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Biomedical subjects

D J Hampson

Publications and source records attributed to D J Hampson.

133 records · Page 8Linked to original sources
PubMed1986

Influence of creep feeding and dietary intake after weaning on malabsorption and occurrence of diarrhoea in the newly weaned pig.

The influence the pattern of creep feeding has on the ability of pigs to absorb xylose after weaning at three weeks old was investigated. All weaned pigs showed a reduction in their ability to absorb xylose one week after weaning, but this was not influenced by the pattern of creep feeding before weaning. Diarrhoea occurred in some animals after weaning, but did not occur in pigs which did not have access to creep food before weaning. This protective effect of withholding creep food was associated with a low dietary intake after weaning with this regimen. Pigs which developed diarrhoea tended to be those which consumed more meal after weaning than their contemporaries. Haemolytic enterotoxigenic Escherichia coli and rotaviruses were present in the faeces of most pigs after weaning, but, in those animals that ate too much and developed diarrhoea, excretion of the E coli continued for approximately twice as long as in animals that remained healthy.

Animals↗
PubMed1985

Coliform numbers in the stomach and small intestine of healthy pigs following weaning at three weeks of age.

In 60 weaned and 52 unweaned pigs, aged between 21 and 32 days, the number of coliform organisms in the gastric contents was found to be related to their pH value. The contents were generally more acidic in the weaned animals and contained fewer coliforms. Haemolytic coliform organisms were never identified among selected isolates examined from the gastric contents although in weaned animals the haemolytic enterotoxigenic Escherichia coli serotype 0149: K91, K88a,c (Abbotstown strain) was commonly recovered from the intestines. After weaning, this strain appeared to colonize the anterior small intestine from lower down the tract, and its presence was associated with an increase in the total coliform count at the site from which it was isolated. Rotaviruses were also more commonly detected in the intestinal contents of weaned than unweaned pigs, but their appearance after weaning appeared to be preceded by the proliferation of haemolytic E. coli. The presence of either or both of these potentially enteropathogenic organisms never induced diarrhoea, and although faecal water content increased significantly after weaning, this occurred independently of the presence of both agents.

Animals↗
PubMed1985

The effects of oxytetracycline on the intestinal Escherichia coli flora of newly weaned pigs.

Four recently weaned pigs were dosed orally with oxytetracycline. This caused a rapid increase in the incidence of tetracycline resistance (TcR) among Escherichia coli isolates from the faecal flora. The isolates were differentiated further on the basis of O-serogroup, biotype and resistance pattern. There was no evidence that the administration of the antibiotic selected for a few TcR clones, but rather a relatively large number of TcR strains were identified during the dosing period. Using selective isolation media a proportion of these strains were demonstrated in the minority faecal Esch. coli flora before dosing, while the remainder were recognized for the first time after dosing commenced. The incidence of TcR among Esch. coli isolates also increased after weaning in other pigs which were not dosed with oxytetracycline or any other antibacterial agent. In a proportion of these animals this increase was associated with the dominance of a TcR enteropathogenic serotype (0149:K 91, K 88a, c) in the faecal Esch. coli flora which was probably ingested in small numbers before weaning. The source of other TcR strains was probably the environment in which each pig was placed after weaning.

Animals↗
PubMed1985

A comparison of the ecology of Escherichia coli in the intestine of healthy unweaned pigs and pigs after weaning.

A total of 51 clinically healthy pigs (14 unweaned and 37 weaned) from five litters, and aged 21 to 35 d, were studied. Escherichia coli isolates from the duodenum, jejunum, ileum, caecum and colon were differentiated on the basis of O-serogroup, biotype and resistance pattern. The complexity of the flora was influenced considerably by the presence or absence of the enterotoxigenic serotype 0149: K91, K88a,c (Abbotstown strain). When it was absent the E. coli flora of both weaned and unweaned pigs was complex with up to 25 strains being identified. The majority of these E. coli strains identified in each pig were isolated from only one of the five intestinal sites sampled. On the other hand, when the enterotoxigenic strain was present (14 pigs) it tended to dominate the E. coli flora at all levels of the intestine and this dominance was reflected in a corresponding fall in the total number of E. coli strains isolated per pig.

Animals↗
PubMed1984

The importance of dietary antigen in the cause of postweaning diarrhea in pigs.

Food was given to pigs before weaning to determine whether a hypersensitive response to dietary antigen might be a predisposing factor to postweaning diarrhea. Small amounts of food increased the severity and accelerated the onset of postweaning diarrhea. Postweaning diarrhea was dependent on the presence within the diet of antigenic material (bovine casein). A weaning diet, containing little antigenic material (hydrolyzed casein), had less effect on sucrase concentration in intestinal brush borders than did diets rich in antigens (native casein). Seemingly, immune-mediated intestinal damage may predispose the pig to postweaning diarrhea.

Animal Feed↗