Changes in the Intestinal Flora of Young Pigs with Postweaning Diarrhea or Edema Disease

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Abstract
Studies in bacterial flora of normal nursing and weaned pigs showed that Escherichia coli and streptococci were the major aerobes in the gut. Anaerobes were more numerous than aerobes. Populations of all groups of bacteria declined after weaning, aerobes, lactobacilli and bacteroides-clostridia most markedly. After weaning, pigs in a herd affected by postweaning scours experienced increases in intestinal populations of E. coli, lactobacilli, bacteroides-clostridia, oxygen tolerant anaerobes. During scouring dominant strains of E. coli in the gut were hemolytic; streptococci and possibly some oxygen intolerant anaerobes declined in numbers. Proliferation of hemolytic E. coli appears to occur throughout the intestine. Intestinal flora of pigs with edema disease is similar to that of pigs with postweaning scours. A method is described for preparing a defined agar medium for enumeration of anaerobes on the basis of their ability to use specific substrates. Defined medium without an added energy source supported growth of less than 10% of culturable bacteria in swine cecum. With addition of normal carbohydrate substrates numbers of colonies were comparable to those obtained with enriched complex medium. Groups of bacteria were isolated according to their ability to ferment specific substrates. Several genera of bacteria showed a better percentage growth on one substrate than another, which suggests a degree of selectivity by specific substrates. Copyright © 1979. American Society of Animal Science . Copyright 1979 by American Society of Animal Science.