Ecotoxicological effects of fipronil, neem cake and neem extract in edaphic organisms from tropical soil.

Veterinary medicines are widely applied for the treatment and prevention of animal diseases. Consequently, animal manure contains significant amounts of environmental pollutants that are potential sources of environmental pollution when inappropriately applied in soils. This work aimed to evaluate ecotoxicological effects of doses of commercial fipronil, neem cake and neem extract in the survival and reproduction of earthworms (Eisenia andrei), enchytraeidae (Enchytraeus crypticus) and springtails (Folsomia candida) in Oxisol and tropical artificial soil (TAS). Applications of fipronil, neem cake and extract in soil were carried out according to standardized ISO methodologies by using a random experimental design with five replicates. Toxic effects of fipronil for springtails in Oxisol and TAS were observed with LC50 of 0.26 mg kg-1 (0.18-0.35 mg kg-1) and 0.29 mg kg-1 (0.22-0.37 mg kg-1), respectively. It was not observed significant toxic effects of fipronil for earthworms and enchytraeidae in both soils. However, significant amounts of juvenile earthworm and adult enchytraeidae decreased in fipronil doses higher than 10 mg kg-1. Neem cake and extract were not toxic for earthworms and enchytraeidae but, significant amounts of juvenile springtails decreased in neem cake doses from 500 to 1000 mg kg-1. It can be concluded that the use of veterinary medicines containing synthetic compounds for preventing diseases in animals needs to be controlled to avoid environmental pollution after applying manure in soil. Veterinary medicines containing natural compounds as neem cake and extract are eco-friendly and could be efficiently applied in soil in a sustainable way.

Ecotoxicological effect of fipronil and its metabolites on Folsomia candida in tropical soils.

The aim of this study is to evaluate the toxicity of the fipronil and its metabolites, fipronil sulfone and fipronil desulfinyl on Folsomia candida. Three types of soils were used to perform the ecotoxicological tests, two natural soils (Oxisol and Entisol), and an artificial substrate (Tropical Artificial Soil). The treatments consisted of increasing doses of a veterinary medicinal product with active ingredient based on fipronil, and of its two main metabolites, fipronil sulfone and fipronil desulfinyl. The doses of fipronil were 0.00, 0.02, 0.04, 0.08, 0.15, 0.30, 0.60, and 1.00 mg kg-1 of the active ingredient. For fipronil sulfone and fipronil desulfinyl the doses tested were: 0.00, 0.01, 0.02, 0.04, 0.06, 0.08, 0.15, 0.30, 0.60, 1.00, and 5.00 mg kg-1. The effects of toxicity on F. candida were evaluated by survival and reproduction tests, based on the methods described by ISO 11267. There was a completely randomized design, with six replicates for the fipronil tests and eight for the metabolites. We show that fipronil and its metabolites, even at very low concentrations, are toxic to F. candida. Reduction of reproduction can be observed at concentrations of 0.15 mg kg-1. There was little difference in toxicity (LC50 and EC50) between fipronil and its metabolites. Rather, differences were related more to soil type, where the artificial soil was more sensitive than the two natural soils (Oxisol and Entisol). We conclude that it is important to perform ecotoxicological tests in natural soils, in order to generate more realistic representations of veterinary drug toxicity on the environment.

Injectable diphenyl diselenide supplementation in dairy sheep / Suplemento de difenil diselenuro inyectable en ovejas lecheras

ABSTRACT Objective. The aim of this study was to evaluate the influence of subcutaneous supplementation with diphenyl diselenide ((PhSe)2) in dairy sheep infected with gastrointestinal nematodes on animal health and possible damage to environment when the feces of these animals will be used for fertilizing. Materials and methods. The experiment was performed using 16 primipara dairy sheep, that were divided into two groups: the group A as control and the group B supplemented with 3 µmol/kg of (PhSe)2 subcutaneously. Blood samples were used to determine the hepatic function, as well as the protein and lipid metabolism in animals. Feces were used to determine the number of helminths eggs per gram of feces (EPG), as well as used for ecotoxicology tests. Results. The (PhSe)2 supplementation not affected the helminths reproduction, since the EPG did not differ (p>0.05) between groups. Total protein and globulin levels increase (p<0.05) in supplemented animals, while the seric alanine aminotransferase (ALT) levels decrease (p<0.05) in the end of experimental design. Cholesterol levels increase (p<0.05) in the supplemented animals, while triglycerides, albumin and urea not differ between groups (p>0.05). The feces of supplemented sheep not interfered the springtails reproduction. Conclusions. At the administered dose, the (PhSe)2 is not able to control the parasitism, however, it did increase the globulins and cholesterol levels, that are important to immune response and for sheep reproduction, respectively. Also, the feces of supplemented animals with (PhSe)2 can be used as organic fertilizing, without negative impacts to environment.

RESUMEN Objetivo. El objetivo de este estudio fue evaluar la influencia de la suplementación subcutánea con diselenuro de difenilo (PhSe)2 en ovejas lecheras infectadas con nematodos sobre la salud animal y posible daño al ambiente cuando las heces de estos animales se utilicen para fertilizar. Materiales y métodos. El experimento se realizó utilizando 16 ovejas lecheras, que se dividieron en dos grupos: el grupo A se usó como control y el grupo B se suplementó con 3 µmol/kg of (PhSe)2 vía subcutánea. Se utilizaron muestras de sangre para determinar la función hepática, así como el metabolismo de proteínas y lípidos en animales. Las heces se utilizaron para determinar el número de huevos por gramo de heces (EPG), así como para las pruebas de ecotoxicología. Resultados . La suplementación (PhSe)2 no afectó la reproducción de helmintos. Los niveles totales de proteína y globulina aumentan (p<0.05) en los animales suplementados, mientras que los niveles séricos de alanina aminotransferasa (ALT) disminuyen (p<0.05) al final del diseño experimental. Los niveles de colesterol aumentan (p<0.05) en los animales suplementados, mientras que los triglicéridos, la albúmina y la urea no difieren entre los grupos (p>0.05). Las heces de ovejas suplementadas no interferían en la reproducción de las colas de caballo. Conclusiones. A la dosis administrada, el (PhSe)2 no es capaz de controlar el parasitismo; sin embargo, aumenta los niveles de globulinas y colesterol, que son importantes para la respuesta inmune y para la reproducción, respectivamente. Las heces de animales suplementados pueden usarse como fertilizantes orgánicos, sin impactos negativos en ambiente.

Toxicity of four veterinary pharmaceuticals on the survival and reproduction of Folsomia candida in tropical soils.

This study aimed to evaluate the effect of veterinary pharmaceuticals (VPs) used to control endo- and ectoparasites in ruminants, on the survival and reproduction of the collembolan species Folsomia candida. Standard ecotoxicological tests were conducted in Tropical Artificial Soil and the treatments consisted of increasing dosages of four commercial products with different active ingredients: ivermectin, fipronil, fluazuron and closantel. Ecotoxicological effects were related to the class and mode of action of the different compounds. Fipronil and ivermectin were the most toxic compounds causing a significant reduction in the number of juveniles at the lowest doses tested (LOECreprod values of 0.3 and 0.2 mg kg-1 of dry soil, respectively) and similar low EC50 values (fipronil: 0.19 mg kg-1 dry soil, CL95% 0.16-0.22; ivermectin: 0.43 mg kg-1 dry soil, CL95% 0.09-0.77), although the effects observed in the former compound were possibly related to a low adult survival (LC50 of 0.62 mg kg-1 dry soil; CL95%: 0.25-1.06). For the latter compound no significant lethal effects were observed. Fluazuron caused an intermediate toxicity (EC50 of 3.07 mg kg-1 dry soil, CL95%: 2.26-3.87), and also here a decrease in adult survival could explain the effects observed at reproduction. Closantel, despite showing a significant reduction on the number of juveniles produced, no dose-response relationship nor effects higher than 50% were observed. Overall, all tested compounds, especially ivermectin, when present in soil even at sub-lethal concentrations, can impair the reproduction of collembolans and possibly other arthropods. However, the actual risk to arthropod communities should be further investigated performing tests under a more realistic exposure (e.g., by testing the dung itself as the contaminated matrix) and by deriving ecotoxicologically relevant exposure concentration in soil derived from the presence of cattle dung.

Influence of cypermethrin on avoidance behavior, survival and reproduction of Folsomia candida in soil.

Cypermethrin is a pyrethroid widely used in agriculture and in control of animal ectoparasites, being effective against a large number of insects. Therefore, this study aimed to evaluate the effects of cypermethrin on soil fauna using reproduction and behavior ecotoxicological tests with the springtail Folsomia candida. The surface layer of a soil characteristic of the western region of the Santa Catarina State, classified as Typic Dystrupept, was used as test substrate. The treatments on both tests consisted of five concentrations of cypermethrin (0, 7.5, 15.0, 22.5, and 30.0mgkg(-)(1)) corresponding to 0, 1.5, 3.0, 4.5, and 6.0gm(-2), respectively. This range was chosen according to technical instruction for the use of this product in broilers beds (that are used afterwards as organic fertilizer in soil) that recommends 15mgkg(-1) (3.0gm(-2)). The results obtained with tests for F. candida showed toxicity at all doses tested, following a dose-related response resulting in reduction in survival rate (LC50 of 18.41mgkg(-1), equivalent to 3.8gm(-2)), in the number of juveniles (EC50 of 15.05mgkg(-1), corresponding to 3.01gm(-2)), and an increase in avoidance response (AC50 of 29mgkg(-1), corresponding to 5.8gm(-2)). Although more studies are needed focusing on the fate of cypermethrin in soil when the poultry beds are used as fertilizer and how it may affect soil fauna, data obtained in this study, by showing effects within the range of the doses that are recommended implies that caution and possible mitigation measures should be taken when using this compound.