title: Effects of osmolality on water, electrolytes and VFAs absorption from the isolated ruminoreticulum in the cow.
abstract: Effect of the osmolality on the absorption of water, electrolyte and VFAs from the isolated ruminoreticulum under normal feeding condition were investigated in a series of the study to evaluate the rumen as a potential site of absorption in oral fluid therapy of adult cattle. Thirty of 40 l of the test solutions with varying osmotic pressure (100, 200, 300 and 500 mosmol/L, pH 6.8) were prepared using different concentrations of electrolytes and VFAs. These were infused into the isolated and emptied ruminoreticulum, and the absorption rate of water and each components were studied for 3 hrs. Marked absorption of water was observed with solutions more hypotonic than rumen fluid, the extent of which was more extensive with less osmotic pressure; the absorption rate as high as 47.6% was obtained with a solution 100 mosmol in osmotic pressure. When hypertonic solution (500 mosmol/L) was infused, however, water was transported on the contrary from the blood to the rumen. Absorption rates of electrolytes such as Na, K and Cl were increased according to the elevation of osmolalities and their concentrations in the test solutions. VFAs were also absorbed in large quantities (23.9-74.5%) in any test solutions, though the absorption rates were significantly decreased with the elevation of osmolalities. These results may indicate that the ruminal wall has a high absorptive function for water, electrolytes and VFAs when the osmolalities and the concentration of solutes in the ruminal fluid are maintained within a certain range. Furthermore, it is thought that they may work as a rational support for a possible oral fluid therapy even in adult cows.
authors.affiliation: Department of Veterinary Surgery, Faculty of Agriculture, University of Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tabaru
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: E
authors.initials: E
authors.lastname: Kadota
authors.forename: Y
authors.initials: Y
authors.lastname: Murakami
authors.forename: H
authors.initials: H
authors.lastname: Yamada
authors.forename: N
authors.initials: N
authors.lastname: Sasaki
authors.forename: A
authors.initials: A
authors.lastname: Takeuchi
mesh_terms: D000085:Acetates / Q000378:metabolism; D019342:Acetic Acid; D000818:Animals; D002087:Butyrates / Q000378:metabolism; D020148:Butyric Acid; D002417:Cattle / Q000502:physiology*; D002713:Chlorine / Q000378:metabolism; D004573:Electrolytes / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005260:Female; D007408:Intestinal Absorption; D009994:Osmolar Concentration; D011188:Potassium / Q000378:metabolism; D011422:Propionates / Q000378:metabolism; D012159:Reticulum / Q000378:metabolism*; D012417:Rumen / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D013997:Time Factors; D014867:Water / Q000378:metabolism*
chemical_list: D000085:Acetates; D002087:Butyrates; D004573:Electrolytes; D005232:Fatty Acids, Volatile; D011422:Propionates; D014867:Water; D020148:Butyric Acid; D002713:Chlorine; D012964:Sodium; C029658:propionic acid; D019342:Acetic Acid; D011188:Potassium