Endogenous amino acids at the terminal ileum of the adult human.

Author(s):  
P. J. Moughan
1988 ◽  
Vol 39 (4) ◽  
pp. 713 ◽  
Author(s):  
J Leibholz ◽  
Y Mollah

Six pigs (25 kg initial weight) were fitted with T cannulas in the terminal ileum. Each pig was fed a nitrogen (N) free diet or one of eight diets containing increasing amounts of threonine from milk (four diets) or cottonseed meal (four diets). The flow of endogenous nitrogen from the terminal ileum was 1.1 g/kg dry matter DM intake in the pigs given the nitrogen-free diet and 0.9 g/kg DM intake when estimated by extrapolation in the pigs given the milk or cottonseed meal diet. There were no significant differences in the flow of individual endogenous amino acids from the terminal ileum when measured in pigs given a nitrogen-free diet or when extrapolated from data for pigs given diets containing milk or cottonseed meal. The flow of endogenous threonine from the terminal ileum was between 0.39 and 0.45 g/kg DM intake as estimated in pigs given diets with similar threonine intakes from cottonseed meal or milk and the nitrogen-free diet.


1994 ◽  
Vol 71 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Angela M. Rowan ◽  
P. J. Moughan ◽  
M. N. Wilson ◽  
K. Maher ◽  
C. Tasman-Jones

The aim of the study was to determine if there is a difference between ileal and faecal assays for determining amino acid and N digestibilities in adult human subjects. Comparison of true ileal amino acid and N digestibilities was also made between adult human subjects and growing pigs to establish the usefulness of the pig as a model animal. Five subjects with established ileostomies and six subjects with intact large bowels consumed a constant diet consisting of meat, vegetables, fruit, bread and dairy products for 7 d with collection of ileostomy contents or faeces respectively over the last 4 d. The study was repeated using 25 kg body weight ileostomized and intact pigs. Apparent amino acid and N digestibility coefficients were determined. For human subjects the faecal digestibility values were significantly higher (P < 0·05) than the ileal values for Arg, Asp, Gly, Phe, Pro, Ser, Thr and Trp. The faecal digestibility of Met was significantly lower than the ileal value. Determination of DNA, diaminopimelic acid (DAPA) and the digestibilities of pectin, hemicellulose and cellulose in human subjects indicated that some microbial colonization had occurred at the terminal ileum after formation of an ileostomy; however, this was not as extensive as in the large intestine. True ileal amino acid and N digestibilities were calculated after correcting for the endogenous contribution of amino acids at the terminal ileum determined using a protein-free diet. There were no significant differences between adult human subjects and pigs for true ileal dietary amino acid digestibility except for Thr, Phe, Cys and Met. There were no significant differences between adult humans and pigs for the ileal digestibility of dry matter and the faecal digestibility of gross energy.


1984 ◽  
Vol 52 (2) ◽  
pp. 239-247 ◽  
Author(s):  
John R. Ashes ◽  
Jim L. Mangan ◽  
Gurcharn S. Sidhu

1. Casein was labelled with pairs of radioactive amino acids, lysine, tyrosine and leucine, one with I4C and the other with 3H, by jugular infusion into lactating goats followed by isolation of the double-labelled casein from the milk. Total milk protein was similarly labelled by jugular infusion of [35S]cystine. U-14C-labelled fraction- 1 leaf protein was isolated from lucerne (Medicago sativa) grown in an atmosphere of 14C022. The proteins were treated withdifferent levels(333 and667 mmol/kgprotein) offormaldehyde, glutaraldehyde and glyoxal.3. Absorption from the small intestine was measured in sheep with fistulas in the abomasum and terminal ileum, using Cr-EDTA as the digesta flow marker, by introducing radioactive casein into the abomasum.4. Lysine, tyrosine and cystine became increasingly unavailable for absorption from the small intestine of sheep with increasing levels of aldehyde. At the lower level (333 mmol/kg) the proportions of the amino acids that were unavailable were 0.192, 0.051 and 0.123 respectively. At the higher level of formaldehyde (667 mmol/kg) the corresponding values were 0.335, 0.201 and 0.432 respectively. Leucine was not made unavailable with formaldehyde.5. The proportions of lysine, tyrosine and leucine that were unavailable were higher, on a molar basis, after treatment of the proteins with the dialdehydes glutaraldehyde and glyoxal than after treatment with formaldehyde. However, the extent of protein protection provided by the dialdehydes in the rumen, measured using an in vitro procedure, was lower.


1987 ◽  
Vol 44 (2) ◽  
pp. 319-321 ◽  
Author(s):  
P. J. Moughan ◽  
W. C. Smith

Ileal digesta are often sampled from the pig through either re-entrant or simple T-piece cannulas. There is conflicting evidence, however, concerning the effects of cannulation on nutrient digestion and absorption. In several studies with the pig, cannulation has not influenced overall protein digestibility (Furuya, Takahashi and Omori, 1974; Sauer, Stothers and Parker, 1977; Taverner, 1979; Huisman, Weerden, Leeuwen, Hof and Sauer, 1984) or energy metabolism (Close, Heavens, Stephens and Sambrook, 1984) while in other studies (Laplace and Borgida, 1976; Sauer, Aherne and Thacker, 1979) there have been indications of adverse effects of cannulation on nutrient digestibility. Livingstone and McWilliam (1985) showed an effect of simple ileal cannulation on pig growth which may have been due to decreased nutrient digestibility or utilization.


1976 ◽  
Vol 23 (1) ◽  
pp. 111-119 ◽  
Author(s):  
M. Ivan ◽  
D. J. Farrell

SUMMARY1. Three pigs prepared with re-entrant cannulae in the proximal duodenum and terminal ileum were used to study flow rate of nitrogen, and digestion and absorption of dry matter, nitrogen, gross energy and starch. The pigs were given a semi-purified diet, a hard wheat diet and a soft wheat diet. These were approximately isonitrogenous.2. Nitrogen content of insoluble dry matter of duodenal digesta was much higher on the semi-purified diet than on the wheat-based diets.3. Apparent digestibilities of dry matter, energy and nitrogen in the small intestine were in the order semi-purified diet > hard wheat > soft wheat although differences were not statistically significant. Similar results were obtained for total digestibility of these components.4. Absorption of most amino acids from the small intestine was higher for casein in the semi-purified diet than for wheat protein. Significantly more lysine, arginine, isoleucine and tyrosine were absorbed from hard than from soft wheat.5. With all diets there was almost complete digestion of starch in the small intestine.6. There was little digestion of nutrients in the large intestine, and thus digestibilities calculated from faecal analyses showed similar trends to those calculated from analyses of digesta from the terminal ileum. Most values compared favourably with those reported elsewhere for digestibilities of amino acids in wheat.7. It was concluded that casein was superior to the wheat proteins but that protein of hard wheat was of better quality than that of soft wheat when evaluated by ileal recovery of animo acids, due largely to a greater absorption of lysine.


1970 ◽  
Vol 117 (5) ◽  
pp. 853-859 ◽  
Author(s):  
T. C. Hall ◽  
K. L. Tao

1. A procedure for measuring rates of aminoacyl-tRNA synthesis in vitro and in intact leaves is presented. 2. Leaf discs showed rates close to those of intact leaves. 3. Cell-free preparations showed similar rates when assayed by pyrophosphate exchange, but actual aminoacyl-tRNA formation rates appeared to be much lower. Evidence is presented that dilution of supplied labelled amino acids was a major factor causing the low apparent rates. 4. Attempts to strip endogenous amino acids from plant tRNA resulted in low acceptor capability of the tRNA.


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