Low administration of bee pollen in the diet affects qualitative histological characteristics of bone in male rats

Bee pollen is often used as a dietary additive because it contains proteins and is rich in vitamins, minerals and phytochemicals. However, its impact on growth characteristics and bone microstructure is still poorly understood. Therefore, the objective of this study was to investigate the effect of low administration of bee pollen on selected growth characteristics and histological structure of femoral bones in rats. For this purpose, 1-month-old male Wistar rats were randomly divided into two groups of 5 animals each. In the control group (CG), rats were fed a commercial diet throughout the experiment (90 days). Rats of experimental group (EG) received standard diets with a 0.2% addition of bee pollen for the same time period of treatment. At the end of the experiment, macroscopical and microscopical structures of femoral bones from all rats were analysed using analytical scales, sliding instrument, polarized light microscopy and atomic absorption spectrophotometry. The statistical analysis of obtained data did not reveal significant differences for body weight, femoral weight, femoral length, and cortical bone thickness between both investigated groups of rats. However, a higher number of primary and secondary osteons was observed in the central area of substantia compacta and near periosteal surfaces in rats from the EG group. Histomorphometrical data of primary osteons' vascular canals, Haversian canals and secondary osteons did not differ between rats from both groups. Also, concentrations of Ca, Mg, Fe and Zn in the bones of rats from the EG group were similar to those from CG group. Our results indicate that 0.2% concentration of bee pollen in the diet significantly affects qualitative histological characteristics of femoral bones in rats. On the other hand, it has no impact on the size of primary and secondary osteons and on the content of Ca, Mg, Fe and Zn in the bones of male rats.