Abstract
Nodules of the gut-associated lymphoid tissue (GALT) may be visualized and counted in acetic acid treated gastrointestinal tracts. The adult common toads Bufo bufo, soon after arousal from winter hibernation, were field-collected in the early spring and kept either in outdoor enclosure (mimicking the natural environment of this species) or in the laboratory at room temperature 22_C. Individuals kept in the laboratory were either fed ad libitum or starved. Their gastrointestinal tracts were treated with acetic acid which removes gut epithelium and exposes underlying structures facilitating macroscopic visualization and counting of GALT nodules. The number of GALT nodules in animals collected from natural conditions was negligible after winter hibernation, increased in the spring, reached the highest level in the summer and declined in the autumn. The vernal rebuilding of the GALT system occurred even in starved toads kept in the laboratory at room temperature but was significantly increased in their counterparts fed ad libitum.
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