Plasma level of antisecretory factor (ASF) and its relation to post-weaning diarrhoea in piglets

Antisecretory factor (ASF) is a regulatory peptide which counteracts diarrhoea in the pig; ASF is rapidly absorbed from the pig intestine, and significantly reduces the incidence of neonatal diarrhoea in the suckling offspring. ASF is synthesized in the central nervous system, and released to the blood stream via the pituitary gland. In two different experiments (n = 8 and n = 4), the blood concentration of ASF was followed in 5-weeks old piglets from day 7 before weaning up to day 12 days after weaning. In both experiments ASF concentrations were significantly (p < 0.01) lower on day three post-weaning, than either before weaning or on days 7 and 12 post-weaning. In another experiment, where plasma ASF activity was determined in relation to clinical signs of diarrhoea seven days post-weaning, it was found to be 0.87 +/- 0.08 units/ml (mean +/- SEM) in healthy weaners (n = 15), but only 0.22 +/- 0.05 units/ml in piglets suffering from diarrhoea (n = 15), the difference being significant. The faecal flora both of healthy weaners and of their matched controls suffering from diarrhoea were subjected to bacteriological examination before and after weaning, and found to be similar in both groups, namely a mixture of aerobic and anaerobic Gram negative rods, Campylobacter jejuni, Staphylococcus aureus/epidermidis, and Enterococcus faecalis. No particular pathogen was predominant in any of the diseased animals.