted in feces, intestinal lesion score, productive parameters (weight gain, feed intake, feed conversion index, mortality) and economic analysis. For the statistical analysis, ANOVA was used using the statistical program Infostat and the Tukey test to compare differences between treatments. The results indicated that the natural anti-coccidial based on saponins from Yucca schidigera and Trigonella foenum-graecum controlled the coccidiosis infection, decreasing the number of oocysts in feces and intestinal lesions in challenged chickens, presenting a similar effect as the treatment with addition of Chemical Anticoccidial - ionophore; In addition both treatments did not present significant difference in the productive parameters, on the other hand the use of natural Anticoccidial as the use of Anticoccidial chemical - ionóforo obtained the best profitability.Tesi
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Uso de Anticoccidial natural a base de saponinas procedentes de yucca schidigera y trigonella foenum- graecum sobre la incidencia de coccidias y respuesta bioeconomica en pollos de engorde
Universidad Privada Antenor Orrego - UPAO, 2017Co-Authors: Rodriguez Lulimache, Ingrid VanessaAbstract:The objective of the research was to evaluate the effects of a natural Anticoccidial based on saponins from Yucca schidigera and Trigonella foenum-graecum on the incidence of coccidia and bioeconomic response in broilers; 75 male chickens from the Cobb 500 line, from 1 to 42 days old, were distributed through a completely randomized design with three treatments: DBSA (Base Diet without addition of Anticoccidial), DBAN ( Base diet with addition of natural Anticoccidial), DBQI (Base diet with addition of chemical Anticoccidial - ionophore), five replicates and five birds per experimental unit. At 14 days of age, chickens received 15 times the recommended dose of the live vaccine (Coccivac-D) containing E. acervulina, E. maxima, E. mivati, E. tenella, E. necatrix, E. brunetti, E. hagani, E. praecox. Eimeria oocysts were counted in feces, intestinal lesion score, productive parameters (weight gain, feed intake, feed conversion index, mortality) and economic analysis. For the statistical analysis, ANOVA was used using the statistical program Infostat and the Tukey test to compare differences between treatments. The results indicated that the natural anti-coccidial based on saponins from Yucca schidigera and Trigonella foenum-graecum controlled the coccidiosis infection, decreasing the number of oocysts in feces and intestinal lesions in challenged chickens, presenting a similar effect as the treatment with addition of Chemical Anticoccidial - ionophore; In addition both treatments did not present significant difference in the productive parameters, on the other hand the use of natural Anticoccidial as the use of Anticoccidial chemical - ionóforo obtained the best profitability.El objetivo de la investigación fue evaluar los efectos de un Anticoccidial natural a base de saponinas procedentes de Yucca schidigera y Trigonella foenum-graecum sobre la incidencia de coccidias y respuesta bioeconómica en pollos de engorde; para lo cual se utilizaron 75 pollos machos de la línea Cobb 500 de 1 a 42 días de edad, los cuales fueron distribuidos a través de un diseño completamente al azar, con tres tratamientos : DBSA (Dieta base sin adición de Anticoccidial), DBAN (Dieta base con adición de Anticoccidial natural), DBQI (Dieta base con adición de Anticoccidial químico - ionóforo), cinco repeticiones y cinco aves por unidad experimental. A los 14 días de edad los pollos recibieron 15 veces más de la dosis recomendada de la vacuna viva (Coccivac-D) conteniendo E. acervulina, E. maxima, E. mivati, E. tenella, E. necatrix, E. brunetti, E. hagani, E. praecox. Se evaluó el recuento de ooquistes de Eimeria en heces, calificación de lesiones intestinales, parámetros productivos (ganancia de peso, consumo de alimento, índice de conversión alimenticia, mortalidad) y análisis económico. Para el análisis estadístico se empleó ANOVA usando el programa estadístico Infostat y la prueba de Tukey para comparar diferencias entre tratamientos. Los resultados obtenidos indicaron que el Anticoccidial natural a base de saponinas procedentes de Yucca schidigera y Trigonella foenum-graecum controló la infección por coccidiosis disminuyendo el número de ooquistes en heces y las lesiones intestinales en pollos desafiados, presentando similar efecto que el tratamiento con adición de Anticoccidial químico – ionóforo; además ambos tratamientos no presentaron diferencia significativa en los parámetros productivos, por otro lado el uso de Anticoccidial natural como el uso de Anticoccidial químico – ionóforo obtuvieron la mejor rentabilidad
Lifang Zhang - One of the best experts on this subject based on the ideXlab platform.
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Anticoccidial activity of novel triazine compounds in broiler chickens
Veterinary parasitology, 2019Co-Authors: Min Zhang, Qiping Zhao, Rufeng She, Suhan Xia, Keyu Zhang, Lifang Zhang, Xiaoyang Wang, Mi Wang, Yingchun LiuAbstract:The objective of present studies was to evaluate and compare the Anticoccidial activity of triazine compounds in broiler chickens infected with E. tenella, E. necatrix, E. acervulina, E. maxima, and two field mixed Eimeria species. The Anticoccidial efficacy was evaluated using the Anticoccidial index (ACI). The results showed that Aminomizuril (AZL) and Ethanamizuril (EZL) were active metabolites of nitromezuril, which demonstrated excellent effectiveness against E. tenella, E. necatrix, E. acervulina, E. maxima, and the field Eimeria isolates in broiler chickens at a dosage of 10 mg/kg in feed. The Anticoccidial activities of AZL and EZL at dose 10 mg/kg were roughly equivalent to the parent nitromezuril at a dosage of 3 mg/kg in feed. The decrease in metabolite Anticoccidial activity is probably due to an increasing polarity of compounds in the metabolic processes. The sensitivity of two field Eimeria isolates to triazines EZL, diclazuril and toltrazuril was tested using 4 indices including Anticoccidial index (ACI), percent of optimum Anticoccidial activity (POAA), reduction of lesion scores (RLS) and relative oocysts production (ROP). Results showed that the sensitivity of EZL treatment against the two field Eimeria isolates were relatively superior to that of diclazuril and toltrazuril treatment. The field Eimeria isolates from Gansu Province was determined to be slightly, moderately and highly resistant to EZL, diclazuril and toltrazuril respectively. The field Eimeria isolates from Zhejiang Province was slightly, highly and slightly resistant to EZL, diclazuril and toltrazuril respectively. The results above indicated that the Anticoccidial activity of metabolites was lower than that of the parent nitromezuril and there was partial cross-resistance among triazines EZL, diclazuril and toltrazuril. However the field Eimeria isolates had higher sensitive to EZL than the triazines diclazuril and toltrazuril. It was suggested that the site of C4 substituents of phenol of triazine Anticoccidials may have important biological functions and the metabolite EZL would be a potential novel Anticoccidial agent worthy of more attention.
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Anticoccidial effects of a novel triazine nitromezuril in broiler chickens.
Veterinary parasitology, 2013Co-Authors: Chenzhong Fei, Qiping Zhao, Keyu Zhang, Xiaoyang Wang, Mi Wang, Chao Fan, Yang Lin, Wenli Zheng, Lifang ZhangAbstract:The Anticoccidial efficacy of 2-(3-methyl-4-(4-nitrophenoxy)phenyl)-1,2,4-triazine-3,5(2H,4H)-dione (nitromezuril, NZL), a novel triazine compound, was evaluated in three different studies under experimental conditions. The Anticoccidial efficacy was chiefly evaluated using the Anticoccidial index (ACI). The resistance level was determined by calculating ACI, percentage optimum Anticoccidial activity (POAA), reduction in lesion scores (RLS) and relative oocyst production (ROP). In the dose determination study (study A), NZL was added to the diet at doses of 1, 2, 3, 4, 5 and 6 mg/kg to test its efficacy against coccidiosis caused by Eimeria tenella. Groups treated with NZL 1mg/kg feed could observe the faecal dropping scores and caecal lesions. ACIs of NZL-treated groups reached 179-199. In the study on the Anticoccidial efficacy of 3mg/kg NZL in the diet (study B), only a few faecal oocysts and slight lesions were observed. NZL significantly promoted weight gain (WG) and reduced lesion scores (LS) compared to controls receiving diclazuril (DZL) (P
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Anticoccidial effects of a novel triazine nitromezuril in broiler chickens
Veterinary Parasitology, 2013Co-Authors: Chenzhong Fei, Qiping Zhao, Keyu Zhang, Xiaoyang Wang, Mi Wang, Chao Fan, Yang Lin, Wenli Zheng, Lifang ZhangAbstract:Abstract The Anticoccidial efficacy of 2-(3-methyl-4-(4-nitrophenoxy)phenyl)-1,2,4-triazine-3,5(2H,4H)-dione (nitromezuril, NZL), a novel triazine compound, was evaluated in three different studies under experimental conditions. The Anticoccidial efficacy was chiefly evaluated using the Anticoccidial index (ACI). The resistance level was determined by calculating ACI, percentage optimum Anticoccidial activity (POAA), reduction in lesion scores (RLS) and relative oocyst production (ROP). In the dose determination study (study A), NZL was added to the diet at doses of 1, 2, 3, 4, 5 and 6 mg/kg to test its efficacy against coccidiosis caused by Eimeria tenella . Groups treated with NZL 1 mg/kg feed could observe the faecal dropping scores and caecal lesions. ACIs of NZL-treated groups reached 179–199. In the study on the Anticoccidial efficacy of 3 mg/kg NZL in the diet (study B), only a few faecal oocysts and slight lesions were observed. NZL significantly promoted weight gain (WG) and reduced lesion scores (LS) compared to controls receiving diclazuril (DZL) ( P E. tenella , Eimeria necatrix , Eimeria acervulina and Eimeria maxima , respectively, whereas those of DZL-treated groups were 185, 176, 176 and 148. In the cross-drug resistance study (study C), ACIs of NZL and toltrazuril (TZL)-treated groups ranged from 188 to 204, which were significantly higher than those of DZL-treated groups ( P E. tenella , whereas DZL-treated groups showed complete resistance. No cross-resistance was observed between DZL and NZL or TZL. Based on the abovementioned studies, it was concluded that diets containing 3 mg/kg NZL had an excellent efficacy in preventing coccidiosis in broiler chickens. The activity of 3 mg/kg NZL in the diet was equal or superior to that of 1 mg/kg DZL. These results are of great significance for the future applications of NZL; however, its actual mechanism of action remains unknown. NZL is a potential novel Anticoccidial agent suitable for further development.
Snorre Stuen - One of the best experts on this subject based on the ideXlab platform.
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preliminary studies on in vitro methods for the evaluation of Anticoccidial efficacy resistance in ruminants
Experimental Parasitology, 2019Co-Authors: Ane Odden, Snorre Stuen, Heidi L. Enemark, Lucy J. Robertson, J.m. Molina, Antonio RuizAbstract:Ovine Eimeria spp. infections cause increased mortality, reduced welfare and substantial economic losses, and anticocccidials are important for their control. Recent reports of Anticoccidial resistance against ovine Eimeria spp. necessitate the development of in vitro methods for the detection of reduced Anticoccidial efficacy, especially since the in vivo methods are both expensive, time consuming and requires the use of otherwise healthy animals. The aim of the present study was therefore to approach a preliminary standardization of in vitro assays for evaluation of the efficacy of the most commonly used Anticoccidials in ruminants. For this purpose, apart from the evaluation of inhibition of oocyst sporulation, most effort was concentrated on assessment of the capacity of the different Anticoccidials to inhibit both the invasion and further development (up to the first schizogony) of E. ninakohlyakimovae sporozoites in bovine colonic epithelial cells (BCEC). For this purpose, infected cultures were monitored 1, 8 and 15 days post infection to determine the infection rate, number of immature schizonts and number, size and appearance of mature schizonts, respectively. No clear inhibitory effect was found with any of the Anticoccidial formulations tested, and we could not identify why there were no measurable effects from the different Anticoccidials. Despite the lack of positive results, further investigations should be encouraged, as this could decrease the need for animal experiments and could be used in the initial assessment of Anticoccidial efficacy of new drugs.
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Preliminary studies on in vitro methods for the evaluation of Anticoccidial efficacy/resistance in ruminants.
Experimental parasitology, 2019Co-Authors: Ane Odden, Snorre Stuen, Heidi L. Enemark, Lucy J. Robertson, J.m. Molina, Antonio RuizAbstract:Ovine Eimeria spp. infections cause increased mortality, reduced welfare and substantial economic losses, and anticocccidials are important for their control. Recent reports of Anticoccidial resistance against ovine Eimeria spp. necessitate the development of in vitro methods for the detection of reduced Anticoccidial efficacy, especially since the in vivo methods are both expensive, time consuming and requires the use of otherwise healthy animals. The aim of the present study was therefore to approach a preliminary standardization of in vitro assays for evaluation of the efficacy of the most commonly used Anticoccidials in ruminants. For this purpose, apart from the evaluation of inhibition of oocyst sporulation, most effort was concentrated on assessment of the capacity of the different Anticoccidials to inhibit both the invasion and further development (up to the first schizogony) of E. ninakohlyakimovae sporozoites in bovine colonic epithelial cells (BCEC). For this purpose, infected cultures were monitored 1, 8 and 15 days post infection to determine the infection rate, number of immature schizonts and number, size and appearance of mature schizonts, respectively. No clear inhibitory effect was found with any of the Anticoccidial formulations tested, and we could not identify why there were no measurable effects from the different Anticoccidials. Despite the lack of positive results, further investigations should be encouraged, as this could decrease the need for animal experiments and could be used in the initial assessment of Anticoccidial efficacy of new drugs.
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field evaluation of Anticoccidial efficacy a novel approach demonstrates reduced efficacy of toltrazuril against ovine eimeria spp in norway
International Journal for Parasitology-Drugs and Drug Resistance, 2018Co-Authors: Ane Odden, Snorre Stuen, Lucy J. Robertson, Lisbeth Hektoen, Matthew Denwood, A Ruiz, Inger Sofie Hamnes, Heidi L. EnemarkAbstract:Abstract Ovine Eimeria spp. infections cause reduced welfare, increased mortality, and substantial economic losses, and Anticoccidials are crucial for their control. Recent reports of toltrazuril resistance in pigs, and anecdotal reports of reduced Anticoccidial efficacy in lambs, necessitate evaluation of Anticoccidial efficacy. Due to the substantial lifecycle differences between nematodes and coccidia, current WAAVP methods for assessing anthelmintic efficacy are not suitable for such evaluations. Faecal samples were collected from 8 pairs of twin lambs from 36 Norwegian sheep farms 6–8 days after turnout. One twin of each pair was then treated with 20 mg/kg toltrazuril and a second faecal sample from all lambs was collected 7–11 days later. Oocyst excretion rate in all samples was determined using McMasters. Suitability of treatment timing was investigated by evaluating the increase in mean log oocyst excretion in untreated lambs. Based on comparisons between groups, a threshold of ≥0.75 (13 farms) was used to identify farms where drug efficacy could be assessed with confidence, drug efficacy on farms with increases of ≥0.5 but 90%), and for 5 the results were inconclusive. This is the first evidence-based report of reduced Anticoccidial efficacy in ovine Eimeria spp. Additionally, we highlight the problem of sub-optimal timing of treatment (16/36 farms), which could potentially result in incorrect conclusions being reached regarding lack of drug efficacy.
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Controlled efficacy trial confirming toltrazuril resistance in a field isolate of ovine Eimeria spp.
Parasites & Vectors, 2018Co-Authors: Ane Odden, Heidi L. Enemark, Lucy J. Robertson, Antonio Ruiz, Cecilie Ersdal, Silje Katrine Nes, Vibeke Tømmerberg, Snorre StuenAbstract:Coccidiosis due to Eimeria spp. infections in lambs causes increased mortality and substantial production losses, and Anticoccidials are important for control of the infection. Anticoccidial resistance has been reported in poultry and swine, and we recently described reduced toltrazuril efficacy in ovine Eimeria spp. in some Norwegian sheep farms using a newly developed faecal oocyst count reduction test (FOCRT). The aim of the present study was to use a controlled efficacy trial to assess the efficacy of toltrazuril against a field isolate suspected of being resistant. Twenty lambs, 17–22 days old and raised protected against exposure to coccidia, were infected with a field isolate of 100,000 Eimeria spp. oocysts. This isolate was obtained from a farm with a previously calculated drug efficacy of 56% (95% confidence interval: -433.9 to 96.6%). At day 7 post-infection, 10 of the lambs were orally treated with 20 mg/kg toltrazuril (Baycox Sheep vet., Bayer Animal Health), while the other 10 lambs (controls) were given physiological saline. Clinical examinations were conducted, and weight gains recorded. Daily faecal samples were scored for diarrhoea on a scale from 1 to 5, and oocyst excretion was determined using a modified McMaster technique. Oocysts were morphologically identified to species level. At 17–24 days post-infection, the lambs were euthanized and necropsied. The tested Eimeria isolate was resistant against toltrazuril, and resistance was seen in both pathogenic and non-pathogenic species. In addition, no significant differences in faecal score, growth, gross pathology or histological changes were identified between the two groups. The pathogenic E. ovinoidalis was the dominant species, and no significant difference in the individual prevalence of E. ovinoidalis post-treatment was found between treated (66.9%) and control lambs (61.9%). Other species identified included E. crandallis/weybridgensis, E. parva, E. marsica, E. faurei, E. pallida, E. ahsata and E. bakuensis. This study confirms toltrazuril resistance in ovine Eimeria spp.; in addition, the data support the use of FOCRT as an appropriate tool for field evaluation of Anticoccidial efficacy. Due to limited Anticoccidial treatment alternatives, these findings may have important implications for the sheep industry, particularly in northern Europe.
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Field evaluation of Anticoccidial efficacy: A novel approach demonstrates reduced efficacy of toltrazuril against ovine Eimeria spp. in Norway
Elsevier, 2018Co-Authors: Ane Odden, Snorre Stuen, Lucy J. Robertson, Antonio Ruiz, Lisbeth Hektoen, Matthew Denwood, Inger Sofie Hamnes, Heidi L. EnemarkAbstract:Ovine Eimeria spp. infections cause reduced welfare, increased mortality, and substantial economic losses, and Anticoccidials are crucial for their control. Recent reports of toltrazuril resistance in pigs, and anecdotal reports of reduced Anticoccidial efficacy in lambs, necessitate evaluation of Anticoccidial efficacy. Due to the substantial lifecycle differences between nematodes and coccidia, current WAAVP methods for assessing anthelmintic efficacy are not suitable for such evaluations. Faecal samples were collected from 8 pairs of twin lambs from 36 Norwegian sheep farms 6–8 days after turnout. One twin of each pair was then treated with 20 mg/kg toltrazuril and a second faecal sample from all lambs was collected 7–11 days later. Oocyst excretion rate in all samples was determined using McMasters. Suitability of treatment timing was investigated by evaluating the increase in mean log oocyst excretion in untreated lambs. Based on comparisons between groups, a threshold of ≥0.75 (13 farms) was used to identify farms where drug efficacy could be assessed with confidence, drug efficacy on farms with increases of ≥0.5 but
Ane Odden - One of the best experts on this subject based on the ideXlab platform.
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preliminary studies on in vitro methods for the evaluation of Anticoccidial efficacy resistance in ruminants
Experimental Parasitology, 2019Co-Authors: Ane Odden, Snorre Stuen, Heidi L. Enemark, Lucy J. Robertson, J.m. Molina, Antonio RuizAbstract:Ovine Eimeria spp. infections cause increased mortality, reduced welfare and substantial economic losses, and anticocccidials are important for their control. Recent reports of Anticoccidial resistance against ovine Eimeria spp. necessitate the development of in vitro methods for the detection of reduced Anticoccidial efficacy, especially since the in vivo methods are both expensive, time consuming and requires the use of otherwise healthy animals. The aim of the present study was therefore to approach a preliminary standardization of in vitro assays for evaluation of the efficacy of the most commonly used Anticoccidials in ruminants. For this purpose, apart from the evaluation of inhibition of oocyst sporulation, most effort was concentrated on assessment of the capacity of the different Anticoccidials to inhibit both the invasion and further development (up to the first schizogony) of E. ninakohlyakimovae sporozoites in bovine colonic epithelial cells (BCEC). For this purpose, infected cultures were monitored 1, 8 and 15 days post infection to determine the infection rate, number of immature schizonts and number, size and appearance of mature schizonts, respectively. No clear inhibitory effect was found with any of the Anticoccidial formulations tested, and we could not identify why there were no measurable effects from the different Anticoccidials. Despite the lack of positive results, further investigations should be encouraged, as this could decrease the need for animal experiments and could be used in the initial assessment of Anticoccidial efficacy of new drugs.
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Preliminary studies on in vitro methods for the evaluation of Anticoccidial efficacy/resistance in ruminants.
Experimental parasitology, 2019Co-Authors: Ane Odden, Snorre Stuen, Heidi L. Enemark, Lucy J. Robertson, J.m. Molina, Antonio RuizAbstract:Ovine Eimeria spp. infections cause increased mortality, reduced welfare and substantial economic losses, and anticocccidials are important for their control. Recent reports of Anticoccidial resistance against ovine Eimeria spp. necessitate the development of in vitro methods for the detection of reduced Anticoccidial efficacy, especially since the in vivo methods are both expensive, time consuming and requires the use of otherwise healthy animals. The aim of the present study was therefore to approach a preliminary standardization of in vitro assays for evaluation of the efficacy of the most commonly used Anticoccidials in ruminants. For this purpose, apart from the evaluation of inhibition of oocyst sporulation, most effort was concentrated on assessment of the capacity of the different Anticoccidials to inhibit both the invasion and further development (up to the first schizogony) of E. ninakohlyakimovae sporozoites in bovine colonic epithelial cells (BCEC). For this purpose, infected cultures were monitored 1, 8 and 15 days post infection to determine the infection rate, number of immature schizonts and number, size and appearance of mature schizonts, respectively. No clear inhibitory effect was found with any of the Anticoccidial formulations tested, and we could not identify why there were no measurable effects from the different Anticoccidials. Despite the lack of positive results, further investigations should be encouraged, as this could decrease the need for animal experiments and could be used in the initial assessment of Anticoccidial efficacy of new drugs.
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field evaluation of Anticoccidial efficacy a novel approach demonstrates reduced efficacy of toltrazuril against ovine eimeria spp in norway
International Journal for Parasitology-Drugs and Drug Resistance, 2018Co-Authors: Ane Odden, Snorre Stuen, Lucy J. Robertson, Lisbeth Hektoen, Matthew Denwood, A Ruiz, Inger Sofie Hamnes, Heidi L. EnemarkAbstract:Abstract Ovine Eimeria spp. infections cause reduced welfare, increased mortality, and substantial economic losses, and Anticoccidials are crucial for their control. Recent reports of toltrazuril resistance in pigs, and anecdotal reports of reduced Anticoccidial efficacy in lambs, necessitate evaluation of Anticoccidial efficacy. Due to the substantial lifecycle differences between nematodes and coccidia, current WAAVP methods for assessing anthelmintic efficacy are not suitable for such evaluations. Faecal samples were collected from 8 pairs of twin lambs from 36 Norwegian sheep farms 6–8 days after turnout. One twin of each pair was then treated with 20 mg/kg toltrazuril and a second faecal sample from all lambs was collected 7–11 days later. Oocyst excretion rate in all samples was determined using McMasters. Suitability of treatment timing was investigated by evaluating the increase in mean log oocyst excretion in untreated lambs. Based on comparisons between groups, a threshold of ≥0.75 (13 farms) was used to identify farms where drug efficacy could be assessed with confidence, drug efficacy on farms with increases of ≥0.5 but 90%), and for 5 the results were inconclusive. This is the first evidence-based report of reduced Anticoccidial efficacy in ovine Eimeria spp. Additionally, we highlight the problem of sub-optimal timing of treatment (16/36 farms), which could potentially result in incorrect conclusions being reached regarding lack of drug efficacy.
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Controlled efficacy trial confirming toltrazuril resistance in a field isolate of ovine Eimeria spp.
Parasites & Vectors, 2018Co-Authors: Ane Odden, Heidi L. Enemark, Lucy J. Robertson, Antonio Ruiz, Cecilie Ersdal, Silje Katrine Nes, Vibeke Tømmerberg, Snorre StuenAbstract:Coccidiosis due to Eimeria spp. infections in lambs causes increased mortality and substantial production losses, and Anticoccidials are important for control of the infection. Anticoccidial resistance has been reported in poultry and swine, and we recently described reduced toltrazuril efficacy in ovine Eimeria spp. in some Norwegian sheep farms using a newly developed faecal oocyst count reduction test (FOCRT). The aim of the present study was to use a controlled efficacy trial to assess the efficacy of toltrazuril against a field isolate suspected of being resistant. Twenty lambs, 17–22 days old and raised protected against exposure to coccidia, were infected with a field isolate of 100,000 Eimeria spp. oocysts. This isolate was obtained from a farm with a previously calculated drug efficacy of 56% (95% confidence interval: -433.9 to 96.6%). At day 7 post-infection, 10 of the lambs were orally treated with 20 mg/kg toltrazuril (Baycox Sheep vet., Bayer Animal Health), while the other 10 lambs (controls) were given physiological saline. Clinical examinations were conducted, and weight gains recorded. Daily faecal samples were scored for diarrhoea on a scale from 1 to 5, and oocyst excretion was determined using a modified McMaster technique. Oocysts were morphologically identified to species level. At 17–24 days post-infection, the lambs were euthanized and necropsied. The tested Eimeria isolate was resistant against toltrazuril, and resistance was seen in both pathogenic and non-pathogenic species. In addition, no significant differences in faecal score, growth, gross pathology or histological changes were identified between the two groups. The pathogenic E. ovinoidalis was the dominant species, and no significant difference in the individual prevalence of E. ovinoidalis post-treatment was found between treated (66.9%) and control lambs (61.9%). Other species identified included E. crandallis/weybridgensis, E. parva, E. marsica, E. faurei, E. pallida, E. ahsata and E. bakuensis. This study confirms toltrazuril resistance in ovine Eimeria spp.; in addition, the data support the use of FOCRT as an appropriate tool for field evaluation of Anticoccidial efficacy. Due to limited Anticoccidial treatment alternatives, these findings may have important implications for the sheep industry, particularly in northern Europe.
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Field evaluation of Anticoccidial efficacy: A novel approach demonstrates reduced efficacy of toltrazuril against ovine Eimeria spp. in Norway
Elsevier, 2018Co-Authors: Ane Odden, Snorre Stuen, Lucy J. Robertson, Antonio Ruiz, Lisbeth Hektoen, Matthew Denwood, Inger Sofie Hamnes, Heidi L. EnemarkAbstract:Ovine Eimeria spp. infections cause reduced welfare, increased mortality, and substantial economic losses, and Anticoccidials are crucial for their control. Recent reports of toltrazuril resistance in pigs, and anecdotal reports of reduced Anticoccidial efficacy in lambs, necessitate evaluation of Anticoccidial efficacy. Due to the substantial lifecycle differences between nematodes and coccidia, current WAAVP methods for assessing anthelmintic efficacy are not suitable for such evaluations. Faecal samples were collected from 8 pairs of twin lambs from 36 Norwegian sheep farms 6–8 days after turnout. One twin of each pair was then treated with 20 mg/kg toltrazuril and a second faecal sample from all lambs was collected 7–11 days later. Oocyst excretion rate in all samples was determined using McMasters. Suitability of treatment timing was investigated by evaluating the increase in mean log oocyst excretion in untreated lambs. Based on comparisons between groups, a threshold of ≥0.75 (13 farms) was used to identify farms where drug efficacy could be assessed with confidence, drug efficacy on farms with increases of ≥0.5 but
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preliminary studies on in vitro methods for the evaluation of Anticoccidial efficacy resistance in ruminants
Experimental Parasitology, 2019Co-Authors: Ane Odden, Snorre Stuen, Heidi L. Enemark, Lucy J. Robertson, J.m. Molina, Antonio RuizAbstract:Ovine Eimeria spp. infections cause increased mortality, reduced welfare and substantial economic losses, and anticocccidials are important for their control. Recent reports of Anticoccidial resistance against ovine Eimeria spp. necessitate the development of in vitro methods for the detection of reduced Anticoccidial efficacy, especially since the in vivo methods are both expensive, time consuming and requires the use of otherwise healthy animals. The aim of the present study was therefore to approach a preliminary standardization of in vitro assays for evaluation of the efficacy of the most commonly used Anticoccidials in ruminants. For this purpose, apart from the evaluation of inhibition of oocyst sporulation, most effort was concentrated on assessment of the capacity of the different Anticoccidials to inhibit both the invasion and further development (up to the first schizogony) of E. ninakohlyakimovae sporozoites in bovine colonic epithelial cells (BCEC). For this purpose, infected cultures were monitored 1, 8 and 15 days post infection to determine the infection rate, number of immature schizonts and number, size and appearance of mature schizonts, respectively. No clear inhibitory effect was found with any of the Anticoccidial formulations tested, and we could not identify why there were no measurable effects from the different Anticoccidials. Despite the lack of positive results, further investigations should be encouraged, as this could decrease the need for animal experiments and could be used in the initial assessment of Anticoccidial efficacy of new drugs.
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Preliminary studies on in vitro methods for the evaluation of Anticoccidial efficacy/resistance in ruminants.
Experimental parasitology, 2019Co-Authors: Ane Odden, Snorre Stuen, Heidi L. Enemark, Lucy J. Robertson, J.m. Molina, Antonio RuizAbstract:Ovine Eimeria spp. infections cause increased mortality, reduced welfare and substantial economic losses, and anticocccidials are important for their control. Recent reports of Anticoccidial resistance against ovine Eimeria spp. necessitate the development of in vitro methods for the detection of reduced Anticoccidial efficacy, especially since the in vivo methods are both expensive, time consuming and requires the use of otherwise healthy animals. The aim of the present study was therefore to approach a preliminary standardization of in vitro assays for evaluation of the efficacy of the most commonly used Anticoccidials in ruminants. For this purpose, apart from the evaluation of inhibition of oocyst sporulation, most effort was concentrated on assessment of the capacity of the different Anticoccidials to inhibit both the invasion and further development (up to the first schizogony) of E. ninakohlyakimovae sporozoites in bovine colonic epithelial cells (BCEC). For this purpose, infected cultures were monitored 1, 8 and 15 days post infection to determine the infection rate, number of immature schizonts and number, size and appearance of mature schizonts, respectively. No clear inhibitory effect was found with any of the Anticoccidial formulations tested, and we could not identify why there were no measurable effects from the different Anticoccidials. Despite the lack of positive results, further investigations should be encouraged, as this could decrease the need for animal experiments and could be used in the initial assessment of Anticoccidial efficacy of new drugs.
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field evaluation of Anticoccidial efficacy a novel approach demonstrates reduced efficacy of toltrazuril against ovine eimeria spp in norway
International Journal for Parasitology-Drugs and Drug Resistance, 2018Co-Authors: Ane Odden, Snorre Stuen, Lucy J. Robertson, Lisbeth Hektoen, Matthew Denwood, A Ruiz, Inger Sofie Hamnes, Heidi L. EnemarkAbstract:Abstract Ovine Eimeria spp. infections cause reduced welfare, increased mortality, and substantial economic losses, and Anticoccidials are crucial for their control. Recent reports of toltrazuril resistance in pigs, and anecdotal reports of reduced Anticoccidial efficacy in lambs, necessitate evaluation of Anticoccidial efficacy. Due to the substantial lifecycle differences between nematodes and coccidia, current WAAVP methods for assessing anthelmintic efficacy are not suitable for such evaluations. Faecal samples were collected from 8 pairs of twin lambs from 36 Norwegian sheep farms 6–8 days after turnout. One twin of each pair was then treated with 20 mg/kg toltrazuril and a second faecal sample from all lambs was collected 7–11 days later. Oocyst excretion rate in all samples was determined using McMasters. Suitability of treatment timing was investigated by evaluating the increase in mean log oocyst excretion in untreated lambs. Based on comparisons between groups, a threshold of ≥0.75 (13 farms) was used to identify farms where drug efficacy could be assessed with confidence, drug efficacy on farms with increases of ≥0.5 but 90%), and for 5 the results were inconclusive. This is the first evidence-based report of reduced Anticoccidial efficacy in ovine Eimeria spp. Additionally, we highlight the problem of sub-optimal timing of treatment (16/36 farms), which could potentially result in incorrect conclusions being reached regarding lack of drug efficacy.
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Controlled efficacy trial confirming toltrazuril resistance in a field isolate of ovine Eimeria spp.
Parasites & Vectors, 2018Co-Authors: Ane Odden, Heidi L. Enemark, Lucy J. Robertson, Antonio Ruiz, Cecilie Ersdal, Silje Katrine Nes, Vibeke Tømmerberg, Snorre StuenAbstract:Coccidiosis due to Eimeria spp. infections in lambs causes increased mortality and substantial production losses, and Anticoccidials are important for control of the infection. Anticoccidial resistance has been reported in poultry and swine, and we recently described reduced toltrazuril efficacy in ovine Eimeria spp. in some Norwegian sheep farms using a newly developed faecal oocyst count reduction test (FOCRT). The aim of the present study was to use a controlled efficacy trial to assess the efficacy of toltrazuril against a field isolate suspected of being resistant. Twenty lambs, 17–22 days old and raised protected against exposure to coccidia, were infected with a field isolate of 100,000 Eimeria spp. oocysts. This isolate was obtained from a farm with a previously calculated drug efficacy of 56% (95% confidence interval: -433.9 to 96.6%). At day 7 post-infection, 10 of the lambs were orally treated with 20 mg/kg toltrazuril (Baycox Sheep vet., Bayer Animal Health), while the other 10 lambs (controls) were given physiological saline. Clinical examinations were conducted, and weight gains recorded. Daily faecal samples were scored for diarrhoea on a scale from 1 to 5, and oocyst excretion was determined using a modified McMaster technique. Oocysts were morphologically identified to species level. At 17–24 days post-infection, the lambs were euthanized and necropsied. The tested Eimeria isolate was resistant against toltrazuril, and resistance was seen in both pathogenic and non-pathogenic species. In addition, no significant differences in faecal score, growth, gross pathology or histological changes were identified between the two groups. The pathogenic E. ovinoidalis was the dominant species, and no significant difference in the individual prevalence of E. ovinoidalis post-treatment was found between treated (66.9%) and control lambs (61.9%). Other species identified included E. crandallis/weybridgensis, E. parva, E. marsica, E. faurei, E. pallida, E. ahsata and E. bakuensis. This study confirms toltrazuril resistance in ovine Eimeria spp.; in addition, the data support the use of FOCRT as an appropriate tool for field evaluation of Anticoccidial efficacy. Due to limited Anticoccidial treatment alternatives, these findings may have important implications for the sheep industry, particularly in northern Europe.
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Field evaluation of Anticoccidial efficacy: A novel approach demonstrates reduced efficacy of toltrazuril against ovine Eimeria spp. in Norway
Elsevier, 2018Co-Authors: Ane Odden, Snorre Stuen, Lucy J. Robertson, Antonio Ruiz, Lisbeth Hektoen, Matthew Denwood, Inger Sofie Hamnes, Heidi L. EnemarkAbstract:Ovine Eimeria spp. infections cause reduced welfare, increased mortality, and substantial economic losses, and Anticoccidials are crucial for their control. Recent reports of toltrazuril resistance in pigs, and anecdotal reports of reduced Anticoccidial efficacy in lambs, necessitate evaluation of Anticoccidial efficacy. Due to the substantial lifecycle differences between nematodes and coccidia, current WAAVP methods for assessing anthelmintic efficacy are not suitable for such evaluations. Faecal samples were collected from 8 pairs of twin lambs from 36 Norwegian sheep farms 6–8 days after turnout. One twin of each pair was then treated with 20 mg/kg toltrazuril and a second faecal sample from all lambs was collected 7–11 days later. Oocyst excretion rate in all samples was determined using McMasters. Suitability of treatment timing was investigated by evaluating the increase in mean log oocyst excretion in untreated lambs. Based on comparisons between groups, a threshold of ≥0.75 (13 farms) was used to identify farms where drug efficacy could be assessed with confidence, drug efficacy on farms with increases of ≥0.5 but