Side effects of abamectin and hexythiazox on seven predatory mites / Efeitos colaterais da abamectina e hexitiazox em sete ácaros predadores

Use of acaricides has become a common practice to control pests all over the world including Saudi Arabia. In spite of killing the targeted pests, such insecticides also effect growth of predatory mites. Present study has been conducted to evaluate the impact of two acaricides, abamectin and hexythiazox, on seven species of predatory mites. Standard solutions of abamectin (8.4% w/v) and hexythiazox (10% w/w) were purchased and prepared for direct spray. Acaricides were tested at three serial concentrations of recommended dose (RD), half of the recommended dose (HRD) and double the recommended dose (DRD). Trials were made on eggs, nymphs and adults of the seven species of predatory mites under laboratory conditions. Effect of the applied acaricides was determined one week after the application. The results of the study revealed that all doses of hexythiazox and abamectin are toxic to the nymphs and adults of all seven species of predatory mites but to the variable extent. Furthermore, it was observed that hexythiazox and abamectin reduced the percentage of egg hatching for all seven species of predatory mites. Hexythiazox was found to be more toxic than abamectin to all seven predatory mites. Higher mortality was recorded at DRD and RD, while minimum mortality was recorded at HRD. Acaricidal effect is less severe on hatching eggs than on immatures and adults of the predatory mites. Species vary in susceptibility to acaricides and in some populations resistance has been observed. Based upon this study, it is recommended that the frequent use of acaricides against phytophagous mites should be avoided and feasibility of biological control programs should be promoted to protect the environment, health of living individuals and the non-target organisms.

O uso de acaricidas se tornou prática comum para o controle de pragas em todo o mundo, incluindo a Arábia Saudita. Apesar de matar as pragas-alvo, esses inseticidas também afetam o crescimento de ácaros predadores. O presente estudo foi conduzido para avaliar o impacto de dois acaricidas, abamectina e hexythiazox, em sete espécies de ácaros predadores. Soluções padrão de abamectina (8.4% w/v) e hexitiazox (10% w/w) foram adquiridas e preparadas para pulverização direta. Os acaricidas foram testados em três concentrações seriais de dose recomendada (RD), metade da dose recomendada (HRD) e o dobro da dose recomendada (DRD). Os ensaios foram feitos em ovos, ninfas e adultos das sete espécies de ácaros predadores em condições de laboratório. O efeito dos acaricidas aplicados foi determinado uma semana após a aplicação. Os resultados do estudo revelaram que todas as doses de hexitiazox e abamectina são tóxicas para as ninfas e adultos de todas as sete espécies de ácaros predadores, mas em extensão variável. Além disso, foi observado que hexitiazox e abamectina reduziram a porcentagem de eclosão de ovos para todas as sete espécies de ácaros predadores. Verificou-se que o hexitiazox é mais tóxico do que a abamectinapara todos os sete ácaros predadores. A mortalidade mais alta foi registrada no DRD e RD, enquanto a mortalidade mínima foi registrada no HRD. O efeito acaricida é menos severo em ovos para incubação do que em imaturos e adultos de ácaros predadores. As espécies variam em suscetibilidade a acaricidas, e em algumas populações foi observada resistência. Com base neste estudo, recomenda-se que o uso frequente de acaricidas contra ácaros fitófagos seja evitado e a viabilidade de programas de controle biológico seja promovida para proteger o meio ambiente, a saúde de indivíduos vivos e de organismos não visados.

Side effects of abamectin and hexythiazox on seven predatory mites

Abstract Use of acaricides has become a common practice to control pests all over the world including Saudi Arabia. In spite of killing the targeted pests, such insecticides also effect growth of predatory mites. Present study has been conducted to evaluate the impact of two acaricides, abamectin and hexythiazox, on seven species of predatory mites. Standard solutions of abamectin (8.4% w/v) and hexythiazox (10% w/w) were purchased and prepared for direct spray. Acaricides were tested at three serial concentrations of recommended dose (RD), half of the recommended dose (HRD) and double the recommended dose (DRD). Trials were made on eggs, nymphs and adults of the seven species of predatory mites under laboratory conditions. Effect of the applied acaricides was determined one week after the application. The results of the study revealed that all doses of hexythiazox and abamectin are toxic to the nymphs and adults of all seven species of predatory mites but to the variable extent. Furthermore, it was observed that hexythiazox and abamectin reduced the percentage of egg hatching for all seven species of predatory mites. Hexythiazox was found to be more toxic than abamectin to all seven predatory mites. Higher mortality was recorded at DRD and RD, while minimum mortality was recorded at HRD. Acaricidal effect is less severe on hatching eggs than on immatures and adults of the predatory mites. Species vary in susceptibility to acaricides and in some populations resistance has been observed. Based upon this study, it is recommended that the frequent use of acaricides against phytophagous mites should be avoided and feasibility of biological control programs should be promoted to protect the environment, health of living individuals and the non-target organisms.

Resumo O uso de acaricidas se tornou prática comum para o controle de pragas em todo o mundo, incluindo a Arábia Saudita. Apesar de matar as pragas-alvo, esses inseticidas também afetam o crescimento de ácaros predadores. O presente estudo foi conduzido para avaliar o impacto de dois acaricidas, abamectina e hexythiazox, em sete espécies de ácaros predadores. Soluções padrão de abamectina (8.4% w/v) e hexitiazox (10% w/w) foram adquiridas e preparadas para pulverização direta. Os acaricidas foram testados em três concentrações seriais de dose recomendada (RD), metade da dose recomendada (HRD) e o dobro da dose recomendada (DRD). Os ensaios foram feitos em ovos, ninfas e adultos das sete espécies de ácaros predadores em condições de laboratório. O efeito dos acaricidas aplicados foi determinado uma semana após a aplicação. Os resultados do estudo revelaram que todas as doses de hexitiazox e abamectina são tóxicas para as ninfas e adultos de todas as sete espécies de ácaros predadores, mas em extensão variável. Além disso, foi observado que hexitiazox e abamectina reduziram a porcentagem de eclosão de ovos para todas as sete espécies de ácaros predadores. Verificou-se que o hexitiazox é mais tóxico do que a abamectina para todos os sete ácaros predadores. A mortalidade mais alta foi registrada no DRD e RD, enquanto a mortalidade mínima foi registrada no HRD. O efeito acaricida é menos severo em ovos para incubação do que em imaturos e adultos de ácaros predadores. As espécies variam em suscetibilidade a acaricidas, e em algumas populações foi observada resistência. Com base neste estudo, recomenda-se que o uso frequente de acaricidas contra ácaros fitófagos seja evitado e a viabilidade de programas de controle biológico seja promovida para proteger o meio ambiente, a saúde de indivíduos vivos e de organismos não visados.

Eficacia de la combinación de Abamectina-Derquantel y de la Moxidectina en cabras lecheras naturalmente parasitadas con nematodos gastrointestinales en el Valle de Lerma, Argentina / Efficacy of combining Abamectin-Derquantel and Moxidectin in dairy goats naturally infected by gastrointstinal nematodes in Valle de Lerma, Argentina

Resumen El impacto productivo de los nematodos gastrointestinales (NGI) sobre los de pequeños rumiantes es conocido a nivel mundial. Las infestaciones por NGI constituyen una limitante de alto impacto en la producción de rumiantes y las perdidas comprendidas por este problema sanitario varían desde reducciones subclínicas en la ganancia de peso hasta la muerte de animales con altas cargas parasitarias. El objetivo de este trabajo es presentar los resultados de un test de eficacia a campo utilizando una combinación comercial de Abamectina + Derquantel y del Moxidectin en cabras lecheras naturalmente infestadas con NGI en el Valle de Lerma, provincia de Salta. El ensayo se llevó a cabo en la Unidad Tambo Caprino de la Estación Experimental Agropecuaria Salta del INTA. Para la evaluación de eficacia de la droga en estudio, se realizó el test de reducción de conteos de huevos. En los coprocultivos pre-tratamientos se pudo observar una gran prevalencia de Trichostrongylus spp. (71%). seguido de Teladorsagia spp. (21%) y Haemonchus spp. (8%). En cuanto a los resultados del TRCH, en el GDQ se observaron valores del 100% de PRCH, mientras que en el GMX se observó un PRCH de 95,5 %, donde la eficacia para Haemonchus spp. y Teladorsagiaspp. fue del 100% y para Trichostrongylus spp. del 81,1%.Los resultados observados en este trabajo permiten concluir que en las condiciones de campo en donde fue llevado a cabo el TRCH, la combinación Derquantel-Abamectina posee una alta eficacia contra los géneros presentes.

Abstract The productive impact of gastrointestinal nematodes (NGI) of small ruminants are known worldwide. Infestations by NGI constitute a limiting factor in the production of ruminant and the losses included by this sanitary problem vary from subclinical reductions in weight gain to the death of animals with high parasite loads. The objective of this work is to present the results of an efficacy trial using a commercial combination of Abamectin + Derquantel and Moxidectin in dairy goats naturally infested with NGI in the Lerma Valley, Salta province. The test was carried out in the Dairy Goat Unit of the Salta Agricultural Experiment Station of INTA. In the pretreatment stool cultures, a high prevalence of Trichostrongylusspp. (71%). followed by Teladorsagiaspp. (21%) and Haemonchus spp. (8%) was observed. Regarding the results of the TRCH, in the GDQ values ​​of 100% of PRCH were observed, while in the GMX a PRCH of 95.5% is shown, where the efficacy for Haemonchus spp. and Teladorsagia spp. was 100% and for Trichostrongylus spp. 81.1%. The results observed in this work allow us to conclude that under the field conditions where TRCH was carried out, the Derquantel-Abamectin combination has high efficacy against the genera present.

Approaches for a field diagnosis of abamectin poisoning in calves / Abordagem para um diagnóstico a campo da intoxicação por abamectina em bezerros

An approach for the diagnosis of an abamectin outbreak in calves in the field is described and discussed. In a Midwestern Brazilian property, nine out of a 52 newborn calves were affected and died, making up for morbidity, mortality, and lethality ratios of 17.3%, 17.3%, and 100%, respectively. Major clinical signs included tremors in various muscle groups, inability to stand, and difficult, wheezing breathing. Each affected calf had been treated subcutaneously with abamectin (0.4mg/kg/body weight). No lesions were found at necropsy or at histological examination. Major diseases of newborn calves were included in the differential diagnosis.(AU)

Uma abordagem para o diagnóstico de um surto de abamectina em bezerros a campo é descrita e discutida. Numa propriedade do Centro-Oeste brasileiro, nove de um lote de 52 bezerros de 3 dias de idade foram afetados e morreram, perfazendo quocientes de morbidade, mortalidade e letalidade, respectivamente, de 17,3%, 17,3% e 100%. Os principais sinais clínicos incluíam tremores em vários grupos musculares, incapacidade em se manter em pé, e respiração difícil e estertorosa. Cada bezerro afetado havia sido tratado por via subcutânea com abamectina, na dose de 0,4mg/kg/peso corporal. Não foram encontradas lesões na necropsia, nem no exame histológico. As principais doenças de bezerros recém-nascidos foram incluídas no diagnóstico diferencial.(AU)

Sublethal effect of Abamectin in the functional response of the predator Phytoseiulus persimilis (Athias-Henriot) on Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae) / Efeito subletal da Abamectina na resposta funcional do predador Phytoseiulus persimilis (Athias-Henriot) em Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae)

Abstract The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a'), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.

Resumo O controle biológico utilizado para o controle de Tetranychus urticae (Koch) é o acaro predador Phytoseiulus persimilis (Athias-Henriot). É importante conhecer os efeitos dos acaricidas sobre o comportamento biológico do predador. Foi avaliado o efeito tóxico de a Abamectina na resposta funcional de P. persimilis. A resposta funcional do predador foi tipo II exposta a concentrações subletais de Abacmetina, os parâmetros da resposta funcional: taxa de ataque (a'), tempo de manipulação (Th), a eficiência na procura e predação teórica máxima (T/Th) foram afetados pelo acaricida. O predador passa mais tempo na procura, dominar, consumir e se preparar para a próxima procura em comparação com a testemunha e sua capacidade de predação foi afetada.

Subcritical Butane Extraction for Effective Removalof Abamectin in Fresh Tea Leaves / 分析化学

Subcritical butane technology was employed for the separation of abamectin on the fresh tea leaves surface.Under the conditions of solid-liquid ratio of 1∶10 (m/V), the experiment was designed via the response surface methodology and conducted at different temperature, various separation time and discrepant cycle number.Besides, the activity of the polyphenol oxidase (PPO) relating to the quality of the tea was determined and compared.At the same time, scanning electron microscopy (SEM) was used to observe the surface structure of fresh tea leaves before and after treatment, and the effect on physiological characteristics of the leaves by subcritical butane treatment was analyzed.The experimental results showed that the subcritical butane extraction could effectively isolate the abamectin, making the physical structure basically remained and the polyphenol oxidase activity preserved as well.Through the analysis by Design Expert software, the optimal processing parameters of separating abamectin were as follows: 45℃, 30 min, 1 cycle, and solid-liquid ratio of 1∶10 (m/V).Under the optimal conditions, the separation efficiency was over 91% and the relative PPO activity was 25.73%.The structure of fresh tea leaves changed insignificantly before and after the butane processing.This study suggested that the subcritical butane extraction technology could effectively remove pesticide residues in tea, thus provided a certain scientific basis for application of subcritical fluid removal of pesticide residue in natural plants.

Sublethal effect of Abamectin in the functional response of the predator Phytoseiulus persimilis (Athias-Henriot) on Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae)

Abstract The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.

Resumo O controle biológico utilizado para o controle de Tetranychus urticae (Koch) é o acaro predador Phytoseiulus persimilis (Athias-Henriot). É importante conhecer os efeitos dos acaricidas sobre o comportamento biológico do predador. Foi avaliado o efeito tóxico de a Abamectina na resposta funcional de P. persimilis. A resposta funcional do predador foi tipo II exposta a concentrações subletais de Abacmetina, os parâmetros da resposta funcional: taxa de ataque (a'), tempo de manipulação (Th), a eficiência na procura e predação teórica máxima (T/Th) foram afetados pelo acaricida. O predador passa mais tempo na procura, dominar, consumir e se preparar para a próxima procura em comparação com a testemunha e sua capacidade de predação foi afetada.

Simultaneous determination of abamectin homologs H 2 B 1a and H 2 B 1b in gel formulation by high performance liquid chromatography

ABSTRACT Abamectin is a drug with antiparasitic properties used in several pharmaceutical formulations. The objective of this research was to develop and validate a high performance liquid chromatographic (HPLC) method for quantification of the two abamectin homologs (H2B1a and H2B1b) in gel formulation. This HPLC method was validated using a LichroCart(r) 100 RP-18 (125 x 4 mm, 5 µm) column. The mobile phase contained of acetonitrile and water (95:5 v/v) with 1% acetic acid. The flow rate was 1.0 mL min-1 and UV detection was performed at 245 nm. Mobile phase solutions were prepared containing a nominal concentration 185.2 µg mL-1 H2B1a and 9.6 µg mL-1 H2B1b. The method displayed good linearity in the concentration range of 148.1 - 222.3 µg mL-1 and 7.7 - 11.5 µg mL-1, for H2B1a and H2B1b, respectively, with a correlation coefficient of (r)> 0.99 for both compounds, calculated by the least mean squares method. Detection limits (DLs) were 2.8 µg mL-1 and 1.2 µg mL-1 and quantitation limits (QLs) were 8.6 µg mL-1 and 3.8 µg mL-1, for H2B1a and H2B1b, respectively. The method is simple, economical and efficient for the quantitative determination of abamectin H2B1a and H2B1b homologs in pharmaceutical preparations.

Validação dos sistemas computadorizados empregados na determinação dos enantiômeros do nadolol e dos homólogos da ivermectina e da abamectina / Validation of the computer systems used in the determination of nadolol enantiomers and homologous of ivermectin and abamectin

O nadolol é um agente bloqueador de receptores ß-adrenérgicos empregado principalmente, na "angina pectoris", hipertensão, certas arritmias cardíacas e no tratamento do glaucoma (SING, 2006). A ivermectina e a abamectina são fármacos que apresentam ação antiparasitária (SHOOP, 1995). Na presente pesquisa, a cromatografia em fase líquida de alta eficiência foi uma das técnicas estudadas para a quantificação dos enantiômeros do nadolol e dos homólogos presentes na abamectina e ivermectina. A versatilidade desta técnica reside no grande número de fases estacionárias existentes, as quais possibilitam análises, separações e determinações quantitativas de uma ampla gama de compostos com alta eficiência (Aquino Neto e Nunes, 2003). Para identificação dos enantiômeros do nadolol foi utilizado o dicroísmo circular que permite a determinação da configuração absoluta de enantiômeros (LIMA, 1997). Para os enantiômeros do nadolol e dos homólogos presentes na abamectina e na ivermectina também foram realizados testes para desenvolvimento de uma metodologia de quantificação por meio de uma técnica relativamente recente chamada de eletroforese capilar (EC), a qual tem alcançado desde sua introdução um rápido desenvolvimento e ampla aplicação na análise de fármacos em medicamentos (SANTORO, 2000). Para a comprovação da qualidade e segurança dos sistemas computadorizados dos equipamentos de cromatografia em fase líquida de alta eficiência (CLAE) e de eletroforese capilar (EC) foram efetuadas, neste trabalho, as respectivas validações. Após esta validação, pode-se confirmar o correto funcionamento de um software, e suas interações com o hardware, onde devem ser levados em consideração, dentre outros, os aspectos relacionados à infra-estrutura, segurança e manutenção de dados (AGÊNCIA NACIONAL DE VIGILÂNIA SANITÁRIA, 2010). As metodologias analíticas desenvolvidas a para quantificação do nadolol, abamectina e ivermectina por cromatografia em fase líquida de alta eficiência foram validadas. A validação analítica deve garantir, por meio de estudos experimentais, que o método atenda às exigências das aplicações analíticas, assegurando a confiabilidade dos resultados. Para tanto, o método deve apresentar especificidade, linearidade, intervalo, precisão, sensibilidade, limite de quantificação e detecção, exatidão, adequados à análise (AGÊNCIA NACIONAL DE VIGILÂNCIA SANITÁRIA, 2003). Portanto, o objetivo proposto nesta pesquisa é primeiramente a validação dos sistemas computadorizados dos equipamentos de cromatografia em fase líquida de alta eficiência (CLAE) e de eletroforese capilar (EC). Para isto, serão desenvolvidos e validados os métodos analíticos de separação, identificação e quantificação dos enantiômeros do nadolol e dos homólogos presentes na abamectina e na ivermectina, em medicamentos, empregando as técnicas analíticas selecionadas

Nadolol is a blocking agent with activity in the ß -adrenergic receptors. It is mainly used in angina, hypertension, certain heart arrhythmias and in the treatment of glaucoma (SING, 2006). Ivermectin and abamectin are drugs with antiparasitic activity (SHOOP, 1995). In the present research, high performance liquid chromatography is one of the techniques used in the quantification of the enantiomers of nadolol and homologues present in abamectin and ivermectin. The versatility of this technique and the large number of existing stationary phases, enables the separation and quantitative determination of a wide range of compounds with high efficiency (Aquino Neto e Nunes, 2003). For identification of the nadolol enantiomers, circular dichroism was used which allows the determination of the absolute configuration of the enantiomers (LIMA, 1997). Nadolol enantiomers and the homologues present in abamectin and ivermectin will be also quantified by capillary zone electrophoresis (CE), a separation technique relatively recent, which has achieved, since its introduction, a wide application in the analysis of drugs in pharmaceutical preparations (SANTORO, 2000). In order to assure the quality of the analytical results, the computer systems of the liquid chromatograph and capillary electrophoresis equipments, must be validated prior to the analytical methods validation. Computer systems validation is used to verify and confirm the proper operation of softwares, and their interactions with the hardwares, besides the infrastructure, safety and storage of data (AGÊNCIA NACIONAL DE VIGILÂNIA SANITÁRIA, 2010). The analytical methodologies developed for quantification of nadolol, abamectin, ivermectin by using high efficiency liquid chromatography and capillary electrophoresis were validated. The analytical methods validation should ensure, through experimental studies, that the method meets the requirements for analytical applications, ensuring the reliability of the results. Parameters like, specificity, linearity, range, accuracy, sensitivity, limits of detection and quantification and accuracy, must be determined (AGÊNCIA NACIONAL DE VIGILÂNCIA SANITÁRIA, 2003). The objective of this study is to validate the computer systems of the high performance liquid chromatograph and capillary electrophoresis equipments and then to develop and validate analytical methods for separation, identification and quantification of nadolol enantiomers and the homologues of abamectin and ivermectin

Seed treatment affects Meloidogyne incognita penetration, colonization and reproduction on cotton / Tratamento de sementes afeta a penetração, colonização e reprodução de Meloidogyne incognita em algodão

The effect of abamectin, applied as seed treatment, on Meloidogyne incognita penetration, colonization, and reproduction on cotton was evaluated in two greenhouse experiments. Second stage juveniles (J2) penetration was evaluated 3, 9 and 15 days after germination (dag), whereas the nematode colonization was evaluated 27dag, by counting the total number of galls and egg masses per root system. Eggs and J2 were extracted from the roots to assess the nematode reproduction at 50 and 100dag. The seed treatment caused a decrease in J2 penetration in the roots, resulting in lower colonization and reproduction of M. incognita. These findings are discussed considering the environmental aspects of abamectin in the soil and the current practices for the crop management.

O efeito de abamectina em tratamento de sementes na penetração, colonização e reprodução de Meloidogyne incognita, em algodão, foi avaliado em dois experimentos de casa de vegetação. A penetração de juvenis de segundo estádio (J2) foi avaliada aos três, nove e 15 dias após a germinação (dag), enquanto que a colonização 27dag foi avaliada por meio da contagem do número total de galhas e massas de ovos por sistema radicular. Ovos e J2 de M. incognita foram extraídos das raízes para determinar a reprodução do nematoide aos 50 e 100dag. O tratamento de sementes diminuiu a penetração dos J2 nas raízes, resultando em menor colonização e reprodução de M. incognita. Os resultados obtidos são discutidos tendo em vista os aspectos ambientais da presença de abamectina no solo e as práticas agrícolas em uso.

Efecto de una nueva formulación de ivermectina + abamectina de larga duración contra nematodos gastrointestinales y la diferencia en ganancia de peso en bovinos / Effect of a new long life formulation of ivermectin + abamectin against gastrointestinal nematodes and the difference in weight gain in bovines

With the aim to evaluate the effect of ivermectin 2.25% + abamectin 1.25% in the reduction of gastrointestinal nematodes eggs per gram (epg) and the weight gain in bovines in 90 days, twenty four Santa Gertrudis breed, weaned calves localized in a ranch in Malpaso, Tecpatan municipality, Chiapas, Mexico, with a warm humid climate, were used. The calves were in extensive grazing on African Star and native grasslands. They were naturally infected with gastrointestinal nematodes (GIN), and were weighed on day -3. According to the individual weight and the egg count, two groups of 12 animals each, were integrated, without statistical difference in the weight and the average of epg, above of 700 eggs (P < 0.05). Group 1 was treated with one formulation of ivermectin at 2.25% + abamectina at 1.25%, in doses of 700 mcg/kg corresponding to 1 mL per 50 kg, by subcutaneous via. Group 2 was the control without anthelminthic treatment. Coprological examination was done at -3, 10, 45 and 90 days, moreover, coprocultures from each group were prepared with homogenized feces, in order to obtain larvae (L3). Weights were recorded on-3, and 45, 90 days after treatment. It was found that weight gain between Group 1, treated with 2.25% ivermectin + 1.25% abamectin, was 30.7 kg, equivalent to 350 g per day in average, with significant statistical difference (P < 0.05), in relation to the control group. The reduction percentage of epg showed difference at 10 and 45 days (P < 0.05), between the control and treated group; however, at 90 days they were not different. The genuses of GIN identified by frecuency order were: Haemonchus, Cooperia, Trichostrongylus, Oesophagostomum and Ostertagia.

Con el objetivo de evaluar el efecto de ivermectina 2.25% + abamectina 1.25% en la reducción de huevos de nematodos gastrointestinales por g de heces (hpgh) y la diferencia en la ganancia de peso en bovinos, se emplearon 24 becerros de la raza Santa Gertrudis, destetados, localizados en un rancho en Malpaso, municipio de Tecpatán, Chiapas, México, con clima cálido-húmedo. Los becerros estaban en pastoreo extensivo en potreros con pasto Estrella de África y gramas nativas. Dichos becerro, infectados con nematodos gastrointestinales (NGI) de manera natural, se pesaron el día -3 de acuerdo con los pesos individuales y las cuentas de hpgh, se conformaron dos grupos de 12 animales cada uno, sin que hubiera diferencia estadística en el peso ni en la media de hpgh, superior a 700 (P < 0.05). El Grupo1 fue tratado con una formulación de ivermectina a 2.25% + abamectina a 1.25%, en dosis de 700 mcg/kg equivalente a 1 mL por 50 kg, por vía subcutánea. El Grupo 2 fue el testigo, sin tratamiento antihelmíntico. Se realizaron exámenes coprológicos los días -3, 10, 45 y 90, además con homogeneizados de heces de cada grupo se prepararon coprocultivos para la cría de larvas (L3), el peso se registró el día -3, 45 y 90 después del tratamiento. Se encontró que la diferencia en la ganancia de peso en el G1 tratado con ivermectina 2.25% + abamectina 1.25%, fue de 30.7 kg, equivalente a 350 g por día en promedio, con diferencia estadísticamente significativa (P < 0.05) con el grupo testigo. En el porcentaje de reducción de hpgh hubo diferencia a los 10 y 45 días (P < 0.05) entre el testigo y el tratado; sin embargo, a los 90 días no la hubo. Los géneros de NGI identificados por orden de frecuencia fueron: Haemonchus, Cooperia, Trichostrongylus, Oesophagostomum, y Ostertagia.

Acute Toxic Effect of Abamectin on Fresh-water Aquatic Animals / 环境与健康杂志

Objective To discuss the acute toxicity of abamectin to several aquatic animals,it can provide reference for formulating safety concentration value of abamectin on fresh-water aquatic animals. Methods The method of changing solution was used for Cladocera crustacea with 48 h,and Allogynogenetic crucian carp fingerling (fry),Gambusia affinis,Hypophthal michthys molitrix fry,Macrobrachium nipponense,Eriocheir sinensis,Cipangopaludina chincasis with 96 h in this experiment. For the experimental animals,every kind of animal was randomly divided into 11 groups(495 animals in each),including nine treatment groups,one control group and one ethanol (hydrotropy agent) group (15 animals in each). The clinic symptoms were observed and mortalities were recorded;median-lethal concentration with 24,48,72,96 h and safety concentration were calculated. Results During the experiment,the mortalities of all animals increased with increase of time and concentration of abamectin. As for Cladocera crustacea,48 h LC50 and safety concentration were 0.000 37 and 0.000 037 mg/L,for Allogynogenetic crucian carp fry, Allogynogenetic crucian carp fingerling,Gambusia affinis,Hypophthal michthys molitrix fry,Macrobrachium nipponense, Eriocheir sinensis,Cipangopaludina chincasis,the values of 96 h LC50 were 0.018,0.06,0.08,0.02,0.52,0.25,0.57 mg/L and safety concentrations were 0.001 8,0.006,0.008,0.002,0.052,0.025,0.057 mg/L,respectively. The results showed that the toxicity of abamectin to seven fresh-water aquatic animals ranked as Cladocera crustacea,Allogynogenetic crucian carp fry,Hypophthal michthys molitrix fry,Allogynogenetic crucian carp fingerling,Gambusia affinis,Eriocheir sinensis,Macrobrachium nipponense, Cipangopaludina chincasis. Conclusion Abamectin has higher toxicity to fresh-water aquatic animals.