Quantitative and qualitative changes in endogenous nitrogen components along the small intestine of the calf
✍ Scribed by Lucile Montagne; René Toullec; Jean-Paul Lallès
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 169 KB
- Volume
- 80
- Category
- Article
- ISSN
- 0022-5142
No coin nor oath required. For personal study only.
✦ Synopsis
The aim of this study was to investigate the quantitative and qualitative changes in endogenous protein components along the calf's small intestine. A protein-free diet and three milk substitutes based on skim milk powder and differing in their protein level (100, 200 and 280 g kg À1 respectively) were prepared. Duodenal, jejunal and ileal digesta were collected through simple cannulae. The ¯ow of non-speci®c endogenous amino acids (AAs) determined with the protein-free diet was 8, 13 and 12 g kg À1 of dry matter intake in the duodenum, jejunum and ileum respectively. The ¯ow of endogenous amino acids in digesta from calves fed diets containing protein was determined using multiple linear regression analysis. It was higher than the non-speci®c ¯ow at the duodenum and jejunum owing to additional speci®c endogenous components. At the ileum, milk proteins were completely digested and the ¯ow of total AAs assayed was equal to the non-speci®c ¯ow. Seventy per cent of protein ¯owing at the jejunum was apparently reabsorbed before the terminal ileum. Endogenous protein at the duodenum resembled a theoretical mixture of proteins from saliva, gastric and pancreatic juices (140, 270 and 590 g kg À1 respectively). Ileal protein losses corresponded to a mixture of proteins from the host and gut bacteria in a 50:50 ratio. By contrast, no theoretical mixture of reference proteins ®tted the AA composition of jejunal endogenous protein.