Technical note: measuring portal blood flow in sheep using an ultrasonic transit time flow probe.

Rémond, Didier; Ortigues-Marty, I.; Isserty, A.; Lefaivre, J.

doi:10.2527/1998.76102712x

Cited by 18 publications

(11 citation statements)

References 14 publications

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“…In the relationships of PBF v. MEI (Ré mond et al (1998) and Bermingham et al (2008) in sheep, and Huntington (1990) in cattle), MEI (kJ/kg BW per day) ranges were comparable to those in the present study. In sheep, similar slopes were obtained in the present study compared with those of Ré mond et al (1998) with MEI above maintenance, and by Bermingham et al (2008) with DMI below and above maintenance. The slopes in sheep were lower than those in cattle (Huntington, 1990).…”

Section: Methodssupporting

confidence: 86%

Responses of hepatic blood flows to changes in intake in sheep: a meta-analysis

Vernet

Nozière²,

Léger³

et al. 2009

Animal

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This work set out to establish the response equations for hepatic blood flows in sheep and the contribution of hepatic arterial flow to hepatic venous blood flow due to changes in intake levels at constant diet composition. The FLORA (FLuxes across Organs and tissues in Ruminant Animals) database was used, and meta-analysis performed. The meta-analysis involved selection of published papers, identification of studies, description and coding of the selected dataset and statistical analysis using a covariance model. Meta-analyses were carried out using a within-study approach. To ensure absence of bias, the analysis incorporated interfering variables and factors studied in between-study comparisons. Variables concerned diet composition; qualitative factors concerned the physiological state of the animals and the methods used to measure blood flow. The results obtained showed that hepatic blood flows were positively related to intake in sheep. The magnitude of the response (as indicated by the slope) varied with the level of intake and the blood vessel (portal, hepatic venous or arterial). Nine linear relationships were established for the portal, hepatic venous and arterial blood flows as a function of dry matter intake (DMI) with below-and above-maintenance levels considered separately. Data obtained at below-and above-maintenance levels were considered together and four quadratic relationships were established for hepatic blood flows as a function of DMI. These relationships expressed a strong effect of intake on hepatic blood flows. The contribution of hepatic arterial to hepatic venous blood flow averaged 18.2%, with a wide variability. It did not vary significantly with level of intake. Although in between-study comparisons the arterial/venous blood flow was positively influenced by the organic matter digestibility of the diet, the relationships we obtained were robust. They can be used in models of net hepatic nutrient fluxes to predict variations and absolute values of hepatic blood flows from variations and absolute values of DMI.

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Section: Methodssupporting

confidence: 86%

Responses of hepatic blood flows to changes in intake in sheep: a meta-analysis

Vernet

Nozière²,

Léger³

et al. 2009

Animal

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“…The portal blood flow (PBF) recorded was consistent with the relationship observed in sheep between ME intake and PBF (Rémond et al 1998). The rumen and MDV blood flows observed in the present experiment accounted for 18 and 23 % of the PBF, respectively.…”

Section: Daily Net Fluxessupporting

confidence: 90%

Digestion and nutrient net fluxes across the rumen, and the mesenteric- and portal-drained viscera in sheep fed with fresh forage twice daily: net balance and dynamic aspects

et al. 2003

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Digestion and portal net flux of nutrients were studied in sheep fed twice daily with fresh orchard-grass. Digestive flows were measured in six fistulated sheep using the double-marker technique. Three sheep were fitted with catheters and blood-flow probes, allowing nutrient net flux measurements across the portal-drained viscera (PDV), the mesenteric-drained viscera (MDV) and the rumen. Total tract apparent digestion of N was similar to portal net appearance of N, calculated as the sum of free amino acids (FAA), peptide amino acids (PAA), NH 3 , and urea net fluxes. PAA accounted for 25 % of non-protein amino acid net release across the PDV. With the exception of glycine and glutamate, the small intestine was the main contributor to this PAA net release. The essential amino acid (EAA) apparent disappearance between the duodenum and the ileum was lower than the net appearance of EAA (FAA + PAA) across the MDV. The value of PDV:MDV flux of free EAA was, on average, 78 %. The rumen accounted for 30 % of the net uptake of EAA by the PDV tissues not drained by the mesenteric vein. Rumen net release of acetate, propionate, butyrate, 3-hydroxybutyrate, and lactate accounted for 70, 55, 46, 77 and 52 %, respectively, of their portal net releases. Conversely, the small intestine was a net consumer of arterial acetate and 3-hydroxybutyrate. Dynamic study of nutrient net fluxes across the PDV showed that throughout a feeding cycle, the liver faced a constant flux of amino acids (AA), whereas volatile fatty acid and NH 3 net fluxes varied in response to the meal. The present study specified, in forage-fed sheep, the partitioning of nutrient net fluxes across the PDV and the role of peptides in portal net release of AA.Amino acids: Volatile fatty acids: Absorption: Portal-drained viscera: SheepThe gastrointestinal tract, the interface between the diet and the animal, significantly modifies (quantitatively and qualitatively) the pattern of nutrients between the gut lumen and the bloodstream (Seal & Reynolds, 1993). In ruminants, although the portal-drained viscera (PDV) represent less than 10 % of body weight, and about 5 % of body protein mass, they account for one-quarter of total energy expenditure and one-third of total protein synthesis. This high metabolic activity of the gastrointestinal tract generates specific requirements in energy substrates and amino acids (AA). Thus, the portal appearance of volatile fatty acids (VFA), the main energy supply in ruminants, is lower than the amount produced in the gut, each of the individual VFA being metabolised to different extents by

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“…As previously reported (Huntington et al 1983;Gross et al 1990a,b;Krehbiel et al 1992;Seal & Parker, 1994;Kristensen et al 1996), portal blood flow was not modified by rumen infusion of SCFA. In conventionally-fed animals, it has been shown to vary positively with ME intake (for reviews see Huntington, 1990;Rémond et al 1998) but variations appear lower under v. above maintenance (Lomax & Baird, 1983;P. Nozière, D. Rémond, L. Bernard & M. Doreau, unpublished results).…”

Section: Portal Blood Flowmentioning

confidence: 99%

Effect of composition of ruminally-infused short-chain fatty acids on net fluxes of nutrients across portal-drained viscera in underfed ewes

et al. 2000

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Four ewes, each fitted with a rumen cannula and with catheters in the mesenteric artery and portal and mesenteric veins, received continuous intrarumen infusions of water or of short-chain fatty acids (SCFA). SCFA infusions were isoenergetic (83 kJ/h) and provided rumen molar proportions (acetate : propionate : butyrate) of 70 : 20 : 10, 50 : 40 : 10 or 50 : 20 : 30. The rumen SCFA production rate with the basal diet was 90·0, 23·1 and 8·8 mmol/h for acetate, propionate and butyrate respectively. Portal net fluxes indicated that 74, 67 and 22–30 % of infused acetate, propionate and butyrate respectively, reached the portal vein. Portal net release of β-hydroxybutyrate increased with SCFA infusions, irrespective of the amount of butyrate infused. Portal net release of lactate decreased with high-butyrate infusion. Portal net uptake of glucose increased with the SCFA infusions. In ewes infused with water, a portal net uptake of total amino acids (AA) was observed. SCFA infusions decreased the uptake of nonessential AA (glutamate, glycine, but not glutamine) and increased the net release of tyrosine and essential AA (isoleucine, leucine). Portal net fluxes of AA were similar with both high-acetate and high-propionate infusions. Lower net uptake of glutamine and net release of most essential AA and some nonessential AA were observed with the high-butyrate infusion. Energetic summation of portal net release was not significantly different between the three SCFA infusions, although it tended to be lower with high-butyrate infusion. This may be related to the higher trophic effect of butyrate on the digestive mucosa.

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Technical note: measuring portal blood flow in sheep using an ultrasonic transit time flow probe.

Cited by 18 publications

References 14 publications

Responses of hepatic blood flows to changes in intake in sheep: a meta-analysis

Responses of hepatic blood flows to changes in intake in sheep: a meta-analysis

Digestion and nutrient net fluxes across the rumen, and the mesenteric- and portal-drained viscera in sheep fed with fresh forage twice daily: net balance and dynamic aspects

Effect of composition of ruminally-infused short-chain fatty acids on net fluxes of nutrients across portal-drained viscera in underfed ewes

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