Abstract
The aim of this investigations was to assess morphological changes in the midgut epithelium of bees nourished with pollen substitute or pollen substitute enriched with a probiotic preparation. One-day old worker bees were kept in cages placed in a temperature controlled environment. During the two-week feeding period workers were fed beebread (control), pure pollen substitute or pollen substitute fortified with three different doses of probiotic preparations: Biogen or Trilac (experimental groups). The assessment of histological changes of the bee midgut was carried out in bees feed for 8 and 14 days. Slight changes in the epithelium as well as strong merocrine-type secretion were recorded in bees nourished pollen substitute supplemented with probiotic preparations. Differences were observed, primarily, in quantities of the developed peritrophic membranes. Their quantities were particularly high after 14 days of feeding with the pollen substitute fortified with probiotic preparations. The development of numerous peritrophic membranes could have contributed to better utilization of nutrients contained in feed and better condition of bees.