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

Rémond, Didier; Nozière, Pierre; Poncet, C.

doi:10.1051/animres:2002002

Cited by 12 publications

(7 citation statements)

References 14 publications

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“…These results are similar to the results from previous studies in rats and rabbits (Tokunaga et al 1989;Oku 1996;Xiao et al 2012). Both in vivo Thorlacius et al 1971;Remond et al 1993Remond et al , 2002von Engelhardt et al 2007) and in vitro (Abdoun et al 2005) studies of the ruminal epithelium suggested SCFA and CO 2 facilitate the transport of urea into the rumen. SCFA might have facilitated the transport of blood urea N into the cecum of the guinea pigs; similar to what has been observed in ruminants.…”

Section: Discussionsupporting

confidence: 90%

Transfer of blood urea nitrogen to cecal microbial nitrogen is increased by fructo‐oligosaccharide feeding in guinea pigs

Kawasaki

Xiao

et al. 2014

Animal Science Journal

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The present study was conducted to determine the mechanism by which nitrogen (N) availability is improved by fructo-oligosaccharide (FOS) in guinea pigs. Adult male guinea pigs were fed a commercial pellet diet (50 g/day) with either 5% glucose or 5% FOS for 7 days in individual metabolism cages. After 7 days of feeding the diet, (15) N-urea was administered intravenously 1 h before slaughter under anesthesia. The amount and concentration of total, protein, bacterial, ammonia and urea N and the (15) N atom % excess were measured in blood, liver, gut contents and urine. The (15) N atom % excess of total and protein N, and the amount of total, protein and bacteria N and (15) N in the cecum were significantly increased by the consumption of FOS. Furthermore, the concentration and amount of short-chain fatty acids were significantly increased by the consumption of FOS. In contrast, the amount of urinary (15) N was significantly decreased by the consumption of FOS. These results suggest that consumption of FOS increases transfer of blood urea N into the large intestine for bacterial N synthesis, which is subsequently re-absorbed by cecotrophy, and contributes to the increase of N utilization in guinea pigs.

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Section: Discussionsupporting

confidence: 90%

Transfer of blood urea nitrogen to cecal microbial nitrogen is increased by fructo‐oligosaccharide feeding in guinea pigs

Kawasaki

Xiao

et al. 2014

Animal Science Journal

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“…This is a typical pattern for ruminal NH3-N rumen pool. It fits the model which usually peaks after feeding followed by a decrease in NH3-N and pH, increase in ruminal VFA and CO2 associated with starch fermentation, accompanied by a decrease in NH3 absorption and a later increase in urea transfer across the ruminal wall (Rémond et al, 2002;Abdoun et al, 2006). The consistently lower NH3-N concentration 2 h after feeding can be linked to the negative DIP balance for CD.…”

Section: Blood Profile and Rumen Parameterssupporting

confidence: 61%

Performance and ultrasound measurements of beef cattle fed diets based on whole corn or oats grains

Arelovich

Bravo

Martínez

et al. 2013

Chilean J. Agric. Res.

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This study intended to contrast dietary effects of whole grain oats versus corn included in rations with moderate roughage content on animal performance, beef ultrasound measurements, rumen and blood parameters. Ten Aberdeen Angus steers (203 kg) in individual pens were fed twice daily on either whole oats (OD) or corn (CD) based diets. Measurements were: DM intake (DMI), average daily gain (ADG), feed to gain ratio (F/G); back fat (BF) and rib eye area (RA); blood parameters. Four cannulated steers were used to study rumen pH, NH3-N and grain degradability. Rations dietary components were 55% grain, 30.1% barley straw, and 10.6% whole soybeans. Despite calculated higher ME supply (P = 0.0887) no differences were found for DMI, ADG, or F/G. Metabolizable protein intake (19.4%) was larger and degradable protein intake (43.3%) smaller for CD compared with OD (P < 0.01). The growth rate (cm 2 d -1) for RA was 40% grater for OD, but larger BF deposition (P = 0.0787) was found for CD. Blood Mg was higher for OD (p = 0.0564), nevertheless other blood parameters remained unaffected. Rumen pH and NH3-N were not influenced by diet, variations were only observed within time periods. Rumen pH decreased linearly from 7.05 to 6.13 and 7.11 to 6.37 for OD and CD respectively (P < 0.05). Minimum NH3-N concentrations (mg dL -1 ) were reached 12 and 18 h after morning meal for OD (7.10) and CD (5.82) respectively. Rumen degradation was larger for oats than corn. Whole oats rather than corn fed up to 55% of total DM seems to improve protein deposition, without significant changes in animal performance, rumen environment or blood parameters.

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“…The mechanism by which epithelial urea flux is regulated is unknown at present. However, it has been shown that timing of starch feeding relative to roughage feeding affects the ruminal vein extraction of urea (Ré mond et al, 2002). This points to epithelial blood flow as a possible determinant of urea extraction across PDV tissues, because it is only blood passing the epithelia that supply urea to the gastro-intestinal tract.…”

Section: Net Portal Fluxesmentioning

confidence: 99%

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

Røjen

Lund

Kristensen

2008

Animal

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Three ruminally cannulated and multicatheterised lactating dairy cows were used to investigate the effect of different supplement strategies to fresh clover grass on urea and short-chain fatty acid (SCFA) metabolism in a zero-grazing experiment with 24-h blood and ruminal samplings. Fresh clover grass was cut every morning and offered from 0800 to 1500 h. Maize silage was fed at 1530 h. The three treatments, arranged in a Latin square, differed by timing of feeding rolled barley and soya-bean hulls relative to fresh clover grass. All diets had the same overall composition. Treatments were soya-bean hulls fed at 0700 h and barley fed at 1530 h (SAM), barley fed at 0700 h and soya-bean hulls fed at 1530 h (BAM), and both soya-bean hulls and barley fed at 1530 h (SBPM). The grass had an unexpectedly low content of crude protein (12.7%) and the cows were severely undersupplied with rumen degradable protein. The treatment effects were numerically small; greater arterial ammonia concentration, net portal flux of ammonia and net hepatic flux of urea during part of the day were observed when no supplementary carbohydrate was fed before grass feeding. A marked diurnal variation in ruminal fermentation was observed and grass feeding increased ruminal concentrations of propionate and butyrate. The net portal fluxes of propionate, butyrate, isovalerate and valerate as well as the net hepatic uptake of propionate, butyrate, valerate and caproate increased after feeding at 0700 h. The hepatic extraction of butyrate showed a relatively large depression with grass feeding with nadir at 1200 to 1330 h. The increased net portal absorption and the decreased hepatic extraction resulted in an approximately six-fold increase in the arterial blood concentration of butyrate. The gut entry rate of urea accounted for 70 6 10% of the net hepatic production of urea. Saliva contributed to 14% of the total amount of urea recycled to the gut. Urea recycling to the gut was equivalent to 58% of the dietary nitrogen intake. Despite the severe undersupply of rumen degradable protein, the portaldrained viscera did not extract more than 4.3% of the urea supplied with arterial blood. This value is in line with the literature values for cows fed diets only moderately deficient in rumen degradable protein and indicates that cows maximise urea transfer across gut epithelia even when the diet is moderately deficient in rumen degradable protein.

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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

Cited by 12 publications

References 14 publications

Transfer of blood urea nitrogen to cecal microbial nitrogen is increased by fructo‐oligosaccharide feeding in guinea pigs

Transfer of blood urea nitrogen to cecal microbial nitrogen is increased by fructo‐oligosaccharide feeding in guinea pigs

Performance and ultrasound measurements of beef cattle fed diets based on whole corn or oats grains

Urea and short-chain fatty acids metabolism in Holstein cows fed a low-nitrogen grass-based diet

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