EFFECT OF WEANING IN THE PIG ON ILEAL ION-TRANSPORT MEASURED IN-VITRO

Early weaning in pigs results in small intestinal malabsorption and an increased susceptibility to E. coli infections. This is closely assoc iated with villus shortening and crypt hyperplasia of the small intest ine. The present study compared piglets either weaned at 3 weeks of ag e onto a high soya diet (n = 12) or an egg-based diet (n = 12) with pi glets that remained on the sow (n = 12). Prior to weaning, care was ta ken to ensure that piglets only had access to sows milk. Serum antisoy a IgG was measured 7 days after weaning and sections of the mid-ileum excised and fixed for determination of crypt depth and villus height. Four pieces of 'stripped' mucosa mere mounted in Ussing chambers in Kr ebs-phosphate Ringer (with indomethacin) for determination of short ci rcuit current (SCC) and unidirectional fluxes of Na-22 and Cl-36, half in mucosa-serosa (MS), and hall in serosa-mucosa (SCC) direction. Aft er basal measurements of absorptive capacity of Na, supramaximal doses of prostaglandin E2 (PGE2) and theophylline were added to measure the intestinal secretory capacity for Cl. Anti-soya IgG was elevated in t he group weaned onto soya when compared either with the group weaned o nto egg or the unweaned group. Ail intestinal transport and histologic al parameters were similar in both the weaned groups, although some we re different from the unweaned. The SCC (equal to Na absorption) and t he villus height were reduced two-thirds by weaning, whereas crypt dep th and Cl secretion were similar in all groups. It is suggested that w eaning per se is causal for the observed changes in intestinal transpo rt and morphology, but they are not influenced by whether the weaning diet is soya or egg based.