IMPACT OF YERSINIA-ENTEROCOLITICA ENTERITIS ON DISACCHARIDASE ACTIVITY AND SMALL-INTESTINAL MORPHOLOGY IN COLOSTRUM-DEPRIVED NEWBORN PIGLETS

The effect of enteritis on the development of the small intestine was examined in newborn, colostrum-deprived piglets infected with a human isolate of Y. enterocolitica (serotype 0:3, biotype 4) soon after birt h. The piglets were killed 3 days (n = 6) or 5 days (n = 8) after infe ction, or antibiotic therapy was commenced on day 5 and the animals ki lled on day 14(n = 5). Compared with the non-infected controls, infect ed animals had reduced mucosal lactase and sucrase, but not maltase ac tivity, while after antibiotic therapy, previously infected piglets ha d a lower lactase and a higher maltase and sucrase activity. Lactase a ctivity was significantly reduced in the duodenum and jejunum, and mea n values were lower in the ileum, but the difference did not reach sig nificance; maltase activity was greater at all ages from the distal je junum to the mid-ileum; sucrase activity was reduced in all segments u p to day 5 but after antibiotic therapy was increased in the jejunum a nd appeared early in the ileum. Enzyme profiles were more mature along the crypt-villus axis in some segments of the intestine in previously infected piglets. Sodium-potassium-ATPase activity was unchanged. The re was a reduced villus height:crypt depth ratio, crypt hyperplasia an d increased crypt cell proliferation. Morphological maturation, indica ted by loss of vacuoles and location of the nucleus at the base of the enterocyte, proceeded distally from the duodenum to ileum from 3 to 1 4 days of age when only the ileum remained immature. In infected pigle ts, there was reduced vacuolation and earlier location of the nucleus at the base of the cell in the distal intestine. Accelerated maturity of specific disaccharidases and enterocyte morphology in infected pigl ets appears to be due to physical damage to the mucosa resulting in fa ster proliferation of crypt cells and migration of enterocytes. It is suggested that this may reduce macromolecular internalisation and impa ir the ability to growth and immunological responses of the gut. utili se dietary carbohydrate and may have long-term effects on