Avaliação do mel como substrato para contaminação fúngica no ambiente da colméia

Abstract

Honey is a food produced by bees from the nectar of flowers collected and processed by the digestive enzymes of insects, stored in combs in their hives to serve them food. The Brazilian apiculture (branch of agriculture that studies of honey bees) has suffered high losses of honey bees, due to a number of diseases that affect the hives, putting them at risk. Many species of yeasts and molds can grow in the hive using honey as a substrate, such as the genus Aspergillus, which is important because it contains species that produce mycotoxins and / or pathogenic to bees. The Brazilian sac brood disease (BSB) is a disease with high mortality, characterized by death in the pre-pupa or pupa and that have occurred in southeastern Brazil, with substantial losses to beekeeping. However, its etiology is unknown in the region, which were dismissed any similarity to the European Creates bagged caused by Sac Brood Virus (SBV), and the Stryphnodendron polyphyllum (Fabaceae, Mimosoidea), the common name barbatimão. The objectives of this study were 1) to assess the fungal contamination in honey bee brood and thus determining influence on the occurrence of BSB in the environment of the hive, in Rio de Janeiro, 2) enumerate the fungal propagules in samples of honey in the comb, and the young (pre-pupae and pupae) from apiaries located in regions affected by BSB, 3) determine the frequency and identify the mycoflora total, 4) identify fungal species pathogenic to bees, 5) characterize toxigenic profile isolated species of the genus Aspergillus. A total of 43 honey samples and 43 samples of offspring (larvae and pupae) was purchased from apiaries that have already expressed the CEB, in the municipalities of Barra do Piraí, Mendes and Itaipava (endemic areas). Sampling occurred in the months corresponding to the period before, during and after - disease (based on data from recent outbreaks). Analysis of the mycoflora were performed by spread plate on the culture media dichloran rose bengal chloramphenicol agar (DRBC) and dichloran 18% glycerol agar (DG18). The total fungal counts were expressed as cfu g-1. We determined the number of samples and frequency of isolation (%) of fungal genera and the relative density of species. The determination of toxigenic fungi was done using the technique of thin layer chromatography (TLC). The values of total fungal counts were similar in both media DRBC and DG18 for the samples of offspring. The highest counts were observed in samples of honey in the comb, with 7,7 x 104 cfu g-1 on DRBC medium and 5.9 x 104 cfu g-1 in DG18 medium. Aspergillus, Penicillium and Cladosporium were the most frequently isolated both in the honey comb, as in the offspring. Aspergillus niger, A. flavus and Penicillium citrinum showed the highest relative density in honey and brood. In the TLC analysis for the fungi isolated honey in the comb, were not observed for positive strains isolated species of the genus Aspergillus. Among the strains analyzed in the mycoflora of the larvae, there is presence of positive strains for toxigenic profile of A. flavus in samples from Barra do Pirai and Itaipava. For strains producing ochratoxins, the result was 100% negative for all sites studied. The fungi found in this study can be related to losses bee in Rio de Janeiro, but is not present apparent direct with BSB. However, more studies are needed to identify the mycoflora of honey and brood, correlating the possible species that produce mycotoxins with the mycoflora present in the substrate, promoting so help on the etiology of BSB in this state. Keywords: fungi, honey, brood, bees.