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Doctoral thesis, 2001

Weaning of pigs with special focus on the intestinal health

Melin, Lennart;

Abstract

Post weaning diarrhoea (PWD) is a disease affecting pigs world wide. PWD is E. coliassociated but the background is clearly multifactorial. In this work, weaning of piglets was studied with focus on selected faecal microfloras and selected immune functions. However, the work also focused on health status and a model to induce PWD was developed. The work is divided in five separate studies:

In the first study, a weaning of healthy piglets was monitored. The phagocyting and killing capacity ofneutrophils in serum was found sufficient from day 6 post partum and these functions were not affected by weaning. Despite absence of diarrhoea, a disturbance ofthe balance in tire coliform flora was observed during the weeks post weaning.

In the second study, the influence of feed supplementation with 2500 ppm ZnO was monitored in healthy pigs. The disturbance of the coliform flora due to weaning was reduced.

ingle pathogenic strain ofE. coli was monitored. One pathogenic strain ofE. coli was not sufficient to induce PWD. However, challenged pigs displayed a longer period with a disturbed coliform flora titan control pigs. The leukocyte levels increased due to weaning regardless of bacterial challenge. Some immune responses were decreased due to weaning, but the pigs were found capable to mount relevant immune responses. The levels ofthese responses were however not validated.

In the fourth study, the influence ofseveral pathogenic strains ofE. coli was monitored. Further, ACTH was given to some groups simulating weaning under stressful conditions. Three pathogenic strains together induced PWD. PWD was also induced by one serotype in connection to shed ofrotavirus. Rotavirus itself did not induce PWD. ACTH was not required to induce PWD, but amplified clinical signs.

In the fifth study, different feed related prophylactic measures to prevent PWD were monitored. ZnO-enrichment of feed, meal feed with lactose and dietary fibres; and a probiotic comprising 60 non-pathogenic E. coli-stiains all appeared to have a potential to prevent PWD.

Keywords

pig; weaning; diarrhoea; Escherichia coli; infection model; faecal microflora; diversity; immunology; probiotics; feed

Published in

Acta Universitatis Agriculturae Sueciae. Veterinaria

2001, number: 112
ISBN: 91-576-5945-1
Publisher: Swedish University of Agricultural Sciences

Authors' information

Melin, Lennart
Swedish University of Agricultural Sciences, Department of Large Animal Clinical Sciences
Melin, Lennart
National Veterinary Institute (SVA)

UKÄ Subject classification

Clinical Science

URI (permanent link to this page)

https://res.slu.se/id/publ/117496