Zur Kenntnis von Bau und Funktion des Magens der Schlankaffen (Colobinae)

Abstract

The structure and function of the stomach of the Colobinae was studied in the 3 Liberian species Colobus p. polykomos, Procolobus b. badlus and Procolobus versus. Free Colobus polykomos and Procolobus versus eat mainly leaves, Procolobus badlus takes in a considerable amount of the fruits of Legumlnosae in addition. The food is chewed into very fine particles and fermented in the 2 voluminous 1st parts of the stomach of Procolobus by bacteria. Besides volatile fatty acids, CO2 and methane are produced during this process. The pH is around 7. In Colobus polykomos and Presbytis cristatus the division separating praesaccus and saccus gastricus, the 2 first parts of the stomach, is hardly developed. The wall of praesaccus and saccus gastricus is characterized by a surface epithelium and glands producing large amounts of mucus, by numerous lymphatic follicles and diffuse round cell infiltration of the lamina propria mucosae and by the "colon-like" structure of the tunica muscularis. No ciliates were found, but nematodes occur regularly in the 1st 2 parts of the stomach. Principal glands are found in the 2nd half of the narrow tubus gastricus (the 3rd part of the stomach) where the pH goes down below 3. The last part, the pars pylorica, is coated by a mucosa containing typical pyloric glands. The possible role of the fermentation for the energy requirements of the Colobinae is briefly discussed.