Determination of Honey Quality and Its Antibacterial Effects on Bee Health

Abstract

The impact of pathogens on apiculture has led to the rapid decline in bee colonies in some parts of the world. Evidence in literature on pathogenic resistance to conventional antibiotics indicates that the use of antibiotics to treat bee bacterial diseases has led to development of pathogenic resistance genes. Additionally, trace amounts of these chemicals contaminate bee products, affecting their quality. There’s need to investigate the possibility of employing natural forms of apitherapy to enhance bee health and colony sanitation. Honey is bees’ source of carbohydrates and also a major candidate for apitherapy as it has demonstrated immense potential in treating human diseases. However, little research has been done on the benefits of honey to the actual producers, the bees. This study investigated the quality and the prophylactic and therapeutic antibacterial potential of honey on bee health as a natural defense line and an alternative to antibiotic use. Bees were inoculated with bacteria and the bacteria density in the bees’ gut quantified over time in the prophylactic and therapeutic treatment groups using qRT-PCR (quantitative real time polymerase chain reaction). A choice experiment was used to determine the bees’ choice of honey when healthy and diseased. Further, GC-MS (Gas chromatography mass spectrometry) analysis was used to characterize the honey’s volatile and non-volatile extracts. Honey quality was assessed via phytochemical and physicochemical analyses. Honey influenced the bacterial density in the bees’ gut over the sampled time. In both treatments, all the six honey suppressed the levels of Serratia marcescens, an opportunistic pathogen to bees, and Escherichia coli an environmental bacteria proving their prophylactic and therapeutic ability against the pathogens. The healthy bees had no preference for any specific honey but made a faster choice for Kitui honey. The diseased bees portrayed a diet change in response to infection and preferred Kitui honey. Overally, the diseased bees made a faster choice compared to the healthy ones. Lastly, quality analysis of the honey showed high phytochemical content; phenols 186 mg GAE/mg, and flavonoids 129.2 mg QE/100 g. Variable quantities of physicochemical parameters; carbohydrates 81.5% and pH 4.2 were also recorded, these factors contribute to honey’s antibacterial activity. The volatile and non-volatile chemical profiles showed variability and similarities in the compounds present in each honey. Some of the compounds such as cedrol, 2,5-bis(1,1-dimethyl)-phenol, β-pinene, sibinene, 2,4-dimethyl-1-heptene and 2,5-bis(1,1-dimethylethyl)-phenol had proven antibacterial activity. This study’s findings indicate that bees’ diet plays a role in maintaining their health and they change their diet preference when diseased to seek honey with more therapeutic potential as evidenced by the chemical profiles, which contain antibacterial compounds. This new evidence provides an alternative form of treatment of bees’ diseases through diet to enhance their health and product quality while mitigating the catastrophes of using antibiotics which pose the risk of development of resistance.