THE EFFECTS OF RUMINAL ACIDOSIS ON VOLATILE FATTY-ACID ABSORPTION ANDPLASMA ACTIVITIES OF PANCREATIC-ENZYMES IN LAMBS

Twenty crossbred wethers (41.9 +/- 4.0 kg BW), each fitted with a rumi nal cannula and a jugular catheter, were used in a completely randomiz ed design to examine the effects of ruminal acidosis on plasma activit ies of pancreatic enzymes and fractional rates of VFA absorption. Lamb s had ad libitum access to a 50% concentrate diet. Acidosis was induce d by an intraruminal dose of glucose at 0, 6, 12, or 18 g/kg BW via th e ruminal cannula. Ruminal fluid and plasma were collected 0, 4, 8, 12 , 18, 24, 36, 48, and 72 h after dosing. Ruminal fluid pH was reduced (linear, P < .001) with increasing ruminal glucose. Total ruminal VFA concentration decreased (linear, P < .01) and D(-)-lactate (linear, P < .01) and L(+)-lactate (linear, P = .07) concentrations increased wit h increasing ruminal glucose. Activities of amylase and lipase in plas ma were not affected by luminal glucose (P > .19). Ten days after the acidosis insult, rumens were evacuated and contents were replaced with an isotonic Cr:VFA solution to measure ruminal VFA absorption. Rumina l fluid was collected hourly from 0 to 6 h. Fractional rate of acetate absorption was 13% lower for lambs receiving 18 g/kg BW glucose than for control lambs. In addition, fractional Liquid passage rate was low er (P < .05) in lambs receiving 18 g/kg BW glucose 6 mo after the insu lt of acidosis. These data suggest that a short-term, severe insult of acute acidosis does not result in pancreatic tissue damage but may re sult in reduced ruminal VFA absorption for an extended period of time.