Metarhizium anisopliae has been considered a promising alternative with low environmental impacts for the biological control of a variety of insect-pests. Another alternative is the use of biological pesticides such as insect growth regulators, including lufenuron. An assessment of the potential impact of fungicides on M. anisopliae is of critical importance to integrated pest management, permitting the compatible use of this entomopathogen with chemical defensives. Based on this, this study aimed to evaluate the effect of different concentrations of lufenuron on the conidia germination speed of M. anisopliae. Conidia were incubated at 28°C and sampled throughout 12 h. Bayesian analysis showed an inhibition of conidia germination in the presence of 2.0 mg/ml of lufenuron, whereas their compatibility was observed in the concentrations of 1.0 mg/ml and 700 µg/ml. It indicates that in these last two concentrations, the fungicide has no toxicity on M. anisopliae, what suggests that it can be employed in biological-chemical combinations, maintaining viable the fungal inoculums after its application in the field, with a low environmental impact.
SUMMARYThe aim of this study was to evaluate the supplementation of ethanolic extract of propolis (EEP) in broiler chickens diets on immune responses (humoral and cellular), weight of lymphoid organs and hematological profile. A total of 192 birds, raised in metabolism cages until the 21st day, were distributed in a completely randomised design with six treatments, eight replicates and four birds per experimental unit. The treatments consisted of diets containing 0; 1,000; 2,000; 3,000; 4,000 and 5,000 ppm of EEP. The inclusion of EEP gave a quadratic effect (P < 0.05) for relative weight of spleen and cloacal bursa, with the lowest weights found at the level of 2,946 ppm and 2,985 ppm of EEP, respectively. For the relative weight of thymus no change was observed (P > 0.05). There was no change (P > 0.05) in percentages of lymphocyte, heterophil, basophil, eosinophil and heterophil: lymphocyte ratio with the inclusion of EEP. However, there was a reduction (P < 0.05) in the percentage of monocyte to the inclusion level of 3,000 ppm of EEP when compared to control. The phagocytic activity of macrophages, the average number of phagocytised red cells and nitric oxide production were not affected (P > 0.05). The interdigital response to phytohaemagglutinin showed negative linear and quadratic behavior (P < 0.05) as a function of time and levels of inclusion, respectively, noting the smallest value of the reaction with 3,074 ppm of EEP. The birds showed a linear increase (P < 0.05) of serum antibodies against Newcastle disease, however, when each level of inclusion was compared to the control no difference was observed (P > 0.05). It is concluded that the addition of 1,000 to 5,000 ppm of EEP to the starter broiler diet did not have immunostimulant effect.Key words: antibody, cellular immune response, immune system, humoral immune response. RESUMENEste estudio evaluó la suplementación de extracto etanólico de propóleos (EEP) en dietas de pollos de engorde sobre la respuesta inmune (humoral y celular), peso de órganos linfoides y perfil hematológico. Se utilizaron 192 pollos de engorde, machos, criados en jaulas de metabolismo hasta los 21 días de edad. El diseño experimental fue completamente al azar con seis tratamientos, que consistieron en diferentes niveles de inclusión de EEP (0; 1.000; 2.000; 3.000; 4.000 y 5.000 ppm), con ocho repeticiones y cuatro aves por unidad experimental. La inclusión dietética de EEP provocó un efecto cuadrático (P < 0,05) en el peso relativo del bazo y bolsa de Fabricio, con menores pesos en pollos suplementados con 2.946 y 2.985 ppm de EEP, respectivamente. En el peso relativo del timo no se observó efecto (P > 0,05) de los tratamientos. La inclusión de EEP no alteró (P > 0,05) el porcentaje de linfocitos, heterófilos, basófilos, eosinófilos y la relación heterófilo:linfocito. Hubo reducción (P < 0,05) en el porcentaje de monocitos con la inclusión de 3.000 ppm de EEP en comparación al control. La actividad fagocítica de los macrófagos, número promedio de eritrocitos fagocitados y pro...
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