EFFECT OF UNDERNUTRITION ON THE ABILITY OF THE SHEEP RUMEN TO ABSORB VOLATILE FATTY-ACIDS

The ability of the rumen to absorb the same quantity of VFA with 4 ani mals previously fed with 2 levels of intake was tested. Animals receiv ed maintenance (P1) and half maintenance (P2) energy and nitrogen requ irements successively. Absorption was measured with the empty washed r umen technique. Three litres of a solution buffered at pH 6.30 contain ing VFA (C2:57.1, C3:49.2 and C4:7.4 mM or C2:79.8, C3:23.5 and C4:11. 5 mM) and CoEDTA (7.1 mg Co/l) were introduced in the rumen and regula rly sampled for 3 h. VFA absorption was linear during the trials. Rate s of absorption were expressed as mmol/h or percentage of initial quan tity/h for the comparison between VFA. The order of absorption rate (% /h) was C4 > C3 > C2. Water absorption was not significantly different between the periods whereas VFA absorption rates (mmol/h) were signif icantly reduced after undernutrition. Composition of the solution had no significant effect on VFA absorption rate (%/h).