Histochemistry of the forestomach epithelium of the reindeer calf

Samples from the rumen, reticulum and omasum of 26 reindeer calves were taken during the winter season. Non-specific alkaline and acid phosphatases, cytochrome and amine oxidases as well as succinate, lactate and 3-hydroxybutyrate dehydrogenases were demonstrated in the epithelium histochemically. The phosphatases were usually present in all the epithelial layers, whereas the activities of the other enzymes decreased in the outer layers and could not be demonstrated in the stratum corneum. The activity of alkaline phosphatase seemed to be highest in the reticulum and lowest in the omasum. The reason for the higher activity of this enzyme in epithelial taps in the rumen and omasum and in the reticular and omasal papillae may be the greater need for effective vertical transcellular transport in these regions. There was a tendency for enzymes other than phosphatases to be more active in the rumen than in the other forestomachs, which probably reflects the higher metabolic activity of the ruminal epithelium. No clear differences between early and late winter could be demonstrated.