The Pharmacodynamics of Ascorbic Acid in Cattle. II. in Vivo and in Vitro Loss1,2

Abstract

Summary 1.The ascorbic acid content of rumen juice, intestinal juice, colon and cecal contents, and feces was determined during ascorbic acid absorption studies with steers. 2.Ascorbic acid was recovered from rumen juice for 2 hours following rumen administration of 16g. of ascorbic acid. The vitamin was recovered for 4 and 24 hours, respectively, from colon and cecal contents after placing 4g. of the vitamin directly into these regions. 3.The average ascorbic acid content of feces, cecal, and colon contents was approximately twice as high as jejunal or rumen juice during periods when ascorbic acid was not administered. 4.Placing chlorobutanol in the digestive tract or giving ascorbic acid subcutaneously or intravenously had no apparent effect on the level of ascorbic acid in digestive tract materials. 5.Some fecal elimination of ascorbic acid was evident following administration of ascorbic acid into the digestive tract. 6.In vivo and in vitro studies on rumen and jejunal juice and on colon contents indicated ascorbic acid was quite labile in these media, even though considerable quantities were recovered in vivo several hours after treatment. In vitro samples incubated at 37° C. lost ascorbic acid less rapidly. 7.Some ascorbic acid administered into the rumen, colon, and cecum was eliminated in the feces, with the latter showing the greatest elimination. 8.Autoclaving or preparing bacteria-free filtrates of rumen juice greatly retarded loss of ascorbic acid as compared to untreated rumen juice.