Submitted to: American Society for Experimental Biology and Medicine Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/1996
Publication Date: N/A
Interpretive Summary: Manganese (Mn) is a trace element which is essential for animals, but there is no Recommended Dietary Allowance (RDA) for humans. Part of the reason for this is that very little is known about basic human Mn metabolism, such as how it is absorbed and excreted. In this study, we have developed and tested an experimental surgical procedure which allows us to directly measure Mn absorption and excretion. The experiment used pigs because their digestive tract is very similar to that in humans. We have shown that the surgical procedures can be safety and humanely completed and that the animals recover fully within eight days. An initial experiment with radioactive Mn showed that the procedure can be used to measure Mn absorption and excretion.
Technical Abstract: Determination of true absorption of a nutrient may be complicated if the nutrient undergoes rapid endogenous excretion into the gut following absorption. This allows the unabsorbed nutrient and the nutrient that has been absorbed and re-secreted to mix in the gut, which prevents the identification of the two components by standard techniques. We have developed a method of measuring these two components. Swine were surgically implanted with cannulas in the ileal, portal and jugular veins, the bile duct and the duodenum. Nutrient absorption was quantitated by detecting radioactive tracer in the portal blood. Biliary secretions were collected quantitatively and bile was replaced by reinfusing pre-collected bile through the duodenal cannula. Animals recovered from surgery without outward signs of infection, and other measures indicated that they had completely recovered from the effects of surgery after 6 days. Animals and cannulas were successfully maintained up to 21 days following surgery. Initial studies indicated that the method could be successfully employed to determine manganese absorption and excretion.