In vitro evaluation of protein digestibility in the abomasum and small intestine of ruminants

Authors

• Jouko Setälä Valio Finnish Co-operative Dairies’ Association, Research and Development Department, P.O. Box 176, SF-00181 Helsinki, Finland
• Hanna Väätäinen Department of Animal Husbandry, University of Helsinki, SF-00710 Helsinki, Finland
• Terttu Ettala Valio Finnish Co-operative Dairies’ Association, Research and Development Department, P.O. Box 176, SF-00181 Helsinki, Finland

DOI: https://doi.org/10.23986/afsci.72166

Abstract

The investigation included studies with microbial protein, 0,5 % formaldehyde (HCHO) treated protein in soybean meal, and ruminally undegradable feed proteins in cotton seed and sunflower seed cakes. Microbial mass was separeted with centrifugations from the rumen contents of roughage-fed sheep. Undegradable feed proteins were prepared with the nylon bag technique. The proteins were digested in solutions of pepsin-HCI and trypsin-chymotrypsin. The average digestibility for microbial protein was 80.7 %. The corresponding values for the undegradable proteins in cottonseed cake and sunflower seed cake were 83.7 % and 82.7 %. In the incubation with pepsin-HCI, pH in the solution affected significantly (P < 0.001) the digestibility of HCHO-treated protein in soybean meal. The average digestibilities at pH 1.5—2.0, pH 2.5—3.0, and pH 3.1—4.0 were 97.2, 76.0, and 71.0 %, respectively.