The digestion of protein from forage diets in the small intestine of the sheep

Lindsay, JR; Hogan, JP; Donnelly, J. B.

doi:10.1071/ar9800589

Cited by 23 publications

(16 citation statements)

References 27 publications

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“…However, as the absorption of exogenous protein is not affected by parasitism then the increased flow of NAN at the ileum presumably represents endogenous amino acids, mostly epithelial cells and mucus protein. Mucus secretions are high in S amino acids, threonine and histidine (Clarke et al 1966;Lindsay et al 1980;Steel & Symons, 1982) and this could result in a loss of these essential amino acids through incomplete resorption.…”

Section: Discussionmentioning

confidence: 99%

“…This would require that the remainder of the extra ileal NAN (0.3 g NAN/d during weeks 5-7; 2.3 g NAN/d during weeks 11-13) arises from other endogenous secretions, perhaps either mucins or sloughed cells, or both. Lindsay et al (1980) suggested that theresorption of totalendogenous proteininnormal animalsmay be as highas 0.85-0.90. If, therefore, a similar value were applicable to the infected lambs this would require that during weeks 5-7 and 1 1-13 of dosing an extra 3-5 g NAN and 1 4 2 1 g NAN/d be secreted into the small intestine to account for the extra non-resorbed endogenous component at the ileum.…”

Section: Discussionmentioning

confidence: 99%

“…Even with a resorption factor similar to the true digestibility of 35S-labelled bacterial protein (0.7), the increased endogenous secretions would still amount to 1.7 g NAN/d during weeks 5-7 of dosing and 7 g NAN/d during weeks 11-1 3 of dosing. Lindsay et al (1980) have suggested that the amount of endogenous protein-N added to the small intestines of normal animals is approximately 15 g N/d. If this is so then parasitism appears to increase endogenous protein secretion losses by 0.38-1.5 depending on the resorption coefficient used.…”

Section: Discussionmentioning

confidence: 99%

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Nitrogen transactions in the digestive tract of lambs exposed to the intestinal parasite, Trichostrongylus colubriformis

Poppi¹,

MacRae²,

Brewer³

et al. 1986

Br J Nutr

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1.Ten 5-month-old lambs (29 (SE 1.2) kg), reared parasite-free and prepared with rumen duodenal and ileal cannulas, were paired and given rations of Ruminant Diet AA6 (90 g/kg live by means of continuous feeders. From 6 months of age one of each pair was dosed daily with 2500 Trichostrongylus colubriformis larvae for 14 weeks. Untreated animals received the amount of ration consumed by their infected pair-mates the previous day.2. During three periods, ((1) the week before and the first 2 weeks of dosing with infected larvae, (2) during weeks 5-7 and (3) during weeks 11-13 of dosing) all lambs underwent a series of experiments to determine their nitrogen balance, the amounts of N leaving the small intestine, the amount of 5'CrC1,-labelled plasma protein leaking into the small intestines, and the disappearance of 35S-labelled bacteria from the small intestine.3. The infection caused varying degrees of feed refusal in all infected animals. As a result the values for N balance and for the flow of N at the ileum during the latter two periods were regressed against dry-matter intakes for each group in each period.4. The infection caused a reduction ( P < 0.05) in N retention and increased ( P < 0.05) flow of N at the ileum. The increase in N flow at the ileum of infected lambs was greater ( P < 0.01) at weeks 11-13 of dosing (infected-control 3.6 g N/d (standard error of difference (SED) 0.57), P < 0.01) than at weeks 5-7 of dosing (infected -control 1.5 g N/d (SED 0.57), P < 0.05).5. There were no between-treatment or between-period differences in the disappearance of 35S-labelled bacteria from the small intestines of infected or control lambs, but the infection did cause an increase in plasma N leakage during both periods. During weeks 5-7 and 11-13, plasma N leakage in infected lambs was 1.1 g N/d ( P < 0.01) and 1.7 g N/d (P = 0.056) respectively higher than that in the control lambs.6. A proportion of the endogenous secretions which enter the small intestine is likely to be resorbed before the ileum. It was calculated that to account for the extra non-ammonia-N (NAN) flow at the ileum up to 3-5 g NAN/d during weeks 5-7 of dosing and 15-20 g N/d during weeks 11-13 of dosing could have entered the small intestine as mucin and sloughed cells.7. The results seem to indicate that the nutritional penalty associated with the development of resistance to infection is greater than that associated with the primary infection.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Nitrogen transactions in the digestive tract of lambs exposed to the intestinal parasite, Trichostrongylus colubriformis

Poppi¹,

MacRae²,

Brewer³

et al. 1986

Br J Nutr

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“…Thus, any elevation in digestive secretion losses will decrease the availability of these amino acids for protein synthesis and gain in other tissues. Most serious is the high concentration of threonine (280 mmoVmol), serine (130 mmoVmo1) and proline (130 mrnoUmol) in intestinal mucus (Neutra & Forstner, 1987), which is reported to be resistant to proteolytic degradation and poorly resorbed from the small intestine (Lindsay et al 1980). Another implication of the immunological resistance phase of infection relates to the availability of sulphur-amino acids for leukotriene production (Lewis & Austen, 1981).…”

Section: Consequences Of Infection O N T H E Availability Of I N D I mentioning

confidence: 99%

Metabolic consequences of intestinal parasitism

MacRae¹

1993

Proc. Nutr. Soc.

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“…Additionally, mucus has been reported to be resistant to digestion and resorption from the small intestine (Lindsay et al, 1980). When mucus is formed, its component amino acids are effectively unavailable for reuse in synthesis of other proteins (Knox et al, 2006).…”

Section: Nutrient Metabolismmentioning

confidence: 99%

Effects of dietary protein supplementation and plane of nutrition on the resistance and the resilience of Boer goats against artificial Haemonchus contortus infection under confined conditions

Can¹

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The effects of protein and/ or energy supplementation have been well studied in sheep. However, the few pen studies conducted with goats have failed to identify the role of protein supplementation and combinations with energy supplements against H. contortus infection.The general objective of this thesis was to investigate the effects of protein supplementation and plane of nutrition on resistance and resilience of Boer goats to infection from Haemonchus contortus. To achieve this the first experiment was designed to determine the appropriate amount of additional dietary protein (by having three groups of mature goats effectively fed three different levels of dietary protein) required by nematode free animals given a single relatively high dose of infective H. contortus larvae, to not become infected or at least develop resistance and/or resilience. It was assumed, based on the scientific literature, that a single relatively high dose of infective larvae would elicit strong pathogenic effects where additional dietary protein would give some assistance to the does with their defense to Haemonchus. As often is the case with research on goats the results were not unequivocally clear.Based on these results it was clear that a single dose of infective larvae was insufficient to become established and that these animals had already developed some level of immune response and thus it was assumed, again based on the scientific literature, to elicit strong pathogenic effects the animals tested needed to be younger (more naïve to Haemonchus) and with greater i.e. continued exposure to infective larvae as would happen under grazing conditions (trickle infection) such that different quantities of dietary protein would give these animals different responses to infection by Haemonchus. Again the responses by the goats only indicated subtle differences in immune responses against trickle H. contortus L3 infection. These results, again unexpected, indicated that level of intake (or more specifically plane of nutrition, prior to or during exposure) may be at least as important as protein supplementation in reasonably well fed animals; and or that the method of infection (oral drenching with L3 larvae) was possibly an unreliable method of infection requiring a more consistent method of infection. As such the third experiment involved nematode free mature animals (the only animals available at that time) fed on very different planes of nutrition preceding and during the experiment given relatively high trickle doses of H. contortus larvae via intra-ruminal infection.Overlaid across these experiments were constraints imposed on the amount of infective L3 larvae used to achieve infection; 100 L3 larvae per kg live-weight as a single dose was the maximum initially approved by the University Animal Ethics committee, as they had concerns about animals dying, they also stipulated the use of oral drenching for infective larvae. It was only after these methods failed ii to elicit a strong response was approval given by the Univers...

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The digestion of protein from forage diets in the small intestine of the sheep

Cited by 23 publications

References 27 publications

Nitrogen transactions in the digestive tract of lambs exposed to the intestinal parasite, Trichostrongylus colubriformis

Nitrogen transactions in the digestive tract of lambs exposed to the intestinal parasite, Trichostrongylus colubriformis

Metabolic consequences of intestinal parasitism

Effects of dietary protein supplementation and plane of nutrition on the resistance and the resilience of Boer goats against artificial Haemonchus contortus infection under confined conditions

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