Piglets of condition 4 were removed from the study, killed by barbiturate overdose, and necropsy was performed. Disease scores were analysed in terms of the mean total disease score obtained per piglet and the mean number of scores greater than 2 recorded per piglet over the challenge period.
Disease scores were subjected to analysis of variance (ANOVA) using Genstat V.
Prior to the inoculation of piglets, cultures were confirmed as bearing K88 pilus by slide agglutination against specific hyperimmune rabbit serum.
Piglets were weighed on the day before weaning, and 3, 7, 10, 15, and 21 days following weaning.
Piglets were considered to be dehydrated if a pinch of skin at the base of the neck did not return to its original shape.
Lethargic piglets were identified as those who were motionless in the pen or required stimuli to move.
Piglets were immediately weaned and fed ad libitum a commercial starter diet for one week after weaning, followed by a grower diet (Barastoc, Australia).
Each treatment group comprised seven replicates per treatment (four or five piglets per replicate).
Given the similarities in the mechanism of pathogenesis of ETEC strains that affect piglets and humans these data suggest that bromelain may be of clinical use to protect against human ETEC infections.
Approval for animal experiments was granted by the Victorian Institute of Animal Science Animal Experimentation Ethics Committee.