Beneficial Bacteria and Plant Extracts Promote Honey Bee Health and Reduce Nosema ceranae Infection

Abstract

The research aims to give new insights on the effect of administering selected bacterial strains, isolated from honey bee gut, and/or a commercial plant extract blend (HiveAlive®) on Nosema ceranae. Analyses were first performed under laboratory conditions such as different infective doses of N. ceranae, the effect of single strains and their mixture and the influence of pollen administration. Daily survival and feed consumption rate were recorded and pathogen development was analysed using qPCR and microscope counts. Biomarkers of immunity and physiological status were also evaluated for the different treatments tested using one bacterial strain, a mixture of all the bacteria and/or a plant extract blend as treatments. The results showed an increase of abaecin transcript levels in the midgut of the honey bees treated with the bacterial mixture and an increased expression of the protein vitellogenin in the haemolymph of honey bees treated with two separate bacterial strains (Bifidobacterium coryneforme and Apilactobacillus kunkeei). A significant effectiveness in reducing N. ceranae was shown by the bacterial mixture and the plant extract blend regardless of the composition of the diet. This bioactivity was seasonally linked. Quantitative PCR and microscope counts showed the reduction of N. ceranae under different experimental conditions. The antiparasitic efficacy of the treatments at field conditions was studied using a semi-field approach which was adapted from research on insecticides for the first time, to analyse antiparasitic activity against N. ceranae. The approach proved to be reliable and effective in validating data obtained in the laboratory. Both the mixture of beneficial bacteria and its association with Hive Alive® are effective in controlling the natural infection of N. ceranae in honey bee colonies.

Experimental evidence and meta-analysis indicate the negative effect of nosemosis on the survivorship of honeybees

“…Significant attention is paid to the application of Good Beekeeping Practices as a form of prevention (Formato et al 2022). However, while these methods yield some results, they still prove insufficient (Huang et al 2013, Holt and Grozinger 2016, Garrido et al 2023, Lang et al 2023, Prouty et al 2023). There is a pressing need for further research on N. ceranae , especially in the context of its effective control strategies that consider the microbiological safety of the hive products (i.e.…”

Vairimorpha (Nosema) ceranae can promote Serratia development in honeybee gut: an underrated threat for bees?

“…Sequence chromatograms were analyzed, manually edited, and classified using BLAST tool from NCBI. The honeybee survival test using the Serratia isolated strains was performed according to Garrido et al. (2024) , whereas the mortality and diet consumption information are reported in the Supplementary Materials of Garrido et al.…”

“…Some DNA samples were stored as part of wider studies according to Braglia et al. (2021) and Garrido et al. (2024) , and others were obtained in this study ( Table 1 ).…”

“…Honeybees were inoculated with 5 × 10 2 , 5 × 10 3 , and 5 × 10 4 V . ceranae spores according to Garrido et al. (2024) .…”

“…Moreover, the synergy with the gut pathogen V. ceranae was assessed and evaluated after the administration of a feed supplement based on microorganisms, pollen, and the antibiotic fumagillin already tested against Vairimorpha ( Alberoni et al., 2018 ; Garrido et al., 2024 ). In particular, the presence and amount of the co-occurring and opportunistic pathogen Serratia were taken into consideration in a sample subset produced in Garrido et al. (2024) and a possible correlation with V. ceranae was considered.…”