ABSTRACT Plant extracts are a great source of molecules with insecticidal activity and are used to control pests in various crop production systems. In this study, we evaluated the aphidicidal properties in vitro of the n-hexane extract of leaves of castor-bean (Ricinus communis L.; Euphorbiaceae) at different concentrations (0.5, 1.0, 2.5, 5.0 and 10 kg m-3) against apterous adults of corn leaf aphid (Rhopalosiphum maidis Fitch) and the yellow sugarcane aphid (Sipha flava Forbes). The observed effects were dose-dependent, and the highest concentration evaluated (10 kg m-3) caused 82% mortality in R. maidis and 79% in S. flava. To identify chemical compounds, present in the extract we used mass gas chromatography, identifying 16 compounds. Palmitic acid was the major compound, with 45.34% abundance. The data obtained indicate the existence of insecticidal compounds in the castor-bean n-hexane extract, which could be used as an alternative bioinsecticide in the integrated management of these two aphid species.

ABSTRACT The maize weevil (Sitophilus zeamais Motschulsky, 1855; Coleoptera, Curculionidae) is one of the most important pests associated with stored grains. It is controlled almost exclusively with synthetic insecticides. Thus, leading to problems such as pollution and resistance development. Hence an alternative is the use of natural compounds such as edible mushrooms derivates. The aim of this research was to assess, under laboratory conditions, the insecticidal and insectistatic effect of a hydroalcoholic extract of Pleurotus ostreatus (Jacq.) P. Kumm. 1871 against adults of S. zeamais. The parameters assessed were contact and fumigant toxicity, repellency, and antifeedant effect. The highest contact toxicity (57.5% mortality) was achieved with 30 mL extract L-1 solvent. No treatment showed repellent effect; the repellency index (RI) values were higher than 1, and the antifeeding activity < 30%. The fumigant effect showed a maximum of 30% mortality with the highest concentration (300 μL L-1 air). The hydroalcoholic extract of P. ostreatus exerts contact toxicity and interferes with insect reproduction or oviposition of Sitophilus zeamais.

ABSTRACT Agri-food production is affected by various factors, such as insect pests. Inadequate use of pesticides has generated resistance, and some pesticides have been shown to affect human health and the environment. Therefore, alternative control methods have been sought, such as the use of biocontrol with fungi; these organisms have shown activity against insect pests. Thus, this review compiles relevant and important studies that have been carried out over the last four decades. In general, fungi are divided into two large groups, macroscopic and microscopic fungi. In these two groups, possible fungal candidates with activity against insects have been found. They were subdivided into two groups: microscopic entomopathogenic fungi and macroscopic entomopathogenic fungi with basidiomata. In the case of microscopic entomopathogenic fungi, only the main species of these fungi (Metarhizium anisopliae, Beauveria bassiana, and Isaria fumosorosea) have been examined. These fungi present degrees of specificity at the family or closely related species level. For these three fungal species alone, more than 500 species of affected insects have been reported in this and other reviews. Finally, more than 200 species of fungi with basidiomata have been studied for their insecticidal activity. Additionally, possible compounds with insecticidal activity, such as ibotenic acid, beauvericin, ergosterol, and ostreolysin, are described. The studies found in the present review of fungi with insecticidal activity are promising. It was concluded that fungi, their compounds, and the proteins they contain may have a biotechnological application in the control of insect pests.

Abstract. Recently, the root-knot nematode Meloidogyne enterolobii have generated important economic losses (65%) in worldwide agriculture. In the present study, the nematocidal activity of the PdR-2 fraction of Pleurotus djamor was evaluated against the second instar juvenile (J2) of M. enterolobii. Different concentrations of the PdR-2 fraction (0.039, 0.078, 0.156, 0.132, 0.625, and 1.25 mg mL-1) were evaluated, as well as the respective control groups (water and Levamisole, 5 mg mL-1) in a volume of 100 µL (n=4). J2s were exposed for 24 h and subsequently quantified, and the percentage of mortality was estimated. Data were analyzed by analysis of variance with the general linear model and a comparison of means with Tukey’s test (p < 0.05). The PdR-2 fraction at concentrations of 0.132, 0.625, and 1.25 mg mL-1 were significantly equal with respect to Levamisole application, showing a mortality of 87.6, 84.5, and 86.3%, respectively. At the lowest concentration (0.039 mg mL-1), 40.3% mortality was recorded, whereas 86% was recorded at the highest concentration evaluated (1.25 mg mL-1). The PdR-2 fraction of P. djamor had nematocidal activity against J2s of M. enterolobii.

Resumen. Recientemente, el nematodo agallador Meloidogyne enterolobii ha generado importantes pérdidas económicas (65%) en la agricultura a nivel mundial. En el presente estudio se evaluó la actividad nematicida de la fracción PdR-2 de Pleurotus djamor contra juveniles del segundo estadio (J2) de M. enterolobii. Se evaluaron diferentes concentraciones de la fracción PdR-2 (0.039, 0.078, 0.156, 0.132, 0.625 y 1.25 mg mL-1), así como los respectivos grupos de control (agua y Levamisol, 5 mg mL-1) en un volumen de 100 µL (n=4). Los J2 fueron expuestos durante 24 h y posteriormente cuantificados, y se estimó el porcentaje de mortalidad. Los datos se analizaron mediante un análisis de varianza y una comparación de medias con la prueba de Tukey (p<0,05). La fracción PdR-2 a concentraciones de 0.132, 0.625 y 1.25 mg mL-1 fue significativamente igual con respecto a la aplicación de Levamisol, con una mortalidad de 87.6, 84.5 y 86.3%, respectivamente. En la concentración más baja (0.039 mg mL-1) se registró una mortalidad del 40.3%, mientras que en la concentración más alta (1.25 mg mL-1) se registró un 86%. La fracción PdR-2 de P. djamor tuvo actividad nematicida contra los J2 de M. enterolobii.

ABSTRACT Alternative methods of control against different parasites affecting livestock and agriculture are currently being sought. The essential oil of Peumus boldus Molina has anthelmintic and insecticidal activity against the nematode Haemonchus contortus and stored cereal insect pests. The present study aimed to assess the in vitro activity of P. boldus essential oil against H. contortus (L3) unsheathed and Sitophilus zeamais, Tribolium castaneum, and Plodia interpunctella. The essential oil was obtained from leaves of P. boldus and its principal compounds identified by phytochemical analysis. Essential oil was tested at concentrations of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2.0 mg mL-1 on unsheathed L3 H. contortus larvae and in concentrations of 0, 35, 70, 100, 125, 150, 175 and 200 μL L-1 air on adult insects. The main constituents detected in the essential oil were 1,8-cineole, terpineol, terpinene-4-ol, γ-terpinene, p-cimene, methyl eugenol, safrole, (E)-germacrene D, β-tujene, and ascaridol. The nematode H. contortus and insects were exposed to the essential oil for 72 h. In a bioassay with H. contortus larvae, treatment with 2.0 mg mL-1 showed the highest toxicity with 99.2% mortality. Regarding insecticidal activity, S. zeamais was the most susceptible species with a mortality of 90% at 200 μL L-1 air. The present study suggests that the essential oil of P. boldus has potential anthelmintic and insecticidal activity.

Abstract The present study aimed to evaluate, in vitro, the cestocidal effect of Pyrantel-Oxantel on the Dipylidium caninum tapeworm. Each intestine sample was obtained by means of a transversal incision of the abdominal area of each euthanized canine subject, individually dissected via longitudinal incision, and examined for the presence of D. caninum. An optical microscope was used to identify and verify proglottid morphology and viability based on its macroscopic appearance. The cestocidal effects of Pyrantel-Oxantel (75 mg pyrantel pamoate; 75 mg oxantel pamoate) were assessed in adult tapeworms (treated group, n= 21; control group, n= 21) placed on Petri dishes and incubated at 37 °C. One-hour post-incubation, the D. caninum cestodes treated with Pyrantel-Oxantel presented a 28 % decrease (P=0.001) in motility, which rose to a 52 % (P=0.0001) decrease by the end of the second hour. The control group (P=0.0001) presented 55.7 % motility for at least the first six hours of incubation and 4.2 % (P=0.001) motility by the end of the study, while 0 % motility was observed in the treated group by the end of the study. Pyrantel-Oxantel had a lethal effect (P=0.0001) on adult D. caninum, with 100 % mortality observed 6 h after in vitro post-incubation, while the control group presented 55.7 % viability after the same time period. In addition, Pyrantel-Oxantel reduced (P=0.001) tegument thickness by 42.5 % (10.24 ± 0.21 µm), while this was 17.81 ± 0.33 µm for the control group. The results of this study indicate that Pyrantel-Oxantel has a therapeutic effect on the presence of D. caninum, inducing both a reduction of the tegument thickness and increased mortality.

Resumen El presente estudio tuvo como objetivo evaluar, in vitro, el efecto cestocida de Pirantel-Oxantel en la tenia Dipylidium caninum. Cada muestra de intestino se obtuvo mediante una incisión transversal de la zona abdominal de cada sujeto canino sacrificado, se diseccionó individualmente a través de una incisión longitudinal y se examinó para detectar la presencia de D. caninum. Se utilizó un microscopio óptico para identificar y verificar la morfología y viabilidad de la proglótide en función de su aspecto macroscópico. Los efectos cestocidas de Pirantel-Oxantel (75 mg de pamoato de pirantel; 75 mg de pamoato de oxantel) se evaluaron en tenias adultas (grupo tratado, n= 21; grupo testigo, n= 21) colocadas en placas de Petri e incubadas a 37 °C. Una hora postincubación, los cestodos D. caninum tratados con Pirantel-Oxantel presentaron una disminución del 28 % (P= 0.001) en la motilidad, la cual aumentó a una disminución del 52 % (P=0.0001) al final de la segunda hora. El grupo testigo (P= 0.0001) presentó un 55.7 % de motilidad durante al menos las primeras 6 h de incubación y 4.2 % (P= 0.001) de motilidad al final del estudio, mientras que en el grupo tratado se observó un 0 % de motilidad al final del estudio. El Pirantel-Oxantel tuvo un efecto letal (P= 0.0001) en el adulto de D. caninum, con una mortalidad del 100 % observada 6 h después de la postincubación in vitro, mientras que el grupo de control presentó un 55.7 % de viabilidad después del mismo periodo. Además, el Pirantel-Oxantel redujo (P= 0.001) el grosor del tegumento en 42.5 % (10.24 ± 0.21 μm), mientras que éste fue de 17.81 ± 0.33 μm para el grupo testigo. Los resultados de este estudio indican que el Pirantel-Oxantel tiene un efecto terapéutico en la presencia de D. caninum, induciendo tanto una disminución del grosor del tegumento como un aumento de la mortalidad.

ABSTRACT Insect pests of stored cereals cause losses between 10 and 20%, which requires the search for effective and environmentally friendly control alternatives that pose no threat to human health. The objective of this study was to evaluate under laboratory conditions the insecticidal and insectistatic activity of Eucalyptus globulus and Eucalyptus nitens foliage powder against Sitophilus zeamais. The studied variables were contact and fumigant toxicity and repellent and anti-feed activity. The contact and fumigant toxicity did not exceed 40% mortality in any of the concentrations evaluated, although the concentration of 8.0% affected the progeny, recording 80.9% inhibition of adult insect emergence (F1) in E. globulus and 86.7% inhibition in E. nitens. All the treatments showed repellency and E. nitens recorded a feeding deterrence index (FDI) of 60.5%. It can be concluded that E. globulus and E.nitens powder has potential as a repellent and inhibitor of the life cycle of S. zeamais.

RESUMEN Los insectos plaga de los cereales almacenados causan pérdidas entre 10 y 20%, lo que hace necesaria la búsqueda de alternativas de control efectivas, amigables con el medio ambiente y que no representen riegos para la salud de las personas. El objetivo de la presente investigación fue evaluar, en condiciones de laboratorio, la acción insecticida e insectistática del polvo de follaje de Eucalyptus globulus y Eucalyptus nitens para el control de Sitophilus zeamais. Las variables estudiadas fueron toxicidad por contacto y fumigación y actividad repelente y anti-alimentaria. La toxicidad por contacto y fumigación no superó el 40% de mortalidad en ninguna de las concentraciones evaluadas, aunque el tratamiento de 8,0% afectó la progenie, registrando un 80,9% de inhibición de la emergencia de insectos adultos (F1) para E. globulus y de 86,7% en E. nitens. La totalidad de los tratamientos mostró efecto repelente y el polvo de E. nitens presentó un índice de disuasión de la alimentación (IDA) de 60,5%. Se concluye que el polvo de follaje de E. globulus y E.nitens presenta potencial como repelente e inhibidor del ciclo de S. zeamais.

Abstract Background: Edible mushrooms have nutraceutical properties, mainly in humans, animals and plants. Pleurotus species represent an alternative approach to parasite control because they have nematicidal activity against different taxonomic genera of nematodes of importance for livestock. Objective: To present a general overview of fungi of the genus Pleurotus and their characteristics as a sustainable method of biocontrol for parasitic nematodes of animals with importance in public health. Methods: This bibliographic review was carried out by consulting published studies on edible fungi of the genus Pleurotus and analyzing their properties related to nematicidal activity. The works were grouped according to their research focus; works related to keywords and topics in livestock were identified in indexed journals and on digital platforms (academic Google). Results and conclusions: Pleurotus spp. produce different secondary metabolites with antiparasitic activities, mainly anthelmintic and particularly against gastrointestinal nematodes and their larval stages. The characteristics of these fungi are excellent for biotechnological applications since they produce a wide range of secondary metabolites in different parts, such as in the basidiomata, mycelia and degraded substrates. There are new lines of research that must be addressed to demonstrate their effectiveness in the area of biocontrol in livestock.

Resumen Antecedentes: Los hongos comestibles presentan propiedades nutracéuticas principalmente para los humanos, animales y plantas. Las especies de Pleurotus representan una alternativa de control de parásitos ya que tienen actividad nematicida contra diferentes géneros taxonómicos de nematodos de importancia pecuaria. Objetivo: Presentar un panorama general sobre los hongos del género Pleurotus y sus características como método sustentable de biocontrol de nematodos parásitos de animales de importancia en salud pública. Métodos: La revisión bibliográfica se llevó a cabo consultando estudios publicados sobre el género del hongo Pleurotus y sus propiedades, analizando lo referente a la actividad nematicida. Los trabajos fueron agrupados de acuerdo con su enfoque de investigación de trabajos en revistas indexadas y en la plataforma (Google academico), digital relacionada con palabras clave y temas del área pecuaria. Resultados y conclusiones: Pleurotus spp. cuenta con diferentes metabolitos secundarios con actividad antiparasitaria principalmente antihelmíntica y particularmente contra nematodos gastrointestinales. Las características que tiene este hongo son excelentes para sus aplicaciones biotecnológicas ya que presenta una amplia gama de metabolitos secundarios en diferentes partes como son los basidiomas, el micelio y el sustrato degradado. Existen nuevas líneas de investigación que se deberán atender para demostrar su eficacia en biocontrol en el área pecuaria.

Abstract Background: Pleurotus is one of the best-known edible mushroom genera. In recent years there has been a marked interest in its commercial production, which has led to the search for substrates or mixtures that ensure high productivity. Objective: To determine the effect of the main chemical components of substrates for the production of two strains of Pleurotus spp. Methods: Different mixtures were made from corn cob, grass and coffee pulp, establishing 10 treatments, which were bromatologically analyzed. Two strains of Pleurotus spp. were cultivated. The Biological Efficiency (BE), Production Rate (TP) and Yield (R) were evaluated. Results and conclusions: In both strains ECS-123 and ECS-1123, treatment 7 (100 % grass) obtained the highest values of EB (38.2 % and 48.8 %, respectively), TP (0.5 % and 0.6 %, respectively) and R (14.7 and 18.8 %, respectively). These values were not statistically different from other treatments containing grass, but from the one with higher nitrogen content (coffee pulp) so it is stated that a nitrogen concentration of 0.5 % and C/N ratio of 96.75 are sufficient to obtain a good production of basidiomata. The importance of other factors on the production of strains is highlighted.

Resumen Antecedentes: En los últimos años se ha presentado un marcado interés por la producción comercial de Pleurotus spp., lo cual ha ocasionado la búsqueda de sustratos o mezclas que aseguren una alta productividad. Objetivos: Determinar el efecto de los principales componentes químicos del sustrato en la producción de basidiomas de dos cepas del género Pleurotus. Métodos: A partir de olote, pasto y pulpa de café se prepararon 10 tratamientos, que fueron analizados bromatológicamente. Se cultivaron dos cepas de Pleurotus spp. y se evaluó la eficiencia biológica (EB), la tasa de producción (TP) y el rendimiento (R). Resultados y conclusiones: En ambas cepas cultivadas, ECS-123 y ECS-1123, el tratamiento 7 (100 % pasto) obtuvo los valores más altos de EB (38.2 % y 48.8 %, respectivamente), TP (0.5 % y 0.6 %, respectivamente) y R (14.7 y 18.8 %, respectivamente). Estos valores no fueron estadísticamente diferentes de otros tratamientos con pasto, pero sí de la pulpa de café (con mayor contenido de nitrógeno). Se concluye que es suficiente una concentración de nitrógeno de 0.5 % y una relación C/N de 96.75 para obtener una buena producción de basidiomas. Se resalta la incidencia de otros factores en la productividad de las cepas.

ABSTRACT Sitophilus zeamais is one of the major pests of stored cereals worldwide and its control is based on the use of synthetic insecticides, but their irrational use has caused environmental pollution and resistance. Essential oils have shown contact and fumigant insecticidal effect and could be an alternative to synthetic compounds. Hence, the insecticidal properties of essential oil of Chenopodium ambrosioides L. were assessed under laboratory conditions against adults of Sitophilus. zeamais. The variables studied were contact and fumigant toxicity, and antifeedant and repellent activity. Mortality by contact toxicity did not exceed 30% in all the treatments evaluated. The highest F1 reduction was observed in the treatment of 4.0% with 41.3% of emergence (58.7% of inhibition). Grain weight loss was lower than 9.0% and maize germination was not affected. All treatments exhibited fumigant activity, while concentrations equal to or lower than 0.5% showed repellent and feeding deterrent effect. It can be concluded that essential oil of Ch. ambrosioides has potential for S. zeamais control.

RESUMEN Sitophilus zeamais Motschulsky es a nivel mundial una de las principales plagas de los cereales almacenados y su control se basa en insecticidas sintéticos, pero su uso irracional ha provocado contaminación del ambiente y resistencia. Los aceites esenciales han mostrado efecto insecticida de contacto y fumigante por lo que podrían constituir una alternativa a los compuestos sintéticos. Por este motivo se evaluaron, en condiciones de laboratorio, las propiedades insecticidas del aceite esencial de Chenopodium ambrosioides L. contra adultos de S. zeamais. Las variables evaluadas fueron toxicidad por contacto y fumigación, y actividad antialimentaria y repelente. La mortalidad por contacto no superó el 30% en todos los tratamientos evaluados. La mayor reducción de la F1 se observó en el tratamiento de 4,0% con 41,3% de emergencia (58,7% de inhibición). La pérdida de peso de los granos fue menor a 9,0% y la germinación del maíz no se vio afectada. Todos los tratamientos mostraron actividad fumigante y las concentraciones iguales o superiores a 0,5% tuvieron efecto repelente y antialimentario. Se concluye que el aceite esencial de Ch. ambrosioides presenta potencial para el control de S. zeamais.

ABSTRACT The maize weevil, Sitophilus zeamais Motschulsky, is one of the most important pests of stored cereals worldwide. Currently, it is mainly controlled with the use of synthetic insecticides, with poor variation of action mechanisms. Natural compounds, particularly plant extracts, are an alternative to control this pest. The objective of this study was to evaluate, under laboratory conditions, the insecticidal/insectistatic effect of extracts with different polarity solvents of Pleurotus ostreatus Kumm against S. zeamais adult. The variables evaluated were contact and fumigant toxicity, repellency and antixenosis. A completely randomized experimental design was used. The highest toxicity was obtained by fumigation with ethyl acetate extract with a mortality of 100% at a concentration of 30 µL 0.15 L-1 air, and a CL50 of 18,3 µL at 0,15 L-1 air. Extracts in ethyl acetate and distilled water showed repellent activity, while all extracts exhibited antixenosis effects. It can be concluded that P. ostreatus extract in ethyl acetate has fumigant, repellent and antixenotic activity against S. zeamais adult.

RESUMEN El gorgojo del maíz, Sitophilus zeamais Motschulsky, es a nivel mundial una de las plagas más importantes de los cereales almacenados. Actualmente su manejo se realiza principalmente con insecticidas sintéticos, con escasa variación de mecanismos de acción, por lo que una alternativa son los compuestos naturales, especialmente los extractos vegetales. El objetivo de esta investigación fue evaluar, en condiciones de laboratorio, el efecto insecticida/insectistático de extractos de Pleurotus ostreatus Kumm con solventes de distinta polaridad para el control de adultos de S. zeamais. Las variables evaluadas fueron toxicidad por contacto y fumigación, repelencia y antixenosis, con un diseño experimental completamente al azar. La mayor toxicidad se obtuvo por fumigación con el extracto en acetato de etilo con una mortalidad de 100% en la concentración 30 µL en 0,15 L-1 aire y una CL50 de 18,3 µL en 0,15 L-1 aire. Los extractos en acetato de etilo y agua destilada mostraron actividad repelente y todos registraron efecto de antixenosis. Se concluyó que el extracto de P. ostreatus en acetato de etilo presenta actividad fumigante, repelente y antixenótica sobre adultos de S. zeamais.

Resumo Fungos nematófagos das fezes de búfalo de água e do solo no sudeste do México foram isolados, e a atividade predatória in vitro contra larvas infectantes de Haemonchus contortus (L3) (HcL3) foi avaliada.Os fungos foram isolados por aspersão de solo e de fezes em placas de agar água. Foram preparadas seis séries de 10 placas de Petri contendo uma cultura de 7 dias de idade de cada fungo e uma série sem fungos como controle. Quinhentos HcL3 foram adicionadas a cada placa. As placas foram incubadas à temperatura ambiente. O número médio de HcL3 recuperadas foi considerado para estimar a taxa de redução larval. Quatro isolados de fungos nematófagos corresponderam a Arthrobotrys oligospora, var microspora (estirpes 4-276, 269 e 50-80) e um isolado identificado como A. oligospora, var. oligospora (isolados 48-80 de fezes de búfalo de água. Do solo, dos cinco isolados três corresponderam a A. musiformis (Bajío, Yumca e Macuspana isolados), e dois isolados foram identificados como A. oligospora (isolados de Comalcalco e Jalapa de Méndez). A atividade predatória de isolados de fezes de búfalo de água variou entre 85,9 e 100%. Enquanto isso, os fungos do solo variaram entre 55,5 e 100% (p≤0,05). Os fungos nematófagos obtidos podem ter importantes implicações nesse controle de parasitos de importância na indústria pecuária.

Abstract Nematophagous fungi from the feces of water buffalo and soil from southeastern Mexico were isolated, and their in vitro predatory activity against Haemonchus contortus infective larvae (L3) (HcL3) was assessed. The fungi were isolated by sprinkling soil or feces on water agar plates. Six series of 10 Petri dishes containing a 7-day-old culture of each fungus and a series without fungi as the control were prepared. Five hundred HcL3 were added to each plate. The plates were incubated at room temperature. The average of recovered HcL3 was considered to estimate the larval reduction rate. Four nematophagous fungi isolates corresponding to Arthrobotrys oligospora, var microspora (strains 4-276, 269 and 50-80) and one identified as A. oligospora,var. oligospora (isolates 48-80) were obtained from water buffalo feces. From the soil, five isolates were isolated; three corresponded to A. musiformis (Bajío, Yumca and Macuspana isolates), and two isolates were identified as A. oligospora (Comalcalco and Jalapa de Méndez isolates). The predatory activity of isolates from water buffalo feces ranged between 85.9 and 100%. Meanwhile, the fungi from the soil ranged between 55.5 and 100% (p≤0.05). The nematophagous fungi obtained could have important implications in the control of parasites of importance in the livestock industry.

Resumen Antecedentes: La identificación del fenotipo relacionado con la resistencia contra nematodos gastrointestinales (GIN) es necesaria para conocer la inmunidad del huésped en ovejas en producción. Objetivo: Determinar los parámetros hematológicos e inmunológicos (IgA e IgG) en gestación y lactancia en ovejas Blackbelly infectadas naturalmente con GIN. Métodos: Se determinó el número de huevos por gramo de heces (EPG), se identificaron las larvas y se registró el porcentaje del volumen celular aglomerado (% PCV), proteína plasmática (PP) y eosinófilos periféricos durante ocho meses. Además, se colectó suero y saliva para determinar la cinética de IgG e IgA por medio de un ensayo inmuno-enzimático (ELISA) indirecto. Resultados: Los resultados mostraron 2.592 ± 2.403 EPG y 22,2 ± 4,0% PCV durante la lactancia y 595 ± 901 EPG y 25,1 ± 2,5% PCV durante la gestación. Se observó un mayor porcentaje de larvas de Trichostrongylus colubriformis en gestación (84 a 100%) que en lactancia (36 a 44%). La actividad de la IgA en las muestras de suero mostró una marcada reducción después del parto para ambos antígenos de Haemonchus contortus y T. colubriformis (80 a 10%). En saliva, la actividad de la IgA disminuyó de 56 a 30% del día 60 al 45 antes del parto y se mantuvo baja en los primeros 45 días de la lactancia (actividad de 23 a 32%). El número de eosinófilos fue de 2,0 x 109 células L-1 durante la gestación, y se redujo a 0,7 x 109 células L-1 en la lactancia. Conclusión: Las variables estudiadas reflejan la ruptura de la inmunidad contra GIN en ovejas Blackbelly antes y después del parto.

Abstract Background: It is necessary to identify phenotypic traits related to natural resistance against gastrointestinal nematodes (GIN) in order to know the host immunity status in productive ewes. Objetive: To determine haematological and immunological parameters (IgA and IgG) during pregnancy and lactation in Blackbelly ewes naturally infected with GIN Methods: The number of eggs per gram (EPG), packed cell volume (% PCV), plasmatic protein (PP), and peripheral eosinophils were determined during eight months. In addition, sera and saliva samples were collected to establish IgG and IgA kinetics by indirect enzyme-linked immunosorbent assay (ELISA). Results: The results showed 2,592 ± 2,403 EPG and 22.2 ± 4.0% PCV during lactation and 595 ± 901 EPG and 25.1 ± 2.5% PCV during pregnancy. A higher percentage of Trichostrongylus colubriformis larvae were observed in pregnancy (84 to100%) than in lactation (36 to 44%). The IgA activity in serum samples showed a marked reduction (from 80 to 10%) during lambing for both Haemonchus contortus and T. colubriformis antigens. In saliva samples, IgA activity with regard to the standard decreased from 56% at 60 days to 30% at 45 days before lambing and remained low for 45 days during lactation (23 to 32% activity). The eosinophils numbers were 2.0 x 109 cells L-1 in pregnancy and remained low at 0.7 x 109 cells L-1 in lactation. Conclusion: The studied variables reflect the breakdown of immunity against GIN in Blackbelly ewes before and after lambing.

Resumo Antecedentes: A identificação de traços fenotípicos relacionados à resistência natural contra nematóides gastrintestinais (GIN) é necessária para saber a imunidade do hospedeiro em ovelhas produtivas. Objetivo: Determinar parâmetros hematológicos e imunológicos (IgA e IgG) em períodos de gestação e lactação em ovelhas Blackbelly naturalmente infectados com GIN. Métodos: O número de ovos por grama (EPG), volume empacotado de células (% PCV), proteína plasmática (PP) e eosinófilos periféricos foram determinados durante oito meses. Além disso, as amostras de soro e saliva foram recolhidas para determinar a cinética de IgG e IgA por ELISA indireto. Resultados: Os resultados mostraram 2.592 ± 2.403 EPG e 22,2 ± 4,0% PCV durante a lactação e 595 ± 901 EPG e 25,1 ± 2,5% PCV durante a gravidez. A percentagem mais elevada de larvas de Trichostrongylus colubriformis foi observada na gravidez (84 a 100%) do que na lactação (36 a 44%). A atividade de IgA em amostras de soro mostrou uma redução acentuada (80 a 10%) durante o parto nos antígenos de Haemonchus contortus e T. colubriformis. Em amostras de saliva, a atividade de IgA diminuiu de 56 a 30% do dia 60 ao 45 antes do parto e permaneceu baixa por 45 dias durante a lactação (atividade de 23 a 32%). O número de eosinófilos foi de 2,0 x 109 células L-1 na gravidez e manteve-se baixo, com 0,7 x 109 células L-1 na lactação. Conclusaõ: As variáveis estudadas refletem a quebra da imunidade contra GIN em ovelhas Blackbelly antes e depois do parto.

The aim of this study was to evaluate the predatory behavior in vitro of the mite Lasioseius penicilliger on 3 nematode species: Teladorsagia circumcincta (L3) (a sheep-parasitic nematode), Meloidogyne sp. (J2) (a plant-parasitic nematode), and on various developmental stages of Caenorhabditis elegans (a free-living nematode). The coincubation of mites and nematodes was individually assessed in 2% water agar placed in plastic Petri dishes (2 cm x 1 cm diameter). One thousand nematodes of a species and 5 mites were placed into each plate (10 replicates) and incubated for 5 days at room temperature (18-25ºC). L. penicilliger showed predatory behavior against the 3 assessed nematode species. The percentages of predatory activity recorded were 95.1, 80.5 and 79.3 against Meloidogyne sp., C. elegans, and T. circumcincta, respectively (P ≤ 0.05). These results suggest that L. penicilliger has important potential as a biological control agent of parasitic nematodes.

El objetivo de este estudio fue evaluar el comportamiento depredador in vitro del ácaro Lasioseius penicilliger sobre tres especies de nemátodos: Teladorsagia circumcincta (L3, nemátodo parásito de ovejas), Meloidogyne sp. (J2, nemátodo parásito de plantas), y sobre varios estadios de desarrollo de Caenorhabditis elegans (nemátodo de vida libre). La coincubación de los ácaros y los nemátodos se evaluó en 2% agar-agua colocados en cajas de Petri de plástico (2 cm x 1 cm diámetro). Se colocaron 1 000 nemátodos de cada especie y cinco ácaros en cada caja (10 réplicas) y se incubaron por cinco días a temperatura ambiente (18-25ºC). L. penicilliger mostró comportamiento depredador contra las tres especies de nemátodos evaluadas. Los porcentajes de actividad depredadora registrados fueron 95.1, 80.5 y 79.3, contra Meloidogyne sp., C. elegans y T. circumcincta, respectivamente (P ≤ 0.05). Estos resultados sugieren que L. penicilliger tiene un importante potencial como agente de control biológico contra nemátodos parásitos.

Bacillus thuringiensis is an entomopathogenic bacterium that produces crystal-proteins with cytotoxic activity against insects and nematodes. B. thuringiensis toxicity on agriculture pests is widely recognized; however, there is little information about the lethal action of B. thuringiensis against nematodes. Recently, the nematicide activity of B. thuringiensis proteins was showed against Haemonchus, Teladorsagia, Nippostrongylus, and Ancylostoma genera of mammals, and against the plant parasitic nematodes, Globodera and Meloidogyne. From a list of B. thuringiensis strains with nematicide effect, selected proteins from the IB-16 isolate showed 50 to 100 % nematocidal efficacy against different developing stages of H. contortus. Additionally the in vitro assay showed evidence about the lethal activity of this strain against the free-living nematodes Panagrellus redivivus and Caenorhabditis elegans. The Cry5B protein of B. thuringiesis caused tissue damage on the C. elegans mid-gut and its action probably involves specific gut-receptor, similar to reporte with nematodes of importance in agriculture. Also, Cry5B protein-receptors link appears to involve carbohydrate moieties on intestinal cells, and cause tissue damage and nematodes death. Through these studies, selected B. thuringiensis proteins could be considered in future trials as potential alternative tools of control against parasitic nematodes of domestic animals, such as ruminants and other pathogens of mammals and even from agriculture crops.

La bacteria entomopatógena Bacillus thuringiensis produce cristales proteicos con actividad citotóxica en contra de insectos y nematodos. La toxicidad de B. thuringiensis en plagas agrícolas es ampliamente conocida, pero poco se conoce acerca de su actividad en contra de nematodos parásitos. Recientemente, la actividad nematicida de las proteínas derivadas de B. thuringiensis se demostró en parásitos de mamíferos como Haemonchus, Teladorsagia, Nippostrongylus, y Ancylostoma, y en nematodos de plantas, Globodera y Meloidogyne. Entre el grupo de B. thuringiensis con efecto nematicida, las proteínas de la cepa IB-16 han mostrado actividad letal de 50 a 100 % en contra de diferentes estadios del principal género de rumiantes, Haemonchus contortus. Asimismo, los géneros de nematodos de vida libre, Panagrellus redivivus y Caenorhabditis elegans han sido blanco de estudios de la acción nematicida de B. thuringiensis. Por ejemplo, el efecto tóxico de la proteína Cry5B de B. thuringiensis se observó en las células intestinales de C. elegans, además esta acción parece involucrar receptores celulares específicos, similares a los que se han notificado en contra de plagas agrícolas. Asimismo, la unión de la proteína Cry5B ocurre en receptores específicos, como moléculas de carbohidratos, las cuales están presentes en la membrana de las células de intestino de los nematodos, ocasionando daño y muerte. A través de este tipo de estudios, los derivados de B. thuringiensis podrían considerarse una alternativa de control en nematodos que afectan a los animales domésticos, como rumiantes, así como en contra de otros nematodos patógenos de mamíferos e incluso de plantas agrícolas.