Weaning anorexia may contribute to local inflammation in the piglet small intestine

Compromising alterations in villus-crypt structure are common in pigs postweaning. Possible contributions of local inflammatory reactions to villus-crypt alterations during the weaning transition have not been described. This study evaluated local inflammatory responses and their relationship with morphological changes in the intestine in 21-d-old pigs (n = 112) killed either at weaning (Day 0) or 0.5, 1, 2, 4 or 7 d after weaning to either milk- or soy-based pelleted diets. Cumulative intake averaged <100 g during the first 2 d postweaning, regardless of diet. During this period of weaning anorexia, inflammatory T-cell numbers and local expression of the matrix metalloproteinase stromelysin increased while jejunal villus height, crypt depth and major histocompatibility complex (MHC) class l RNA expression decreased. Upon resumption of feed intake by the fourth d postweaning, villus height and crypt depth, CD8⁺ T cell numbers, MHC class I RNA expression and local expression of stromelysin returned to Day 0 values. Together the results indicate that inadequate feed intake during the immediate postweaning period may contribute to intestinal inflammation and thereby compromise villus-crypt structure and function.