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Biomedical subjects

A G Low

Publications and source records attributed to A G Low.

33 records · Page 2Linked to original sources
PubMed1979

Studies on digestion and absorption in the intestines of growing pigs. 5. Measurements of the flow of nitrogen.

1. Digesta were collected from twenty-three pigs, initially of 30 kg live weight, and fitted with single Ash re-entrant cannulas in either the duodenum, jejunum or ileum. A further twenty-four pigs were used in a conventional digestibility trial. 2. Three approximately isonitrogenous diets were used; they contained: barley, fine wheat ofal, white fish meal, minerals and vitamins (diet BWF), starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut (diet SSG) or casein (diet SSC). 3. The flow-rates of nitrogen (N), liquid-fraction N (LN) and non-protein liquid-fraction N (NPLN) were measured hourly in the duodenum and every 6 h in the ileum during 24 h collection periods. Faeces were collected during 5 d periods. 4. Marked increases in flow of N, LN and NPLN were seen in the duodenum and jejunum after feeding each diet, but not in the ileum. 5. Values for, N output: intake from the duodenal, jejunal or ideal cannulas and in faeces in 24 h periods were respectively: 0.98, 0.88, 0.25 and 0.21 for diet BWF; 1.00, 0.97, 0.22 and 0.24 for diet SSG; 0.98, 0.73, 0.09 and 0.03 for diet SSC. The corresponding values for LN in the duodenum, jejunum and ileum respectively were: 0.53, 0.53 and 0.12 for diet BWF; 0.46, 0.60 AND 0.13 FOR DIet SSG' 0.57, 0.50 and 0.06 for diet SSC. The corresponding values for NPLN in the duodenum, jejunum and ileum respectively were: 0.41, 0.38 and 0.09 for diet BWF; 0.35, 0.36 AND 0.08 FOR DIET SSG; 0.46, 0.38 AND 0.04 for diet SSC. 6. The results are discussed in relation to similar studies, particularly in pigs with duodenal cannulas, in which widely different observations were made.

Animals↗
PubMed1979

Studies on digestion and absorption in the intestines of growing pigs. 6. Measurements of the flow of amino acids.

1. Digesta were collected from seventeen pigs initially of 30 kg live weight fitted with single re-entrant cannulas in either the duodenum, jejunum or ileum. A further twenty-four pigs were used in a conventional digestibility trial. 2. The pigs received three types of diet containing: barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize, oil, cellulose, minerals and vitamins and either groundnut (diet SSG) or casein (diet SSC). 3. Amino acids were measured in samples representative of the digesta flow in 24 h periods and in the faeces collected in 5 d periods. 4. For each diet the total flow in 24 h periods in the duodenum for aspartic acid, threonine, serine and glycine exceeded or equalled intake, while the amounts of the other amino acids were usually rather less than intake. 5. For each diet in the jejunum, the amounts of glycine and cystine exceeded intake in 24 h periods, while methionine, arginine and tyrosine were the most rapidly absorbed amino acids anterior to the cannula site. On average 0.22, 0.25 and 0.31 of the dietary amino acids were absorbed anterior to the cannula site for diets BWF, SSG and SSC, respectively. 6. For each diet in the ileum, the least apparently absorbed dietary amino acids were glycine and cystine. On average 0.81, 0.83 and 0.95 of the dietary amino acids were absorbed anterior to the cannula site for diets BWF, SSG and SSC, respectively. 7. There was net disappearance of most amino acids in the large intestine, but some net accumulation occurred in this region. 8. The results are discussed in relation to the amino acid composition of endogenous secretions (particularly glycine in bile), protease and peptidase specificity, free amino acid absorption and the role of the microflora in the large intestine.

Amino Acids↗
PubMed1978

Studies on digestion and absorption in the intestines of growing pigs. 2. Measurements of the flow of dry matter, ash and water.

1. Digesta were collected from twenty-three pigs, initially of 30 kg live weight, and fitted with single Ash re-entrant cannulas in either the duodenum, jejunum or ileum. A further twenty-four pigs were used in a conventional digestibility trial. 2. The diets contained: barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut (diet SSG) or casein (diet SSC). 3. The flow-rates of dry matter (DM), ash and water were measured hourly in the duodenum and jejunum, and every 6 h in the ileum during 24 h collection periods. Faeces were collected during 5 d periods. 4. Marked increases in the flow rates of each of the digesta components after feeding each diet were observed in the duodenum and jejunum, but not in the ileum. The total flow in 24 h periods was much lower in the ileum than at the other sites. 5. Values for the ratio, DM output: intake for DM outputs from the duodenal, jejunal or ileal cannulas, and in faeces, in 24 h periods were respectively 0.94, 0.81, 0.28 and 0.22 for diet BWF; 0.96, 0.76, 0.20 and 0.15 for diet SSG; 0.96, 0.73, 0.08 and 0.04 for diet SSC. The corresponding values for ash were: 1.47, 1.65, 0.74 and 0.53 for diet BWF; 1.28, 1.34, 0.59 and 0.51 for diet SSG; 1.63, 1.35, 0.50 and 0.26 for diet SSC. The corresponding values for water were: 3.49, 3.41, 0.88 and 0.18 for diet BWF, 2.75, 2.80, 0.80 and 0.08 for diet SSG and 2.61, 1.87, 0.23 and 0.01 for diet SSC.

Animal Feed↗
PubMed1977

Dry matter and nitrogen in the duodenal contents of growing pigs: a discrepancy explained.

1. Discrepancies between the results obtained from experiments on pigs with re-entrant duodenal cannulas have been investigated with reference to diet, cannula site and collection procedure. 2. The results obtained from a sealed automatic collection system were different from those obtained from an open manual method and it was concluded that the maintenance of gut intra-luminal pressure in the automatic system was the causative factor.

Animal Nutritional Physiological Phenomena↗
PubMed1976

Studies on digestion and absorption in the intestines of growing pigs. Measurements of the flow of digesta and pH.

1. Thirty-five pigs were fitted with single re-entrant cannulas in either the duodenum, jejunum or ileum. A further twenty-four pigs were used in a conventional digestibility trial. 2. Methods for collecting, sampling and returning digesta were developed. 3. A 'practical-type' diet and two purfied diets were used, fed twice daily. 4. Flow and pH of digesta were measured hourly in the duodenum and jejunum, and every 6 h in the ileum. 5. In the duodenum and jejunum there were clear flow responses to feeding, while such an effect was not found in the ileum where the flow-rate was much lower and more uniform than in the former sites. 6. In the duodenum and jejunum, and within 6 h periods in the ileum, there was considerable variation in the flow-rate between different pigs within each hour but there was less variation in pH. 7. The pattern of flow in the duodenum and jejunum was similar for each of the diets but the total flow and the average pH in 24 h differed significantly between diets. There were more digesta of a lower pH from the 'practical-type' diet than the purified diets. 8. The pH in the duodenum was highest after feeding and decreased with increasing time after feeding. In the jejunum and ileum the pH-varied over a much smaller range than in the duodenum. 9. Collections for 6 h periods appeared to be insufficiently long to predict the values obtained in 24 h collections with reasonable accuracy.

Animal Feed↗