The digestion of dietary protein bound by condensed tannins in the gastro-intestinal tract of sheep

• Published in: Animal feed science and technology Vol. 142; no. 3; pp. 197 - 209
• Main Authors: Kariuki, I.W., Norton, B.W.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2008; [New York, NY]: Elsevier Science; Elsevier
• Subjects: 125I-BSA; 51Cr-EDTA; abomasum; Animal productions; Biological and medical sciences; Condensed tannin; dietary protein; digestion; Feed and pet food industries; feed quality; fistula; Food industries; Fundamental and applied biological sciences. Psychology; Gastro-intestinal tract; gastrointestinal system; intraruminal administration; iodinated bovine serum albumin; Leucaena pallida; metabolic studies; proanthocyanidins; Protein; radionuclides; ruminant nutrition; sheep; sheep feeding; Terrestrial animal productions; True digestibility; Vertebrates; CT; GIT; 125I-BSA; Condensed tannin; True digestibility; 51Cr-EDTA; Gastro-intestinal tract; Protein; Farming animal; Digestion; EDTA; Flavonoid; Vertebrata; Polyphenol; Meat animals; Mammalia; Tannin; Sheep; Artiodactyla; Ungulata; Digestibility
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2007.08.006

The digestion of dietary protein bound by condensed tannins (CTs) in ruminants was investigated by determining the extent of dissociation of insoluble 125I-BSA + CT complexes administered to abomasally and intestinally fistulated sheep. The extent of dissociation was registered as the true digestibility of iodinated bovine serum albumin ( 125I-BSA). The true digestibility of 125I-BSA originally bound to Leucaena pallida CT (0.721) was lower (P<0.05) than that of 125I-BSA originally bound to L. leucocephala CT (0.880) between the abomasum and terminal ileum. These results indicate that differences in the ability of CT to inhibit 125I-BSA digestion in vivo matched the relative abilities of the same CT to bind BSA in vitro, indicating that the in vitro BSA-binding assay for ranking CT behaviour was biologically relevant in vivo. Furthermore, the true digestibility of CT-bound 125I-BSA between the mouth and faeces permitted the prediction of the quantitative contribution that CT-bound dietary proteins make to improved nitrogen supply to the small intestines.