Intestinal absorption of immunologically intact macromolecules in germfree colostrum-deprived piglets maintained on total parenteral nutrition.

We have compared the neonatal absorption of anti-bovine gamma-globulin (BGG) antibody supplied in colostrum or saline in three groups of piglets born and maintained under different environmental conditions to determine the effect of these conditions on the cessation of intestinal absorption of macromolecules (anti-BGG antibody), termed "closure." An enzyme-linked immunosorbent assay was used to estimate the concentration of anti-BGG antibody in sera from each group of piglets. Three stages of macromolecular absorption through the piglet's intestine could be detected. The first stage is a nonselective massive absorption of macromolecules (in milligram levels) that lasts up to 3 days in germfree (GF) colostrum-deprived or conventional colostrum-fed piglets but up to 5 days in GF piglets maintained on total parenteral nutrition. In this stage, absorption was significantly (r = .05) higher in piglets fed anti-BGG serum with colostrum than in piglets fed anti-BGG serum without colostrum on GF day 0 (31.28% vs 15.59%) and GF-total parenteral nutrition day 3 (3.08% vs 0.11%). Thus, whenever there was the ability to absorb a massive amount of macromolecules, the sow colostrum had an enhancing affect. Although there was a minor effect of environmental or orally received stimuli in delaying closure, absorption of macromolecules decreased in all piglets maintained either parenterally or enterally after day 3. Thus, intestinal closure to massive absorption of macromolecules in piglets is primarily time (age)-dependent. The second stage is a selective absorption of immunoglobulins in much smaller quantities (microgram levels), inasmuch as absorption of 0.02% to 0.1% was determined in all 5-day-old piglets.(ABSTRACT TRUNCATED AT 250 WORDS)