Pavel Dobeš 1, Libor Vojtek 1, Zuzana Hroncová 2, Jan Tyl 3, Jiří Killer 4,
Peter Černoch 5, Pavel Hyršl 1
Honey bee immunity:
Its modulation by dietary supplements and probiotics
Our research is supported by research grants from Ministry of Agriculture of Czech Republic
(NAZV-KUS QJ1210047) and Technology Agency of Czech Republic (TA04020318).
Bees are used by mankind for several thousand years, but their immune system is still far from
being fully understood and moreover we still do not have clear idea about all immune mechanisms,
which mediate bees’ response to the pathogens. The immune system of honey bees can be divided to
cellular and humoral branch that are complemented by highly developed social behaviour. Detailed
knowledge of bee immunity is crucial for successful fight against bee diseases.
Honeybee immunity
Contact e-mail: pavel.dobes@mail.muni.cz
Applied dietary supplements and experimental design
§effect of location (different food sources)
§effect of dietary supplements:
extracts from Echinacea sp. (Fig. 1)
extracts from Leuzea sp. (Fig. 2)
alkaloid sanguinarine from Macleaya cordata (Fig. 3)
probiotic bacteria Lactobacillus apis
probiotic bacteria Lactobacillus melliventris
probiotic bacteria Gilliamella apicola
mixture of probiotic bacteria (Fig. 4)
For several years we follow immunocompetence of honey bees from selected beehives located in
different parts of Czech Republic. All locations offer unique source of nutrients and were included
to describe variability of followed parameters dependent on environment.
We tried to increase immunocompetence of bees by feeding them with selected plant extracts (in
dilutions 10x and 100x), plant alkaloid sanguinarine and by administration of probiotic bacterial
strains isolated from gut of honey bees. Probiotics and plant extracs were sprayed on experimental
combs (Fig. 4) and sanguinarine was administered in sucrose syrup (Fig. 5).
Bees were sampled in selected days before and after experimental treatment (Fig. 6). Haemolymph
samples were collected from staged honey bee larvae (Fig. 7) and adult workers (Fig. 8). Date of
haemolymph collection was recorded for further analysis of seasonal effect on immune parameters.
We followed several physiological and immune parameters including protein concentration,
antimicrobial activity, phenoloxidase activity    and antioxidant capacity of haemolymph. Analysis
and statistical evaluation are still in progress.
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Results
Influence of plant alkaloid sanguinarine on total protein level (left) and antimicrobial activity
towards Micrococcus luteus (right) in haemolymph of honey bee larvae.
Time after infection
Time after infection
Survival of honey bee larvae infected with entomopathogenic nematode Steinernema feltiae (left)
                  or Heterorhabditis bacteriophora (right). Bees were treated with the mixture of
probiotic bacteria and plant alkaloid sanguinarine. The survival of honey bee larvae were followed
for three days upon infection.
Influence of probiotics on total protein level (left) and antimicrobial activity towards
Micrococcus luteus (right)    in haemolymph of honey bee larvae.
Effect of plant extracts from Echinacea sp. (ECHI) and Leuzea sp. (MAR) on total protein
concentration in haemolymph (left) and antimicrobial activity towards Micrococcus luteus (right).
Plant extracts were prepared in two dilutions of acetone (80%          and 100%) and administered
to the bees in two different dilutions (10x and 100x).
Differences in total antioxidant capacity of honey bee haemolymph observed among particular beehive
locations (marked by numbers and shown on the map above) involved          in experiment. Data from
three different sample collections are shown.
Conclusions
§higher concentrations of Echinacea extracts are negatively correlated with antimicrobial activity
towards gram-positive bacteria in haemolymph of honey bee larvae; the effect on activity against
gram-negative bacteria is not known yet
§lower sanguinarine concentration can prevent bee larvae from fluctuation in antimicrobial activity
§probiotics can have positive influence on survival during natural infections as demonstrated by
experimental infection of honey bee larvae with entomopathogenic nematodes