1. *Institute of Biology, University of Warsaw, Branch in Białystok,15–950 Białystok, Świerkowa 20B Str. P.O. Box 109, Poland
2. **The Swedish University of Agricultural Sciences, Department of Animal Physiology, S‐75007 Uppsala, Sweden
3. ***Institute of Environmental Biology, Jagiellonian University,30–063 KrakóAw, Oleandry 2a, Poland