Acute effects on hypertonicity on the potential difference across the rumen wall in sheep

Flow of nitrogen from the rumen and abomasum in cattle and sheep given protein-free nutrients by intragastric infusion

“…When rumen OP were in excess of about 330 mosmol/l there was a net increase in liquid outflow from the rumen, but when the OP was lower there was an associated decrease in liquid outflow. This observation is in agreement with the results of Stacy & Warner (1972), showing that at or aboQt 350 mosmol/l there was a decrease in absorption rate of sodium and movement of water from the blood to the rumen. PEG or CrEDTA as markers.…”

Flow of nitrogen from the rumen and abomasum in cattle and sheep given protein-free nutrients by intragastric infusion

“…When rumen OP were in excess of about 330 mosmol/l there was a net increase in liquid outflow from the rumen, but when the OP was lower there was an associated decrease in liquid outflow. This observation is in agreement with the results of Stacy & Warner (1972), showing that at or aboQt 350 mosmol/l there was a decrease in absorption rate of sodium and movement of water from the blood to the rumen. PEG or CrEDTA as markers.…”

A review of the physiological significance of hypertonic body fluids on feed intake and ruminal function: salivation, motility and microbes.

“…Stimulation of Na+ absorption by raising the K+ concentration in the rumen has been demonstrated in other studies (Stacy and Warner, 1%6;Scott, 1967;Warner and Stacy, 1972). However, osmotic pressure per se still was thought to be a significant factor contributing to Na+ absorption from the rumen (Warner and Stacy, 1972). More recently, Gaebel et al (1987) concluded that raising the tonicity of artificial ruminal fluid in sheep to 422 mOsmowter with mannitol did not affect the net absorption rate of Na+, C1-or Mg*.…”

“…This increased absorption occurred provided that water entry into the rumen was minimal. However, when there was substantial movement of water into the rumen (e.g., 70 to 290 mVh, at ruminal osmolalities greater than 400 mOsmoVkg), Na+ absorption appeared to decrease (Warner and Stacy, 1972). The unchanged Na+ absorption observed in the study by Gaebel et al (1987) was associated with a net water flow into the rumen of 65 to 98 mljh.…”

“…Although the concentration of Na+ in the ruminal fluid of cows fed a variety of diets was lower than that of saliva (Bailey, 1961a), Na+ was the principal cation of ruminal fluid from cattle fed various diets with values from 74.5 to 157.8 meq/liter (Ward et al, 1976). Stacy and Warner (1966) calculated that increasing the tonicity of ruminal fluid in sheep led to an increase in the absorption rate of Na+, although the increase was small when tonicity was raised with nonionic sources (mannitol plus urea or glycerol) compared with potassium as KCl or K+ salts of the W A (Warner and Stacy, 1972). Stimulation of Na+ absorption by raising the K+ concentration in the rumen has been demonstrated in other studies (Stacy and Warner, 1%6;Scott, 1967;Warner and Stacy, 1972).…”

“…There was no change in the F' D across the ruminal epithelium in the studies in which the tonicity of artificial ruminal fluid was raised to 422 mOsmoVliter (Gaebel et al, 1987). When KC1 was added to the rumen to elevate the tonicity to 367 mOsmoVkg, the PD increased, but when further KC1 was added to raise tonicity to 526 mOsmol/kg, the PD dropped to a level below that for the resting tonicity (Stacy and Warner, 1972). The decrease in PD at very high tonicities, which was replicated with glycerol, was interpreted as being due to an increase in passive diffusion of water and Na+ from the blood into the rumen.…”

Flow of nitrogen from the rumen and abomasum in cattle and sheep given protein-free nutrients by intragastric infusion

“…When rumen OP were in excess of about 330 mosmol/l there was a net increase in liquid outflow from the rumen, but when the OP was lower there was an associated decrease in liquid outflow. This observation is in agreement with the results of Stacy & Warner (1972), showing that at or aboQt 350 mosmol/l there was a decrease in absorption rate of sodium and movement of water from the blood to the rumen. PEG or CrEDTA as markers.…”

A review of the physiological significance of hypertonic body fluids on feed intake and ruminal function: salivation, motility and microbes.

“…Stimulation of Na+ absorption by raising the K+ concentration in the rumen has been demonstrated in other studies (Stacy and Warner, 1%6;Scott, 1967;Warner and Stacy, 1972). However, osmotic pressure per se still was thought to be a significant factor contributing to Na+ absorption from the rumen (Warner and Stacy, 1972). More recently, Gaebel et al (1987) concluded that raising the tonicity of artificial ruminal fluid in sheep to 422 mOsmowter with mannitol did not affect the net absorption rate of Na+, C1-or Mg*.…”

“…This increased absorption occurred provided that water entry into the rumen was minimal. However, when there was substantial movement of water into the rumen (e.g., 70 to 290 mVh, at ruminal osmolalities greater than 400 mOsmoVkg), Na+ absorption appeared to decrease (Warner and Stacy, 1972). The unchanged Na+ absorption observed in the study by Gaebel et al (1987) was associated with a net water flow into the rumen of 65 to 98 mljh.…”

“…Although the concentration of Na+ in the ruminal fluid of cows fed a variety of diets was lower than that of saliva (Bailey, 1961a), Na+ was the principal cation of ruminal fluid from cattle fed various diets with values from 74.5 to 157.8 meq/liter (Ward et al, 1976). Stacy and Warner (1966) calculated that increasing the tonicity of ruminal fluid in sheep led to an increase in the absorption rate of Na+, although the increase was small when tonicity was raised with nonionic sources (mannitol plus urea or glycerol) compared with potassium as KCl or K+ salts of the W A (Warner and Stacy, 1972). Stimulation of Na+ absorption by raising the K+ concentration in the rumen has been demonstrated in other studies (Stacy and Warner, 1%6;Scott, 1967;Warner and Stacy, 1972).…”

“…There was no change in the F' D across the ruminal epithelium in the studies in which the tonicity of artificial ruminal fluid was raised to 422 mOsmoVliter (Gaebel et al, 1987). When KC1 was added to the rumen to elevate the tonicity to 367 mOsmoVkg, the PD increased, but when further KC1 was added to raise tonicity to 526 mOsmol/kg, the PD dropped to a level below that for the resting tonicity (Stacy and Warner, 1972). The decrease in PD at very high tonicities, which was replicated with glycerol, was interpreted as being due to an increase in passive diffusion of water and Na+ from the blood into the rumen.…”

Flow of nitrogen from the rumen and abomasum in cattle and sheep given protein-free nutrients by intragastric infusion

“…When rumen OP were in excess of about 330 mosmol/l there was a net increase in liquid outflow from the rumen, but when the OP was lower there was an associated decrease in liquid outflow. This observation is in agreement with the results of Stacy & Warner (1972), showing that at or aboQt 350 mosmol/l there was a decrease in absorption rate of sodium and movement of water from the blood to the rumen. PEG or CrEDTA as markers.…”

A review of the physiological significance of hypertonic body fluids on feed intake and ruminal function: salivation, motility and microbes.

“…Stimulation of Na+ absorption by raising the K+ concentration in the rumen has been demonstrated in other studies (Stacy and Warner, 1%6;Scott, 1967;Warner and Stacy, 1972). However, osmotic pressure per se still was thought to be a significant factor contributing to Na+ absorption from the rumen (Warner and Stacy, 1972). More recently, Gaebel et al (1987) concluded that raising the tonicity of artificial ruminal fluid in sheep to 422 mOsmowter with mannitol did not affect the net absorption rate of Na+, C1-or Mg*.…”

“…This increased absorption occurred provided that water entry into the rumen was minimal. However, when there was substantial movement of water into the rumen (e.g., 70 to 290 mVh, at ruminal osmolalities greater than 400 mOsmoVkg), Na+ absorption appeared to decrease (Warner and Stacy, 1972). The unchanged Na+ absorption observed in the study by Gaebel et al (1987) was associated with a net water flow into the rumen of 65 to 98 mljh.…”

“…Although the concentration of Na+ in the ruminal fluid of cows fed a variety of diets was lower than that of saliva (Bailey, 1961a), Na+ was the principal cation of ruminal fluid from cattle fed various diets with values from 74.5 to 157.8 meq/liter (Ward et al, 1976). Stacy and Warner (1966) calculated that increasing the tonicity of ruminal fluid in sheep led to an increase in the absorption rate of Na+, although the increase was small when tonicity was raised with nonionic sources (mannitol plus urea or glycerol) compared with potassium as KCl or K+ salts of the W A (Warner and Stacy, 1972). Stimulation of Na+ absorption by raising the K+ concentration in the rumen has been demonstrated in other studies (Stacy and Warner, 1%6;Scott, 1967;Warner and Stacy, 1972).…”

“…There was no change in the F' D across the ruminal epithelium in the studies in which the tonicity of artificial ruminal fluid was raised to 422 mOsmoVliter (Gaebel et al, 1987). When KC1 was added to the rumen to elevate the tonicity to 367 mOsmoVkg, the PD increased, but when further KC1 was added to raise tonicity to 526 mOsmol/kg, the PD dropped to a level below that for the resting tonicity (Stacy and Warner, 1972). The decrease in PD at very high tonicities, which was replicated with glycerol, was interpreted as being due to an increase in passive diffusion of water and Na+ from the blood into the rumen.…”