The importance of dietary antigen in the cause of postweaning diarrhea in pigs.

Food was given to pigs before weaning to determine whether a hypersensitive response to dietary antigen might be a predisposing factor to postweaning diarrhea. Small amounts of food increased the severity and accelerated the onset of postweaning diarrhea. Postweaning diarrhea was dependent on the presence within the diet of antigenic material (bovine casein). A weaning diet, containing little antigenic material (hydrolyzed casein), had less effect on sucrase concentration in intestinal brush borders than did diets rich in antigens (native casein). Seemingly, immune-mediated intestinal damage may predispose the pig to postweaning diarrhea.