American foulbrood is a dangerous world-wide spread disease of honey bees caused by the Paenibacillus larvae bacterium. Antibiotic treatments are less effective and leave residues in bee products. It is therefore necessary to find an alternative, especially using natural ingredients such as plant essential oils, probiotics, fatty or organic acids. Two strains of P. larvae were used for this study: CCM 4488, a strain from the Czech collection of micro-organisms and a Slovak field strain which was isolated from infected bee combs and characterized on the basis of biochemical properties. Plant essential oils of sage (Salvia officinalis), anise (Pimpinella anisum), oregano (Origanum vulgare), caraway (Carum carvi), thyme (Thymus vulgaris), rosemary (Rosmarinum officinalis), clove (Syzygium aromaticum), camomile (Chamomilla recutita) and fennel (Foeniculum vulgare) were used for the testing of the inhibitory activity against P. larvae. Essential oils at amounts of 5 µl and 10 µl were applied to sterile discs on MYPGP agar; inhibition zone diameters were measured after 24-h incubation at 37 °C. The strongest inhibitory activity against both P. larvae strains was noted in case of the essential oils from oregano, thyme and clove; essential oils from camomile, rosemary and fennel showed no or weak antibacterial activity. Medium strong inhibition activity was recorded in case of previously untested essential oil from Carum carvi. There was a difference in sensitivity of both tested strains to essential oils. Our study confirmed that some essential oils can be used in the prevention of American foulbrood but further experiments aimed at their influence on physiological intestinal microflora of honey bees must be performed.
The population and distribution of the European brown bear (Ursus arctos) in Slovakia are expanding as bears were observed beyond the southern border of the country in Hungary. This study presents the authors' experience with field anaesthesia of wild brown bears trapped in a custom-made container trap and of free-ranging individuals. A total of 25 bears were captured and translocated using a specially designed metal cage trap. The study compared the effectiveness of three anaesthetic protocols in managing both free-ranging and trapped bears. For juveniles, or small adults up to 70 kg body weight (BW), ketamine-xylazine mixture was used at doses of 3.0–4.0 mg kg−1 ketamine and 1.0–1.5 mg kg−1 xylazine BW. The immobilisation of free-ranging bears, which are usually attracted by municipal solid garbage, was performed remotely using PneuDart darts with 2–3 ml of anaesthetics. For this purpose, tiletamine-zolazepam-detomidine (T-Z-D) was preferred at a dose of 1.7–2.5 (T) mg kg−1, 1.7–2.5 (Z) mg kg−1, and 0.1–0.2 (D) mg kg−1 BW. Induction time was from 7 to 18 min post darting with the average of 12.04 min. The same combination was applied to bears trapped in a container trap, with anaesthesia lasting from 40 to 150 min. If T-Z-D was used, no further anaesthetic was needed. In all cases, anaesthesia was antagonised by atipamezole at a dose of 0.15–0.225 mg kg−1 BW. Atipamezole was injected at a half dose intramuscularly and a half dose subcutaneously at the time when the palpebral reflex reappeared and the bear was able to move his tongue. It was shown that the T-Z-D mixture is a safe, low-volume anaesthetic darting protocol that is reversible, has minimal adverse effects on physiological parameters, and has a sufficient duration. The results can be used to manage large carnivore populations in the Carpathian region.
American foulbrood is amongst the most dangerous diseases of the bee-family affecting many honeybee colonies worldwide. In countries of European Union, based on veterinary legislation, the bee colonies tested positive to American foulbrood are eradicated with high economic losses. It is therefore necessary to look for effective prevention, especially by the using of natural ingredients such as probiotics. In this study, we used lactobacilli isolated from digestive tracts of adult healthy honey bees and selected based on their good probiotic properties and ability to inhibit the growth of Paenibacillus larvae. These isolates were identified as Lactobacillus brevis and Lactobacillus plantarum. Night cultures of both strains were used for the preparation of probiotic suspensions and pollen was selected as an appropriate carrier for application of probiotic lacto-bacilli to the hives. Half a litre of pollen suspension was prepared for each hive. The suspension for experimental hives contained probiotic lactobacilli in concentration of 107–108 CFU.ml−1. Bees in control hives received pollen suspension without addition of probiotic lacto-bacilli. The suspensions were supplied to bees three times, once a week. Before and during administration of probiotics, samples of honey bees from each hive were taken every week and numbers of lactobacilli, P. larvae, enterobacteria and coliform bacteria were determined in their digestive tracts. Four weeks after the first administration of probiotic-pollen solution the numbers of lactobacilli were increased approximately by 0.5 log. Before starting this experiment, P. larvae (approx. 107 CFU.ml−1) were detected in digestive tracts of honey bees. In the experimental group after 3 weeks and in the control group after 4 weeks, no viable counts of P. larvae were found. The numbers of enterobacteria, coliform bacteria and Bacillus sp. decreased in both groups. During the experiment the health and condition of the hives were monitored. In addition, also monitored were: the development of the bee colony, the number of dead bees, the amount of hive debris, the aggressiveness of the bees, and the amount of honey spun; later during the autumn treatment also the fall of Varroa jacobsoni was noted. In the experimental and control groups, we recorded a decrease in the amount of hive debris. Only in the experimental group was a slightly above-average development of the bee colony, slightly above-average honey yields and a 70 % lower drop of Varroa mites. Based on these results, we assumed that the probiotic-pollen solution had a positive influence on the composition of microbiota in bee digestive tracts and it can increase resistance to P. larvae. It also had a positive effect on the health and condition of the bee colony. Probiotic-free pollen solution showed similar but weaker effects.
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