Technical note: ruminal vein catheterization and continuous blood flow measurement in ruminal arteries of sheep1

Rémond, Didier; Poncet, C.; Lefaivre, J.

doi:10.2527/1993.7151276x

Cited by 21 publications

(28 citation statements)

References 9 publications

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“…This extraction rate decreased linearly with the increase in rumen ammonia concentration (r 2 = 0.44, n = 96). This negative relationship is in agreement with the observations of Rémond et al [13]. Since Houpt et Houpt [6] it is generally accepted that urea crosses the rumen epithelium by simple diffusion.…”

Section: Resultssupporting

confidence: 91%

“…They were fitted with a ruminal cannula, chronic indwelling catheters in the ruminal veins and in a mesenteric artery, and blood flow probes around the ruminal arteries [13]. Animals were allowed 1-month recovery from surgery before allocation to the trial.…”

Section: Animals and Dietmentioning

confidence: 99%

“…Blood flow (BF) was measured continuously with an ultrasonic transit time flowmeter (Transonic Systems, Ithaca, NY) interfaced with a computer for data acquisition [13].…”

Section: Sampling and Analysismentioning

confidence: 99%

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Effect of time of starch supply to the rumen on the dynamics of urea and ammonia net flux across the rumen wall of sheep

2002

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-The effects of rumen starch fermentation on urea and ammonia net fluxes across the ruminal wall were studied in four Texel wethers (67 ± 1.5 kg BW) fitted with catheters in both ruminal veins and in a mesenteric artery, blood flow probes on ruminal arteries, and a ruminal cannula. They were fed 500 g of orchardgrass hay every 12 h. A dose of 120 g of starch was added directly to the rumen either during the meal or 3 h later. On a daily basis, the time of starch supply did not modify the urea and ammonia net flux across the rumen wall. Within the feeding cycle, whatever the time of starch injection, the decrease in ruminal ammonia and pH and the increase in ruminal volatile fatty acids and CO 2 associated with starch fermentation were accompanied by a decrease in ammonia absorption and an increase in urea net transfer across the ruminal wall. This study confirms the existence of a synchronisation between urea net transfer across the rumen wall and rumen carbohydrate fermentation within a feeding cycle. Factors acting in the regulation of urea and ammonia net flux in the ruminal veins are discussed.

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Section: Resultssupporting

confidence: 91%

Section: Animals and Dietmentioning

confidence: 99%

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Effect of time of starch supply to the rumen on the dynamics of urea and ammonia net flux across the rumen wall of sheep

2002

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“…This is modified not only by factors that modify the blood flow rates at the wall, but also by electrolyte concentrations. The absorption of minerals from the rumen has also been demonstrated (Mg, Ca, Na, Cl, K, (Nolan and Leng, 1972), and the development of methods for ruminal blood flow measurement and ruminal vein catheterisation (Remond et al, 1993c), which make it possible to measure net fluxes of metabolites across the ruminal wall. The parallel use of in vitro techniques (Martens et al, 1978) According to Steven and Marshall (1970) Tamate, 1978, 1979 The inner surface area of the epithelium also varies according to the development of the mucosa .…”

mentioning

confidence: 99%

Metabolites, water and mineral exchanges across the rumen wall: mechanisms and regulation

Rémond¹,

Meschy²,

Boivin³

1996

Ann. Zootech.

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Summary — In ruminants, the forestomachs, and especially the reticulorumen, have walls with anatomical and histological properties that permit the exchanges of various metabolites, water and minerals between the rumen contents and the blood. The development of papillae on the walls and the local blood circulation favour these exchanges. They depend to varying degrees on the food supply and the concentrations of volatile fatty acids (VFA) produced by the microbial catabolism of polysaccharides. The absorption of VFA and ammonia occurs essentially by a process of passive diffusion of their nonionised form through the epithelial cell membranes. For each of these substances, the existence of a transport system for the ionised forms is also suspected, but its relative importance is unknown. Shortterm modifications in the absorption of these two substances are thus primarily determined by variations in their intraruminal concentrations and pH. Other factors may also be implicated, and it is known in particular that the absorption of ammonia is enhanced when the intraruminal concentration of VFA or the carbon dioxide (C0 2 ) level increases. The movement of urea through the wall occurs from the blood towards the rumen content according to the concentration gradient. The main factors liable to influence the transepithelial flux of urea seem to be the blood urea levels and factors that act on the contact surface between the blood compartment and the epithelium (C0 2 , VFA). Ruminal ammonia concentration also affects the net urea transfer across the rumen wall but the mechanisms involved in this regulation are not clearly understood. The absorption of water through the rumen wall results from an osmotic pressure gradient between the rumen and the plasma. This is modified not only by factors that modify the blood flow rates at the wall, but also by electrolyte concentrations. The absorption of minerals from the rumen has also been demonstrated (Mg, Ca, Na, Cl, K,

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“…The perivascular probes used (R-series, 3 mm) were placed around the two ruminal arteries according to the technique described by Remond et al (1993), carried out under halothane (0·5-2·0%) in oxygen (6 l min¢) anaesthesia. After recovery, the sheep were housed in individual pens in a temperature-controlled room (18-22°C) with a natural lighting cycle.…”

mentioning

confidence: 99%

The Relaxant Effects of Parathyroid Hormone(1‐34) and Parathyroid Hormone‐Related Protein(1‐34) on Ovine Reticulo‐Ruminal Smooth Muscle in Vivo

Care

Abbas

Harmeyer

et al. 1999

Experimental Physiology

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summaryThe motility of the reticulo-rumen has been measured in trained, conscious sheep using inflated balloons temporarily introduced to selected regions of that forestomach. The frequency and amplitude of the contractions of the reticulum and both the A and B waves of contraction of the rumen were measured under the same conditions before, during and after the administration of an i.v. bolus of either parathyroid hormone (PTH(1-34)) or PTH-related protein (PTHrP(1-34)) followed by its i.v. infusion. These two peptides are known to share a common receptor in other organs, e.g. the kidney. In this study they both showed an inhibitory effect on reticulo-ruminal motility. The effect of PTHrP(1-34) on the rate of ruminal blood flow was also examined and a significant reduction observed, after a transient increase. The secretion of endogenous PTH(1-34) was stimulated by a 32% reduction in the plasma calcium ion concentration induced by an i.v. infusion of sodium citrate. Associated with this were significant reductions in reticulo-ruminal motility, e.g. the reduction in the mean amplitude of the reticular contractions reflected the reduction in plasma calcium ion concentration. ]PTHrP(7-34) before and during the induction of hypocalcaemia, all but one of the parameters of reticulo-ruminal motility were normalized. Indeed, by the day following the administration of this blocking agent, all these parameters had returned to their normal range. It is concluded that stimulation of the PTH(1-34)ÏPTHrP(1-34) receptor in reticulo-ruminal smooth muscle reduces the motility of this tissue and may play a role in the depression of motility of the digestive tract which is characteristic of clinical milk fever in the dairy cow. introduction Although ruminants largely depend upon the enteric nervous system for the reflex control of mixing contractions in the reticulo-rumen, endocrine influences are also involved. One of these is shown here to be parathyroid hormone-related protein (PTHrP (1-34)) which has been demonstrated to share a receptor on both osteoblasts and renal distal tubules with PTH(1-34) (Nissenson et al. 1988) and also on rat fundic strips (Mok et al. 1989). Another is gastrin which acts both centrally and peripherally to reduce the motility of the reticulum (Grovum, 1986).Although not yet studied in sheep, the expression o PTHrP in the stomach of the rat has been shown to be induced by mechanical stretch (Cooper et al. 1991) and also by contractions induced by carbachol (Ito et al. 1994). Moreover, from in vitro experiments using fundic strips of rat stomach, it has been shown that the addition of PTHrP(1-34) significantly reduces

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Technical note: ruminal vein catheterization and continuous blood flow measurement in ruminal arteries of sheep1

Cited by 21 publications

References 9 publications

Effect of time of starch supply to the rumen on the dynamics of urea and ammonia net flux across the rumen wall of sheep

Effect of time of starch supply to the rumen on the dynamics of urea and ammonia net flux across the rumen wall of sheep

Metabolites, water and mineral exchanges across the rumen wall: mechanisms and regulation

The Relaxant Effects of Parathyroid Hormone(1‐34) and Parathyroid Hormone‐Related Protein(1‐34) on Ovine Reticulo‐Ruminal Smooth Muscle in Vivo

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