Effects of alpha lipoic acid supplementation on post-thaw quality of drone semen.

This study aimed to determine the effect of alpha-lipoic acid (ALA) on post-thaw quality of bee semen. In the study, semen from sexually mature drone were collected. A series of experiments were carried out in which the retrieved semen was diluted with diluents containing different ALA concentrations or without ALA supplement (control). Cryopreserved sperm were thawed, and evaluated for motility (phase-contrast microscope), plasma and acrosomal membrane integrity, mitochondrial membrane potential, and DNA fregmantation. The results obtained showed that the highest motility after thawing was observed in the groups containing ALA 0.25 mmol (P < 0.05). Likewise, plasma membrane integrity was found to be better preserved in the ALA 0.25 mmol-added group than in other groups. Acrosomal integrity were also higher in the ALA-containing groups than in the control group (P < 0.05). The results of this study show that ALA supplementation especially at 0.25 mmol improved post-thawed sperm motility, plasma membrane functionality, and mitochondrial membrane potantial quality of honeybee semen.

Effects of temperature adjustment with a heating device in weak honey bee colonies in cold seasons.

Temperature adjustment was used to buffer against changes in external environmental temperature by a heating device. Two groups of honey bee colonies Apis mellifera anatoliaca were used: one as experimental (20) and the other control (10), which were equalized in terms of the number of brood frames, frames with bees, food, hive materials, and health treatments. The experimental colonies were heated during the cold season, and the temperature and humidity inside the hive were recorded. The number of frames of brood, frames of bees, and Varroa destructor mite numbers were also determined for all hives. Results suggest that the number of brood frames and frames with bees increased significantly in the hives with the heating treatment. However, varroa mite numbers also increased significantly in the heated colonies in comparison to the control colonies. Colony losses were significantly less (15%) in heated colonies compared to a 40% loss in control colonies. This is the first account demonstrating that using simple heating devices can support weak colonies during the cold season in general, and colony losses can be reduced significantly from this heating treatment in cold seasons.

Toxicity assessment of chronic exposure to common insecticides and bee medications on colony development and drones sperm parameters.

The effect of agrochemicals and beekeeping treatments on drones have not been widely investigated compared to workers or queens. In the present study, we investigated the chronic exposure of chemicals set (deltamethrin, acetamiprid, oxalic acid, fumagillin, and amitraz) on some sperm parameters and on the histomorphology of seminal vesicles. We also assessed the colony development and nosema load before and after the exposure. Thirty native Apis mellifera anatolica honeybee colonies with sister queens equalized with brood and total frame of bees were used for this experiment. Five colonies were used for each group. Deltamethrin, acetamiprid and fumagillin were given as oral chronic exposure at final concentrations of 25.10-6 mg L-1, 0.01 m L-1 and 50 mg L-1 respectively in syrup solution (50/50). Colonies were exposed to oxalic acid by spraying 5 mL per frame space of 3% (w/v) of oxalic acid dihydrate. Finally, the amitraz was applied based on the manufacturer's instructions. The concentrations chosen represented the field-realistic concentrations and those used by beekeepers in the region. Results showed that deltamethrin reduced brood production. In the same group, we found a high increase in nosema load. All treatments decreased sperm count except for fumagillin but this compound increased sperm mortality and increased the percentage of sperm with defected acrosome integrity. The amitraz exhibited a high sperm mortality and high percentage of sperm with defected membrane integrity function. The sperm parameters such as the count, the motility, the acrosome integrity, the membrane function of sperm, and the histomorphology of seminal vesicles of drones exposed to oxalic acid were the most affected. Bee medications commonly used such as oxalic acid and fumagillin should be more investigated and should be considered by beekeepers and particularly queen breeders.

Successful cryopreservation of honey bee drone spermatozoa with royal jelly supplemented extenders.

The aim of the present study was to evaluate different concentrations of royal jelly (RJ) supplemented extenders for post-thawing quality of drone sperm. Semen samples were collected from sexually mature drones. Pooled semen was diluted with extender without RJ (control) or supplemented with different concentrations of RJ (1, 2, 4 or 8%). Sperm motility, plasma membrane functional integrity, and acrosomal integrity were evaluated. At post thaw, the highest sperm motility and acrosomal integrity rates were obtained in the RJ1 group. Functional integrity of sperm membrane was better preserved in the RJ1 and RJ2 groups compare to the other groups. The study shows that RJ supplemented extenders have beneficial effects on drone semen parameters. The results of the present study demonstrated advantage of using 1% RJ supplemented extender.