Selenium Toxicity to Honey Bee (Apis mellifera L.) Pollinators: Effects on Behaviors and Survival

We know very little about how soil-borne pollutants such as selenium (Se) can impact pollinators, even though Se has contaminated soils and plants in areas where insect pollination can be critical to the functioning of both agricultural and natural ecosystems. Se can be biotransferred throughout the food web, but few studies have examined its effects on the insects that feed on Se-accumulating plants, particularly pollinators. In laboratory bioassays, we used proboscis extension reflex (PER) and taste perception to determine if the presence of Se affected the gustatory response of honey bee (Apis mellifera L., Hymenoptera: Apidae) foragers. Antennae and proboscises were stimulated with both organic (selenomethionine) and inorganic (selenate) forms of Se that commonly occur in Se-accumulating plants. Methionine was also tested. Each compound was dissolved in 1 M sucrose at 5 concentrations, with sucrose alone as a control. Antennal stimulation with selenomethionine and methionine reduced PER at higher concentrations. Selenate did not reduce gustatory behaviors. Two hours after being fed the treatments, bees were tested for sucrose response threshold. Bees fed selenate responded less to sucrose stimulation. Mortality was higher in bees chronically dosed with selenate compared with a single dose. Selenomethionine did not increase mortality except at the highest concentration. Methionine did not significantly impact survival. Our study has shown that bees fed selenate were less responsive to sucrose, which may lead to a reduction in incoming floral resources needed to support coworkers and larvae in the field. If honey bees forage on nectar containing Se (particularly selenate), reductions in population numbers may occur due to direct toxicity. Given that honey bees are willing to consume food resources containing Se and may not avoid Se compounds in the plant tissues on which they are foraging, they may suffer similar adverse effects as seen in other insect guilds

Bioequivalence of three florfenicol preparations in broilers

This study was aimed to determine the bioequivalence of three different preparations of florfenicol using non-drugged broiler chickens. A total of 28 broiler chickens aging 30-day were divided into four equal groups; these were Group I, II, III, and IV. The birds of Group I (for effective substance) were given intravenous (i.v.) administration of florfenicol dosed at 40 mg/kg body weight (b.wt.). The birds of Group II (for reference drug), Group III (for test-1 drug), and Group IV (for test-2 drug) received florfenicol preparations with water (dosed at 40 mg/kg b.wt.) through intracrop administration. Blood samples were collected periodically from the birds of all four groups, and blood plasma was separated. Levels of florfenicol and its metabolite (florfenicol amine) in the plasma were measured by High Performance Liquid Chromatography (HPLC). In this study, the limit of detection (LOD) for florfenicol and florfenicol amine were recorded as 0.017 and 0.78 ?g/mL, respectively. On the other hand, the recovery of florfenicol and florfenicol amine were 83.4-84.6 and 82.2-83.8%, respectively. Based on the values of area under the curve (AUC), maximum concentration (Cmax), and time to maximum concentration (Tmax), test-1 drug was found to be acceptable, whereas test-2 drug was remained below the acceptable limits (80-125%) of AUC and Cmax. Thus, it was concluded that test-1 drug was bioequivalent as compared to the reference drug

Total testosterone, cortizol, growth hormone and fluorine levels in fluorine intoxicated rabbits

WOS: 000168884800010In this study, the effects of fluorine given subchronically (70 days) in drinking water (1, 10, 40 mg/L) were assessed in New Zealand male rabbits and their effects on total testosterone, cortisol and growth hormone (GH) levels were determined. Blood samples were taken from control and experimental groups after 0, 21 and 70 days and total testosterone, cortisol, GH and fluorine levels were measured. As a result, in animals given 10 mg/L fluorinated water, on the 21(st) day there was a statistically significant (p<0.01) drop in the cortisol levels and it was found that the drop in the testosterone levels and the rise in the GH levels were statistically insignificant. In animals given 10 mg/L fluorinated water, the drops in the cortisol and GH levels on the 70(th) day were statistically significant (p<0.01). in animals given 40 mg/L fluorinated water, the drops in the cortisol and GH levels on the 21(st) day were statistically significant (p<0.01). Also, on the 70(th) day the drop in the testosterone levels was statistically significant (p<0.05) and the drop in the cortisol and GH was very significant (p<0.001). Fluorine levels significantly rose during the study (p<0.001). depending on the species, doses and duration of application