RESUMO
Bee pollen is recommended as dietary supplement due to immunostimulating functions including antioxidant, anti-inflammatory and anti-carcinogenic properties. Nevertheless, the effectiveness of such properties is still not well understood. As diet can be associated with animal performance, microbiota modulation and potentially factor for cancer, this study aimed to analyze if bee pollen could influence growth, gut microbial and skin cutaneous melanoma development in zebrafish. Control diets based on commercial flakes and Artemia were compared with the same diet supplemented with bee pollen. Fish weight gain, increased length, intestinal bacteria metagenomics analysis, serum amyloid A gene expression and cutaneous melanoma transplantation assays were performed. Bee pollen affected microbiota composition and melanoma development. Differential abundance revealed higher abundance in the control group for Aeromonadaceae family, Aeromonas and Pseudomonas genus, A. sobria, A. schubertii, A. jandaei and P. alcaligenes species compared with pollen diet group. Pollen group presented higher abundance for Chromobacterium genus and for Gemmobacter aquaticus, Flavobacterium succinicans and Bifidobacterium breve compared with control group. Unexpectedly, fish fed with bee pollen showed higher tumor growth rate and larger tumor size than control group. This is the first study to report intestinal microbial changes and no protective cancer properties after bee pollen administration.
Assuntos
Microbioma Gastrointestinal , Melanoma , Neoplasias Cutâneas , Animais , Abelhas , Dieta , Melanoma/etiologia , Pólen , Neoplasias Cutâneas/etiologia , Peixe-Zebra , Melanoma Maligno CutâneoRESUMO
Bees are recognized worldwide for their social, economic, and environmental value. In recent decades they have been seriously threatened by diseases and high levels of pesticide use. The susceptibility of bees to insecticides makes them an important terrestrial model for assessing environmental quality, and various biomarkers have been developed for such assessments. The present study aimed to evaluate the activity of the enzymes acetylcholinesterase (AChE), carboxylesterase (CaE), and glutathione-S-transferase (GST) in Africanized honeybees exposed to fipronil. The results showed that fipronil at a sublethal dose (0.01 ng/bee) modulates the activity of CaE in all isoforms analyzed (CaE-1, CaE-2, and CaE-3) in both newly emerged and aged bees, and does not affect the activity of AChE or GST. The recovery of the bees after fipronil exposure was also investigated, and these results demonstrated that even the cessation of fipronil ingestion might not lead to complete recovery of individual bees. Even at low doses, fipronil was shown to cause changes in the activity of key enzymes in bees. The possible consequences of these changes are discussed. Environ Toxicol Chem 2017;36:1652-1660. © 2016 SETAC.
Assuntos
Abelhas/efeitos dos fármacos , Inseticidas/farmacologia , Pirazóis/farmacologia , Acetilcolinesterase/metabolismo , Animais , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glutationa Transferase/metabolismo , Isoformas de ProteínasRESUMO
The present study was intended to evaluate the responses of enzymes in the honeybee Apis mellifera after exposure to deltamethrin, fipronil, and spinosad and their use as biomarkers. After determination of the median lethal doses (LD50), honeybees were exposed at doses of 5.07 ng/bee and 2.53 ng/bee for deltamethrin, 0.58 ng/bee and 0.29 ng/bee for fipronil, and 4.71 ng/bee and 2.36 ng/bee for spinosad (equivalent to 1/10th [LD50/10] and 1/20th [LD50/20] of the LD50, respectively). The responses of acetylcholinesterase (AChE), carboxylesterases (CaEs-1-3), glutathione-S-transferase (GST), catalase (CAT), and alkaline phosphatase (ALP) were assessed. The results showed that deltamethrin, fipronil, and spinosad modulated these biomarkers differentially. For the enzyme involved in the defense against oxidative stress, fipronil and spinosad induced CAT activity. For the remaining enzymes, 3 response profiles were identified. First, exposure to deltamethrin induced slight effects and modulated only CaE-1 and CaE-2, with opposite effects. Second, spinosad exhibited an induction profile for most of the biomarkers, except AChE. Third, fipronil did not modulate AChE, CaE-2, or GST, increased CAT and CaE-1, and decreased ALP. Thus, this set of honeybee biomarkers appears to be a promising tool to evaluate environmental and honeybee health, and it could generate fingerprints to characterize exposures to pesticides.
Assuntos
Abelhas/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Inseticidas/toxicidade , Fosfatase Alcalina/metabolismo , Animais , Abelhas/enzimologia , Biomarcadores/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Catalase/metabolismo , Combinação de Medicamentos , Glutationa Transferase/metabolismo , Macrolídeos/toxicidade , Nitrilas/toxicidade , Pirazóis/toxicidade , Piretrinas/toxicidadeRESUMO
Fipronil is a neurotoxic insecticide that inhibits the gamma-aminobutyric acid receptor and can affect gustative perception, olfactory learning, and motor activity of the honeybee Apis mellifera. This study determined the lethal dose (LD50) and the lethal concentration (LC50) for Africanized honeybee and evaluated the toxicity of a sublethal dose of fipronil on neuron metabolic activity by way of histochemical analysis using cytochrome oxidase detection in brains from worker bees of different ages. In addition, the present study investigated the recovery mechanism by discontinuing the oral exposure to fipronil. The results showed that mushroom bodies of aged Africanized honeybees are affected by fipronil, which causes changes in metabolism by increasing the respiratory activity of mitochondria. In antennal lobes, the sublethal dose of fipronil did not cause an increase in metabolic activity. The recovery experiments showed that discontinued exposure to a diet contaminated with fipronil did not lead to recovery of neural activity. Our results show that even at very low concentrations, fipronil is harmful to honeybees and can induce several types of injuries to honeybee physiology.