We intend to asses zinc and copper metabolism at three time points: first, when the infant has an ostomy and is receiving primarily intravenous nutrition, called total parenteral nutrition (TPN), with minimal or no enteral feeds (ie, feeds into the gastrointestinal tract); second, when the infant has an ostomy and is receiving primarily enteral nutrition without TPN; and third, when/if the infant has a surgery to reconnect the bowel and remove the ostomy. Using stable isotope techniques for the second and third parts, we will measure intake compared to excretions (stool in ostomy and urine). A stable isotope is naturally occurring form of a mineral that we can measure, or trace, in the body. It is not radioactive and there are no known risks from it.