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.本研究于两个连续养蜂季的10月至次年3月开展，旨在探究不同补饲周期（12周、15周及18周）的补饲方案（人工饲料饼+添加维生素C的蔗糖糖浆）对新羽化工蜂的蜂群发育、蛋白质含量及抗氧化系统的影响。实验以纯蔗糖糖浆作为对照。 结果显示，相较于对照组蜂群，各补饲周期的处理组蜂群的生长指标（封盖子脾面积与成年蜂种群数量）均显著提升。其中，补饲周期最长的18周组，其封盖子脾面积与成年蜂种群数量均显著高于其余处理组。 本研究同时测定了各补饲周期处理组与对照组的新羽化工蜂体内超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性，以及谷胱甘肽（GSH）水平与脂质过氧化（LPO）水平。结果表明，与其余处理组及对照组相比，补饲18周的蜂群其抗氧化系统得到显著改善。 该结果提示，冬季接受人工补饲的蜜蜂工蜂，可通过自身机制缓解氧化应激。综上，本研究结果表明，在蜂群损失率较高的越冬期开展18周的冬季补饲（11月1日至次年3月11日），可有效改善蜂群的发育状况与健康水平。