Bromelain protects piglets from diarrhoea caused by oral challenge with K88 positive enterotoxigenic Escherichia coli.
BACKGROUND
K88 positive enterotoxigenic Escherichia coli (K88+ ETEC) is an important cause of diarrhoea in young piglets. K88+ ETEC pathogenesis relies on attachment to specific glycoprotein receptors located on the intestinal mucosa. Proteolytic treatment of these receptors in vitro and in vivo prevents attachment of K88+ ETEC to piglet small intestines and may be of clinical use to prevent K88+ ETEC pathogenesis.


OBJECTIVE
To determine whether bromelain, a proteolytic extract obtained from pineapple stems, would protect piglets against K88+ ETEC diarrhoea and to confirm and extend earlier findings on the effects of bromelain on K88+ ETEC receptors in vivo.


METHODS
Bromelain (0, 12.5, or 125 mg) was orally administered to just weaned piglets for 10 days. One day following commencement of bromelain treatment, piglets were challenged with K88+ ETEC (5 x 10(10) K88ac:0149) for seven days. Intestinal contents from unchallenged piglets were obtained via an intestinal fistula, and tested for their ability to bind K88+ ETEC before and after bromelain treatment.


RESULTS
Both doses of bromelain were successful in reducing the incidence of K88+ ETEC diarrhoea and protected piglets from life threatening disease. Bromelain treated pigs also had significantly increased weight gain compared with untreated pigs. Bromelain only temporarily inhibited K88+ ETEC receptor activity, with receptor activity being regenerated 30 hours following treatment, consistent with the regeneration of new enterocytes.


CONCLUSIONS
Results show that bromelain can temporarily inactivate ETEC receptors in vivo and protect against ETEC induced diarrhoea. Bromelain may therefore be an effective prophylaxis against ETEC infection.
Chandler
D S
DS
Victorian Institute of Animal Science, Attwood, Australia.
Mynott
T L
TL
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D001963:Bromelains / Q000627:therapeutic use*; D003967:Diarrhea / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D010641:Phenotype; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology / Q000517:prevention & control*; D015430:Weight Gain
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001963:Bromelains