A comparison of sublethal effects of nanosized particles zinc oxide , silver , carbon black , titanium oxide and cerium ( iv ) oxide on carnolian honey bees

Nowadays, commercial mass rearing of honeybee queens combined with their storage in cages or in mating hives (ca. 2500 bees) is a standard procedure, particularly in Central Europe, e.g. in Poland. The cage environment, however, is significantly different from the hive one. It may be assumed that the commercial intensification of queen rearing, particularly the cage storage of queens, leads to reduction in their quality, including their biochemical defense system, which comprises, i.a. the hemolymph antioxidant system. The aim of the research was to determine enzymatic antioxidant activities (SOD (superoxide dismutase) and CAT (catalase)) and TAC (total antioxidant capacity) levels in the hemolymph of 8-dayold virgin queens which had been kept in queen cages or in mating hives from their emergence. Two queen groups were created on the day of their emergence. In the first one, the queens (n = 70) were individually placed into 70 queen cages, 10 worker bees with candy in each, and kept for 7 days there. Then, 10 pooled hemolymph samples, with the hemolymph of 7 queens in each, were taken. In the second group, the queens (n = 70) were individually placed in 70 mating hives without the possibility of mating flights and kept there for 7 days. The hemolymph sampling protocol was the same as in the first group (10 pooled samples). The activities of SOD, CAT and the level of TAC were determined with a commercial kit in each sample. The enzymatic antioxidant activities and TAC levels were higher in the hemolymph of the queens kept in the mating hives than in those kept in the cages. As expected, the queens kept in the mating hives had more sufficient biochemical defense. Higher antioxidant system in the mating hives may be associated with a more diverse diet, better care of bees, defensive mechanism of neutralization of xenobiotics, and better protection against ROS (reactive oxygen species) and oxidative damage of proteins and DNA. Consequently, the higher activity of the antioxidant system may make for better biochemical defense, that in turn is related to less stress. It also affects the ability to detoxify metabolites and shows higher antipathogen activities compared to the caged queens.