Effects of Plant-Based Supplement on Oxidative Stress of Honey Bees (Apis mellifera) Infected with Nosema ceranae

Abstract

One of the most important approaches in the prevention and treatment of nosemosis is the use of herbal preparations as food supplements for bees. Therefore, the aim of this study was to investigate the effects of a plant-based supplement branded as “B+” on honeybees in a laboratory experiment. Four experimental groups were established: treated group (T), N. ceranae-infected and treated group (IT), N. ceranae-infected group (I) and non-infected group (NI). Survival, N. ceranae spore load and oxidative stress parameters together with expression levels of antioxidant enzyme genes and vitellogenin gene were monitored. The mortality in the T, IT and NI groups was significantly (p < 0.001) lower than in than in the I group. Within Nosema-infected groups, the IT group had a significantly lower (p < 0.001) number of N. ceranae spores than the I group. In addition, expression levels of genes for antioxidant enzymes were lower (p < 0.001) in the IT group compared to the I group. The concentration of malondialdehyde and the activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione S-transferase) were significantly lower (p < 0.001) in the IT group compared to the I group. No negative effects of the tested supplement were observed. All these findings indicate that the tested supplement exerted beneficial effects manifested in better bee survival, reduced N. ceranae spore number and reduced oxidative stress of bees (lower expression of genes for antioxidant enzymes and oxidative stress parameters).

Potential of Wormwood and Oak Bark-Based Supplement in Health Improvement of Nosema ceranae-Infected Honey Bees

“…Similarly, thymol was shown to possess an anti-Nosema effect in several studies [18,45,65]. In our previous studies, the anti-Nosema effect was achieved using commercial supplements such as "B+" [19] and "BEEWELL AminoPlus" [15] in laboratory conditions, but also in hive experiments [8,27]. Anti-Nosema effects of mushroom species Agaricus bisporus and A. blazei were observed without any side effects when preventively applied [16,17].…”

“…In previous studies, different types of diets were tested for their effect on Nosema-infected bees. It has been proven that some commercially available supplements like B+ [19] and "BEEWELL AminoPlus" [15] showed a positive effect on the survival of bees infected with Nosema as well as the mushroom extracts of Agaricus blazei and A. bisporus [16,17] and various plant extracts either aqueous extracts of plants such those of Thymus vulgaris, Salvia officinalis, Plantago lanceolata and Rumex acetosella [56], or alcoholic extracts such those of Rosmarinus officinalis and Ugni molinae [23].…”

“…Many studies investigated natural strategies against nosemosis, with plant and algal extracts as well as synthetic vitamin/mineral mixtures giving the best results [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]). These products, administrated to bees before or after the Nosema infection, significantly reduced mortality and infection rates [15][16][17][18][19]. It has also been proven that the aqueous extracts of Agaricus braziliensis and A. bisporus mushrooms positively influence Nosemainfected bees, supporting the survival of infected bees [16,17].…”

“…Moreover, N. ceranae infection negatively affects honey bees by reducing olfactory learning and memory [10], causing premature foraging in worker bees [9,11,12], decreasing homing ability [13], and weakening flight ability [14]. Finally, N. ceranae leads to suppression of the immune response and increased oxidative stress in bees [15][16][17][18][19].…”

“…One of the most important approaches is the application of supplements in the bee diet [4,23]. Many dietary supplements improve honey bee strength, immunity, and performance, thereby contributing to the maintenance of healthy colonies [8,15,19,[24][25][26][27][28]. Many studies investigated natural strategies against nosemosis, with plant and algal extracts as well as synthetic vitamin/mineral mixtures giving the best results [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]).…”