The Pharmacodynamics of Ascorbic Acid in Cattle. II. in Vivo and in Vitro Loss

Investigations by Whitnah and Riddell (13), Knight et al. (6), and Vavich et al. (11) have shown that ascorbic acid rapidly is lost in the rumen contents of cattle both in vivo and in vitro.Kendall and Chinn (4) were unable to show in vitro decomposition of ascorbic acid in filtered rumen juice obtained from freshly slaughtered cows.Knight et al. (6) found that • ascorbic acid rapidly disappeared from the rumen contents of a cow (in vivo) after she was fed as much as 150 g. of crystalline ascorbic acid.Studies of rumen juice incubated at 39-42 ° C. revealed that loss of added ascorbic acid was rapid but not as rapid as in vivo.This was attributed to lack of continuous mixing in vitro compared to continuous mixing in vivo.Vavich et al. (11) found that ascorbic acid was destroyed quite slowly in sterilized rumen contents.When dehydrated cereal grasses were fed as a source of ascorbic acid, the vitamin could be demonstrated in the rumen more than 8 hours after feeding, but the highest concentration occurred 2 to 4 hours after feeding.Orally administered crystalline ascorbic acid could be recovered for approximately 2 hours.These authors also removed all rumen contents, flushed the rumen with warm water, and again emptied it.The cow then was fed a low ascorbic acid ration.In vivo and in vitro studies of this material showed little loss of ascorbic acid, but when 2 gallons of the fermenting rumen contents were returned to the rumen, definite loss of added ascorbic acid occurred.Young and James ( 14) and Young and Rettger (15) have reported that human fecal cultures and isolated cultures of Escherichia coli and Aerobacter aerogenes decomposed ascorbic acid under both aerobic and anaerobic conditions.Organisms of the Alcaligenes and Proteus groups did not attack ascorbi~ acid and protected it from atmospheric oxidations but not from bacteria decomposing ascorbic acid.Glucose and lactose "spared" ascorbic acid from oxidation by fecal bacteria.Ascorbic acid-decomposing bacteria which produced gas from ordinary carbohydrates also produced gas when attacking ascorbic acid.Stepp and Schroder (10) also have reported on a strain of Escherichia coli that decomposed ascorbic acid.