Influence of winter feeding on colony development and the antioxidant system of the honey bee, Apis mellifera

The effects of supplementary feeding (artificial diet cake + sucrose syrup supplemented with vitamin C) for different periods (feeding for 12, 15 and 18 weeks) on colony development, protein content and antioxidant system in newly emerged workers were investigated from October to March for two consecutive beekeeping seasons. Sugar syrup was used as the control. The results revealed that there was a marked increase in colony growth parameters (sealed brood areas and adult bee population sizes) in colonies provided with supplemental diet for different periods compared to control colonies. Moreover, colonies fed longest (feeding for 18 weeks) recorded significantly higher sealed brood areas and adult bee population sizes in comparison to other treatment groups. Also, activities of superoxide dismutase (SOD) and catalase (CAT) enzymes together with levels of glutathione (GSH) and lipid peroxidation (LPO) were measured in newly emerged honey bee workers sampled from colonies fed supplemental diet for different periods and control group. There was a clear improvement in the antioxidant system in bee colonies that were provided with supplemental diet for 18 weeks compared to other treatments and control ones. This suggests that honey bee workers supplemented with artificial feeding during the winter season possess mechanisms that reduce their oxidative stress. Together, our results suggest that supplemental winter feeding for 18 weeks (from 1 November to 11 March) has the potential to improve colony development and health during overwintering, a period of elevated colony losses.