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Biomedical subjects

A G Low

Publications and source records attributed to A G Low.

At least 19 recordsLinked to original sources
PubMed1995

The effect of high-molecular-weight guar gum on net apparent glucose absorption and net apparent insulin and gastric inhibitory polypeptide production in the growing pig: relationship to rheological changes in jejunal digesta.

The present study was designed to determine the quantitative effects of starchy meals containing guar gum on rates of net apparent glucose absorption and net apparent insulin and gastric inhibitory polypeptide (GIP) production in growing pigs. The effects of these meals on the viscosity of jejunal digesta were also examined and correlated to changes in glucose absorption. Four growing pigs were each given either a low-fat semi-purified diet (control) or the same diet supplemented with a high-molecular-weight guar gum at concentrations in the diet of 20 or 40 g/kg. Blood samples were removed simultaneously via indwelling catheters from the mesenteric artery and the hepatic portal vein. Samples of jejunal digesta were removed via a T-piece cannula and used immediately for viscosity measurements at 39 degrees. The 'zero-shear' viscosity of each sample was then calculated. Blood-flow measurements were made using an ultrasonic flow probe fitted to the hepatic portal vein. All measurements were made at intervals of 10 or 30 min during a 4 h postprandial period. Meals containing guar gum significantly increased (P < 0.05) the viscosity of jejunal digesta, an effect that was strongly dependent on the concentration of guar gum in the original diet. No significant differences in blood-flow rates were found between the control and guar-containing diets. Both concentrations of guar gum significantly reduced (P < 0.05) glucose absorption and insulin and GIP secretion rates over the 4 h postprandial period. An inverse relationship between the rate of glucose absorption and the 'zero-shear' viscosity of jejunal digesta was found. This study also provides direct evidence for the important role played by the enteroinsular axis in modifying the glycaemic response to a meal containing guar gum.

Animals↗
PubMed1994

Effect of baked beans (Phaseolus vulgaris) on steroid metabolism and non-starch polysaccharide output of hypercholesterolaemic pigs with or without an ileo-rectal anastomosis.

The plasma-cholesterol-lowering effects of some dietary legumes are now well established from animal and human studies, but the mechanism is not completely understood. The present study investigated the effect of baked beans (Phaseolus vulgaris) on steroid metabolism of hypercholesterolaemic pigs. Three groups of four pigs were studied: baseline (BL), normal pigs (NP) and those previously prepared with an ileo-rectal anastomosis to nullify the function of the large intestine (IR). All three groups were given a semi-purified control diet, with about 40% energy as fat (polyunsaturated:saturated fatty acid (P:S) ratio 0.3), supplemented with 10 g cholesterol/kg, for 14 d. Then IR and NP pigs were fed for 28 d on a diet supplemented with 10 g cholesterol/kg and 300 g baked beans/kg (dry-matter basis), so that the 40% contribution to energy from fat was maintained (P:S ratio 0.3). Group BL was fed on the control diet throughout. The intact pigs (NP) fed on baked beans showed considerable differences compared with the other groups, as follows: (a) reduced plasma cholesterol (NS); (b) higher concentration of cholesterol in bile (NS); (c) higher concentration of bile acids, especially secondary bile acids, in bile (P < 0.05); (d) reduced elimination of bile acids in faeces, especially secondary bile acids (P < 0.05); (e) higher excretion of coprostanol and lower elimination of cholesterol in faeces (P < 0.05). From these findings it is proposed that a baked-bean-enriched diet potentiates bacterial fermentation and steroid degradation in the large intestine and enhances conservation of bile acids and cholesterol within the enterohepatic circulation. The high concentration of bile acids and cholesterol in bile may thus promote feedback inhibition of hepatic cholesterol synthesis, and hence, reduce plasma cholesterol.

Anastomosis, Surgical↗
PubMed1993

Comparative effects of four legume species on plasma lipids and faecal steroid excretion in hypercholesterolaemic pigs.

The effect of four species of legume seeds on plasma cholesterol levels and faecal steroid excretion was studied in pigs. Thirty-six growing boars were randomly allocated in groups of six to six diets which they ate continuously for 42 d. The diets fed were: 1, a semi-purified (SP; control group 1) diet; 2, SP + 10 g cholesterol/kg (control group 2); 3, 4, 5, 6, SP + cooked legumes (70:30, w/w; respectively baked beans (Phaseolus vulgaris), peas (Pisum sativum), lentils (Lens culinaris Medik.), butter beans (Phaseolus lunatus)) + 10 g cholesterol/kg. Fasting blood samples were taken on days 0, 14, 28, and 42 for the determination of total plasma cholesterol, high-density-lipoprotein (HDL)-cholesterol and triacylglycerols. Between days 7 and 11 and days 28 and 32 complete 5 d faecal collections were made for the measurement of neutral, acidic and conjugated steroids. After 42 d total cholesterol and HDL-cholesterol levels were raised significantly in all groups, but to different extents. In comparison with control group 2, diet-induced hypercholesterolaemia was significantly inhibited in the groups consuming baked beans, peas and butter beans, although HDL-cholesterol levels were maintained. Faecal steroid excretion by the legume groups was not significantly different from that of control group 2. The results suggest that the mechanism for the hypocholesterolaemic effect does not involve increased hepatic bile acid synthesis and thereby increased cholesterol clearance via the intestinal route.

Animals↗
PubMed1993

The effect of graded inclusion of baked beans (Phaseolus vulgaris) on plasma and liver lipids in hypercholesterolaemic pigs given a Western-type diet.

The aim of the present study was to measure the effect of graded inclusion of baked beans (Phaseolus vulgaris) on plasma and liver lipids in hypercholesterolaemic pigs fed on a Western-type diet. Twenty-four Large White x Landrace pigs of about 30 kg body weight were made hypercholesterolaemic by feeding a semi-purified diet, high in saturated fat and supplemented with 10 g cholesterol/kg, for 14 d. After that, six pigs were randomly assigned to one of the four experimental groups. They received their respective diets, containing 0, 100, 200 or 300 g baked beans/kg, on a dry-matter basis, for a further 28 d. Fasting blood samples were taken and analysed for total plasma cholesterol, lipoproteins and triacylglycerols. After the pigs were slaughtered at the end of the study, livers were analysed for their cholesterol content. Consumption of baked beans at 100, 200 and 300 g/kg reduced plasma total cholesterol by 5.3, 20.2 and 35.6% respectively. However, only the diet with 300 g baked beans/kg showed a significant reduction (P < 0.05) compared with the control (without baked beans). The level of low-density-lipoprotein-cholesterol was also significantly (P < 0.05) reduced by 48% at 300 g baked beans/kg. Plasma very-low-density-lipoprotein-cholesterol, high-density-lipoprotein-cholesterol and triacylglycerol contents were not affected by bean consumption. The supplements of 200 and 300 g baked beans/kg promoted a significant (P < 0.05) reduction of about 50% in cholesterol deposition in the liver, compared with the control.

Animals↗
PubMed1993

Adaptation to the digestion of non-starch polysaccharide in growing pigs fed on cereal or semi-purified basal diets.

Pigs (25-45 kg) were fed on either cereal or semi-purified basal diets supplemented with either high or low levels of sugar-beet pulp or wood cellulose (Solka-floc). The apparent digestibility and retention of N and apparent digestibility and metabolizability of energy (GE) and the apparent digestibility of non-starch polysaccharides (NSP) and their constituent monomers were measured during weeks 2, 4 and 6 of the trial. N and GE were less well-digested, retained or metabolized from cereal basal diets than from the corresponding semi-purified diets during all three periods. NSP from sugar-beet pulp was highly digestible, unlike that from Solka-floc which was relatively poorly digested. These differences of NSP digestibility were seen more clearly when incorporated in semi-purified diets. There was no significant increase in the digestibility or retention of N, or digestibility or metabolizability of GE, or in the digestibility of sugar-beet pulp NSP with increasing time-period on the diets. In contrast, the digestibility of Solka-floc NSP tended to increase with the time-period. The digestibility of NSP from the semi-purified diet with the high level of Solka-floc inclusion was much lower than that for the low level of inclusion, indicating that microbial activity had been reduced. In conclusion, adaptation to the diets in terms of N and GE balance may be complete after 1 week, but 3-5 weeks may be necessary before stability of measurements of the digestibility of resistant NSP monomers can be obtained.

Adaptation, Physiological↗
PubMed1990

Measurement of transit time of digesta through sections of gastrointestinal tract of pigs fed with diets containing various sources of dietary fibre (non-starch polysaccharides).

The effects of various sources of dietary fibre (defined as non-starch polysaccharides (NSP] on the transit time (TT) of digesta through sections of digestive tract were measured in pigs of 30-85 kg. The pigs were fitted with simple cannulas in the terminal ileum, caecum and mid-colon. Diets in experiments 1-3 were based on barley, wheat, soya bean meal and fish meal with NSP added in the form of wood cellulose (experiment 1), guar gum (experiment 2), wheat bran, pectin (experiment 3). Lactulose was also included in experiment 3 because of its NSP-like effects. Diets in experiments 4 and 5 were based on starch and casein and contained Phaseoluos vulgaris or Pisum sativum (experiment 4) and sugar beet pulp or wheat bran (experiment 5). Transit time (TT) was measured using 103Ruthenium phenanthroline to label solids and 51Chromium complexed to EDTA for liquids. Samples were taken every 3 h after marker administration for 51 h from all cannulas and the faecal output was collected every 3 h. The values obtained were very variable. The range of TT (h) defined as first arrival of markers and peak marker level was 3-12.2 and 3-12.2 to the ileum, 3-22.3 and 4.5-22.3 to the caecum, 4.5-50.3 and 16.5-48.8 to the colon and 24- less than 51 and 30- less than 51 to the rectum respectively.

Animal Feed↗
PubMed1989

The effect of daily baked bean (Phaseolus vulgaris) consumption on the plasma lipid levels of young, normo-cholesterolaemic men.

1. Thirteen normo-cholesterolaemic male students consumed one 450 g can of baked beans (Phaseolus vulgaris) in tomato sauce, daily, for 14 d as part of their normal diet. After a 14 d washout period, eleven of the students went on to consume one 440 g can of spaghetti in tomato sauce, daily, for 14 d. 2. Fasting blood samples were taken frequently for measurement of plasma cholesterol, high-density lipoprotein (HDL)-cholesterol, triacylglycerols, glucose, insulin and C-peptide. Diet diaries (3 d) were completed by the subjects during each period. 3. Consumption of beans and spaghetti led to a significant reduction in the amount of fat eaten daily (P less than 0.05). Bean consumption also resulted in significant increases in protein, fibre and sugar intakes (P less than 0.02, P less than 0.001 and P less than 0.05 respectively). 4. During the bean-eating period the mean total plasma cholesterol level of the students fell significantly from 5.1 to 4.5 mmol/l (P less than 0.02). No reduction in plasma cholesterol occurred during the spaghetti-eating period. 5. HDL-cholesterol levels fell significantly during both periods (P less than 0.001), but HDL:total cholesterol ratio was significantly reduced only during the spaghetti-eating period (P less than 0.001). Neither beans nor spaghetti affected triacylglycerol, insulin or C-peptide levels. 6. The benefits of a legume-rich diet are discussed.

Adolescent↗
PubMed1987

The influence of diets based on whole wheat, wheat flour and wheat bran on exocrine pancreatic secretion in pigs.

Six pigs, initially 40 kg live weight, were prepared with a duodenal pouch for collection of pancreatic juice to assess the influence of the type and amount of dietary fiber on exocrine pancreatic secretion. Four isonitrogenous diets were fed to each pig: W (whole wheat); WBS (whole wheat, wheat bran, wheat starch); WFS (whole wheat, wheat flour, wheat starch); and FC (wheat flour, wood cellulose). Wheat and wheat fractions came from the same batch of wheat. Crude fiber and dietary fiber (nonstarch polysaccharide) contents of diets W, WBS, WFS and FC (g/kg), respectively, were 40.8, 101.8; 63.7, 201.2; 20.5, 50.3; and 39.0, 60.7. Mean volumes of pancreatic juice (mL/24 h) for diets W, WBS, WFS and FC, respectively, were 4108, 4560, 2556 and 1757. Total enzymic and electrolyte concentrations were not significantly affected by diet changes, but mean protein and amylase outputs were lower for diet FC than for the others. It was concluded that the principal effect of increasing the dietary fiber content of the diets was to increase the volume of pancreatic juice and that this may have been due to noncellulosic components of the dietary fiber.

Animals↗
PubMed1986

Effect of guar gum on gastric emptying in growing pigs.

1. Simple gastric cannulas were surgically fitted to four pigs, initially of 30 kg live weight, to examine the effects of guar gum on gastric emptying. 2. Four semi-purified high-fat diets based on starch, casein, soya-bean oil and tallow were given to each pig. They contained 0 (control), 20, 40 or 60 g powdered guar gum/kg diet. The meals as fed contained 257 g dry matter (DM)/kg. 3. The contents of the stomach were evacuated, with rinsing, before feeding or 0.5, 1, 2 or 4 h after feeding. 4. The mean pH of the digesta was unaffected by guar gum until 4 h after feeding when the value increased as the amount of guar gum in the diet rose. 5. The only significant effects of guar gum on the emptying of digesta and its components (compared with the control diet) were to reduce the rate of emptying of (a) digesta 1 h after feeding (60 g/kg diet) and 4 h after feeding (40 and 60 g/kg diets), (b) dry matter and glucose 1 h after feeding (60 g/kg diet), (c) nitrogen 1 h after feeding (60 g/kg diet) and 4 h after feeding (40 and 60 g/kg diets). 6. When expressed on a half-time (T50) basis, the emptying of digesta and N (but not of DM and glucose) were significantly slower for diets containing 40 and 60 g guar gum/kg than for the control diet. 7. The apparent viscosity of the gastric digesta ranged between 0.5 and 23.7% of the values for the diets as consumed. 8. It was concluded that the effects of guar gum on gastric emptying of high-solid meals were small, and that this was unlikely to be an important aspect of the mechanism by which guar gum reduces postprandial blood glucose concentrations.

Animals↗
PubMed1986

Effect of various types of dietary fibre on gastric emptying in growing pigs.

1. Five pigs initially of 40-50 kg live weight were fitted with simple gastric cannulas which permitted complete evacuation and sampling of gastric digesta once daily. 2. The effects of addition of four types of dietary fibre (wheat bran (WB; 40 g/kg), sodium carboxymethylcellulose (CMC; 40 g/kg), high-methoxy citrus pectin (Pe; 40 g/kg) and granulated guar gum (G; 40 g/kg] on gastric emptying of a semi-purified diet during 4 h following a meal were measured. 3. Each of the test diets and the control diet (C) were given to each pig for 1 week using a 5 x 5 Latin-square arrangement. Digesta were collected before and 0.5, 1, 2 or 4 h after feeding on the last 5 d of each week. 4. The mean gastric pH was not significantly affected by diet except 2 h after feeding (CMC higher than C) and 4 h (Pe, G and CMC higher than C). 5. Compared with diet C, the rate of gastric emptying of digesta was significantly slower for diet G, 1, 2 and 4 h after feeding, and 2 and 4 h after feeding for diet CMC. 6. The rates of gastric emptying of digesta components were not significantly reduced by dietary fibre except for dry matter (DM) (diet CMC 2 h and diet B 4 h after feeding), total nitrogen (TN) (diet G 2 h after feeding) and total glucose (diet Pe 2 h after feeding). 7. There were no significant effects of diet on trichloroacetic-acid-soluble N:TN. 8. When gastric emptying was expressed in terms of half-time (T50) values, significant increases (compared with diet C) were found for digesta (diets G and CMC), DM (diet WB) and TN (diet G). 9. The apparent viscosity of the gastric digesta was significantly higher when diets Pe, G, and CMC were given than diets C or WB. Diets Pe and CMC were very viscous in the meal before ingestion, but diet G was not; its high viscosity developed after it had reached the stomach. 10. It is concluded that although those types of dietary fibre which increased meal or gastric viscosity reduced the rate of gastric emptying of digesta, this effect was confined to the liquid phase, because DM, total glucose and TN emptying were largely unaffected. The hypothesis that a reduced rate of gastric emptying may be an important determinant of the decreased rates of glucose absorption observed when such sources of dietary fibre are eaten is not supported by the results presented.

Animals↗
PubMed1985

Gastric emptying of barley-soya-bean diets in the pig: effects of feeding level, supplementary maize oil, sucrose or cellulose, and water intake.

A technique for measuring gastric emptying in growing pigs by complete removal of digesta through a gastric cannula is described. Four pigs were fitted with gastric cannulas and each was used in three trials. The effects of level of feeding (trial 1), cellulose (C), maize-oil (MO) or sucrose (SU) supplementation (trial 2) and the level of water intake (trial 3) on gastric emptying of digesta, dry matter (DM) and nitrogen from a barley-weatings-soya-bean (B) diet were measured during 4 h after the morning feed. In trial 1, pigs were given 0.66, 0.83, 1.00 or 1.17 times their standard level of feeding. As the level of feeding rose, so the weight of digesta, DM and N emptied in the first hour after feeding increased. This trend continued to some extent in the second hour, but no effects of level of feeding were seen in the third and fourth hours. In trial 2, maize-oil addition to the diet significantly reduced the gastric-emptying rate of DM in the second hour after feeding, compared with the rates for diet C. The rate of N emptying was significantly slower for diets MO and SU than for diet C. In trial 3 there were no significant effects of water intake level (1.75, 2.50 and 3.25 times the weight of diet) on the rate of DM or N emptying from the stomach. The rate of digesta (and thus of water) emptying in the first hour after feeding increased significantly as the water intake rose. It was concluded that because the pattern of gastric emptying was very similar despite large differences in nutritional inputs, an important property of the process appeared to be resilience.

Animals↗
PubMed1984

Effect of guar gum on glucose and water absorption from isolated loops of jejunum in conscious growing pigs.

Four pigs initially of 30 kg live weight were surgically prepared with two re-entrant cannulas in the jejunum 1.0 m apart which allowed an isolated loop to be formed through which solutions were perfused. 51Cr-EDTA was used as a marker for measuring net secretion or absorption. A new Ringer solution was made, the ionic content of which resembled more closely that found in the jejunum of pigs given similar diets, than Krebs-Ringer solution. The absorption of glucose and water from Krebs-Ringer and new Ringer solutions was compared. The effect of guar gum on the absorption of glucose and water from solutions of glucose and maltose was studied. There was a trend (not significant) for greater absorption of glucose and water from the new Ringer solution than from the Krebs-Ringer solution. Guar gum significantly reduced the net absorption of glucose from glucose or maltose solutions from 74.2 to 41.4% (P less than 0.001) and 71.1 to 35.0% (P less than 0.001) respectively. Guar gum significantly reduced the net absorption of water from the glucose solution from 42.7 to 8.3% (P less than 0.01) and from the maltose solution from 49.2 to 5.1% (P less than 0.001). The lack of differences between the absorption of glucose from solutions of glucose or maltose suggested that maltase (EC 3.2.1.20) activity was not inhibited to the extent that this limited the rate of glucose absorption.

Animals↗
PubMed1984

Effect of guar gum on nitrogen secretion into isolated loops of jejunum in conscious growing pigs.

Four pigs, initially of 30 kg live weight, were surgically prepared with two re-entrant cannulas in the jejunum, 1.0 m apart. This allowed an isolated loop to be formed through which Ringer solutions were continuously perfused for 6.5-h periods per day. The effects of two Ringer solutions of contrasting composition on nitrogen secretion were measured in a preliminary study. The effects of guar gum (6.7 g/l) on N secretion during perfusions of solutions of glucose or of maltose (20 g/l) were measured. N secretion did not differ significantly between the two Ringer solutions. Addition of guar gum to the solution of glucose increased mean N secretion from 69.2 to 133.9 mg/m per 2 h; the corresponding values for the maltose solution were 75.5 and 120.2 mg/m per 2 h. In both cases the differences were significant (P less than 0.001). Differences between N secretion into glucose and maltose solutions were not significant, either without or with guar gum. Guar gum addition had a greater effect on N secretion in hours 5 and 6 than in hours 1 and 2 of perfusion. It was calculated that guar gum would have increased N section by the mucosa of the whole small intestine from approximately 15 to 27 g/d under the conditions of the study, assuming uniform secretion throughout the organ. These results suggest that certain types of dietary fibre may be important determinants of N secretion by the mucosa of the small intestine. They also suggest that changes in N secretion of this magnitude are of importance in N metabolism because the overall rate of protein synthesis in these pigs was probably about 100 g/d (expressed as N), using values from the literature.

Animals↗
PubMed1983

Studies on gastric digestion of protein and carbohydrate, gastric secretion and exocrine pancreatic secretion in the growing pig.

Six pigs, initially of 35 kg mean live weight, were each fitted with a re-entrant cannula. This was formed on either side of a short pouch of duodenum into which the pancreatic duct opened and which contained a simple cannula linked to the centre of the re-entrant cannula. Each pig received two diets: diet A was based on wheat starch, sucrose and casein, while diet B was based on barley and soya-bean meal. The diets were given in equal amounts at 12 h intervals. Digesta and pancreatic juice were collected continuously during three 12 h periods for each pig on each diet. Mean duodenal output: dietary intake values for diets A and B respectively were: digesta 1.80, 2.86; dry matter 1.05, 1.03; nitrogen 1.05, 1.06; trichloroacetic acid (TCA)-soluble N 7.69, 9.10; glucose 0.97, 0.89. For diet A the proportion of TCA-soluble N in total N rose from 13 to 50% during 12 h, while it was approximately 50% throughout 12 h for diet B. Mean total pepsin (EC 3.4.23.1) activities (units/24 h) were 760449 (diet A) and 1 466 571 (diet B). Salivary and gastric secretions were calculated to be approximately 4 and 8 kg/24 h for diets A and B respectively. Mean flows in pancreatic juice (g/24 h) for diets A and B respectively were: juice 1204, 2182; protein 10.94, 12.10; N 1.98, 2.14; ash 9.46, 17.31; sodium 3.88, 6.91; potassium 0.23, 0.54; calcium 0.031, 0.046; phosphorus 0.024, 0.026. Mean total enzyme activities (units x 10(-3)/24 h) for diets A and B respectively were: trypsin (EC 3.4.21.4) 138, 114; chymotrypsin (EC 3.4.21.1) 84, 84; carboxypeptidase A (EC 3.4.2.1) 5, 4; carboxypeptidase B (EC 3.4.2.2) 15, 17; amylase (EC 3.2.1.1) 1061, 981. It was calculated that the minimum amount of endogenous N from saliva and gastric secretion was 0.3-0.6 g in 24 h. This assumes no absorption of N occurred anterior to the duodenal cannula.

Animals↗
PubMed1982

The influence of diet on the exocrine pancreatic secretion of growing pigs.

1. Pancreatic juice was collected from six pigs of 48 kg initial weight fitted with a collection catheter in the pancreatic duct and a return catheter in the duodenum. 2. Measurements of flow and composition of the juice were made during 24 h periods after adaptation to isonitrogenous diets based on barley, wheatings and fish meal (diet BWF) or starch, sucrose, casein, maize oil and cellulose (diet SSC), given in a change-over design. Measurements were also made during the periods of adaptation to a change from one diet to the other. 3. Mean flow-rates for pigs adapted to diets showed a highly significant four-fold difference between diets; values were 4962 ml/d for diet BWF and 1273 ml/d for diet SSC. The hourly volumes of juice were very variable and showed no clear response to feeding and no consistent diurnal pattern for either diet. 4. There were no significant differences between diets in the specific activities of the proteases. Average values were (units/mg protein) trypsin (EC 3.4.21.4) 29.6, chymotrypsin (EC 3.4.21.1) 7.7, carboxypeptidase A diet BWF than with diet SSC. The specific activities and total outputs of alpha-amylase (EC 3.2.1.1) and lipase (EC 3.1.1.3) were significantly higher for diet BWF than for diet SSC; specific activities for the two diets respectively were: (units/mg protein) alpha-amylase 95-6 and 42.3, lipase 59.0 and 14.5. 5. The higher daily volume of juice with diet BWF was associated with significantly (but only slightly) higher levels of both sodium and potassium, compared with diet SSC. 6. The results are discussed in relation to previous studies on digestion at this Institute, in which pigs with intestinal cannulas were given the same diets.

Animals↗
PubMed1982

The activity of pepsin, chymotrypsin and trypsin during 24 h periods in the small intestine of growing pigs.

1. Digests were collected from twenty-two pigs, of 40 kg mean live weight, and fitted with single re-entrant cannulas in either the duodenum, jejunum or ileum. 2. Three approximately isonitrogenous diets were given to the pigs; their main constituents were: barley, fine wheat offal and white fish meal (diet BWF); starch, sucrose, maize oil, cellulose and either groundnut (diet SSG) or casein (diet SSC). 3. The activities of pepsin, chymotrypsin and trypsin were measured every hour in duodenal digesta during 24 h collection periods. Chymotrypsin and trypsin were also measured every hour in jejunal digests and every 6 h in ileal digesta, during 24 h collection periods. 4. The mean total pepsin activities in the duodenal digesta during 24 h collection periods (units for a 40 kg pig given 1.7 kg diet) were: 7764400 (diet BWF), 6078400 (diet SSG), 5801 600 (diet SSC). 5. The mean total chymotrypsin activities (units for a 40 kg pig given 1.7 kg diet) in digesta in the duodenum, jejunum and ileum respectively were: 62920, 59 560, 21 880 (diet BWF), 78 240, 68 400, 24 680 (diet SSG), 75 280, 76 120, 6160 (diet SSC). 6. The mean total trypsin activities (units for a 40 kg pig given 1.7 kg diet) in digesta from the duodenum, jejunum and ileum, respectively were: 256840, 362840, 77 600 (diet BWF), 211 200, 205 280, 46 720 (diet SSG), 325 720, 428 560, 13 600 (diet SSC). 7. It was calculated that the total weights of pepsin, chymotrypsin and trypsin in duodenal digesta in 24 h periods were between 6.2 and 7.1 g. This represents 20-25% of previously published estimates of the amounts of endogenous protein in this part of the gut.

Animals↗