The synthesis and absorption of pantothenic acid in the gastrointestinal tract of the adult sheep

A microbiological assay using Lactobacillus plantarum was used to determine the levels of pantothenic acid (PA) in food and digesta samples from sheep fitted with duodenal and ileal re‐entrant cannulas, given a variety of diets. ACP‐bound PA was not measured. With most of the diets studied there was an increase in ‘total’ PA and CoA‐bound PA before the small intestine. Both the increase in CoA‐bound PA prior to the duodenum and the ‘total’ PA reaching the duodenum were positively and significantly related to the microbial dry matter synthesised in the rumen. Free PA at the duodenum was significantly related to the dietary intake of free PA. The apparrent absorption of total PA within the small intestine was significantly related to the quantity entering the small intestine suggesting a passive absorption mechanism. It is suggested that CoA‐bound PA entering the small intestine is hydrolysed to release free PA which is then available for absorption.