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Biomedical subjects

F Ahrens

Publications and source records attributed to F Ahrens.

25 records · Page 2Linked to original sources
PubMed1991

The hypocholesterolemic effect of guar gum depends on dietary sucrose--studies in minipigs.

We examined the effect of guar gum on serum lipids if fed together with either 50.3% starch or 50.3% sucrose in a balanced diet to pigs. For this purpose, five adult hypercholesterolemic minipigs (total serum cholesterol 9.0 mmol/l) underwent three consecutive 8-week crossover (control or guar supplementation) feeding experiments (experiment I = cornstarch plus 15 g guar, experiment II = cornstarch plus 30 g guar, experiment III = sucrose plus 30 g guar per day). With the cornstarch-based diet neither 15 g nor 30 g guar gum had an influence on serum total cholesterol or triglyceride levels. Also, the cholesterol concentrations in the lipoprotein fractions did not change significantly during experiments I and II, yet total serum cholesterol concentration was about 20% lower (p less than 0.01) when guar gum was added to the sucrose diet in experiment III. In the presence of sucrose the supplementation of 30 g guar led to a significant decrease (p less than 0.05) of the cholesterol concentrations in the very low-density lipoproteins (VLDL) and high-density lipoproteins (HDL). There was also a tendency for decreased cholesterol levels in the low-density lipoproteins (LDL) after adding 30 g guar to the sucrose diet. Thus, the study demonstrates that guar gum exerts a hypocholesterolemic effect in the presence of sucrose in the diet, but not in the case of starch consumption.

Animals↗
PubMed1991

The effect of source of fiber on ileal and fecal amino acid digestibility and bacterial nitrogen excretion in growing pigs.

Studies were carried out with six barrows (initial BW 50 kg) to determine the effect of two fiber sources on the apparent ileal and fecal N and amino acid digestibilities and bacterial N excretion in feces. The pigs, fitted with a simple T-cannula at the distal ileum, were fed three cornstarch-based diets formulated to contain 16% CP from soybean meal according to a repeated 3 x 3 Latin square design. Diet 1 did not contain additional fiber. Diets 2 and 3 contained 10% powdered cellulose and 10% barley straw (ground through a 2-mm mesh screen), included at the expense of cornstarch, respectively. The pigs were fed 900 g at each meal twice daily, 0800 and 2000. Feces were collected for 48 h after a 10-d adaptation period. Thereafter, ileal digesta were collected for 24 h. Chromic oxide was used as a digestibility marker. With the exception of leucine, the inclusion of fiber did not affect (P greater than .05) the ileal digestibilities of the indispensable amino acids. The values for the average of the ileal digestibilities of the indispensable amino acids were 85.3, 82.9, and 83.2% for diets 1, 2, and 3, respectively. On the other hand, the inclusion of fiber decreased (P less than .05) the fecal digestibilities of all the indispensable amino acids. The values for the average of the fecal digestibilities of the indispensable amino acids were 91.7, 87.4, and 89.1% for diets 1, 2, and 3, respectively. These decreases resulted from an increase (P less than .05) in the excretion of bacterial N, which was measured using 2,6-diaminopimelic acid as a marker. In conclusion, as measured with the ileal analysis method, the inclusion of fiber had little effect on the digestible amino acid supply.

Amino Acids↗
PubMed1988

Effect of starch malabsorption on colonic function and metabolism in humans.

To study the impact of starch on colonic function and metabolism, 12 healthy volunteers consumed a controlled diet rich in starch for two 4-wk periods. In one of the study periods they received the glucosidase inhibitor acarbose (BAY g 5421) and placebo in the other. Stool wet weight increased by 68%, stool dry weight by 57%, fecal water content by 73%, and the mean transit time by 30% on acarbose. Breath hydrogen was significantly higher on acarbose, indicating stimulated carbohydrate fermentation in the colon. Fecal bacterial mass (+78%), total stool nitrogen (+53%), bacterial nitrogen (+200%), and stool fat (+56%) were higher in the acarbose than in the control period. The stimulation of fermentation in the human large intestine may be important in colonic and possibly other diseases.

Acarbose↗
PubMed1988

Influence of casein versus soy protein isolate on lipid metabolism of minipigs.

This report describes whether a complete exchange of soy protein isolate for casein affects serum lipid or lipoprotein levels. For this purpose, 10 adult minipigs underwent two 6-week crossover experiments, one with 11 and one with 22 weight % protein in a western-style diet. Cholesterol levels were 2.02 +/- 0.06 and 1.98 +/- 0.04 mmol/l with casein and soy, respectively (22 weight %) and 2.08 +/- 0.06 and 2.04 +/- 0.05 mmol/l, respectively (11 weight %). There was a significant rise of high-density lipoprotein cholesterol by the lower protein intake, both with casein and soy. In all experiments nitrogen balance was positive. Soy feeding was accompanied by a significant rise of fecal bacterial protein excretion, as calculated from diaminopimelic acid. In summary, no statistically significant difference of plasma or low-density lipoprotein cholesterol levels were observed, neither due to the kind nor to the amount of dietary protein.

Animals↗
PubMed1986

Effects of oral and intracecal pectin administration on blood lipids in minipigs.

The effects on blood lipids of oral and intracecal pectin administration for 4 wk were examined in six male adult hypercholesterolemic minipigs (total serum cholesterol = 8.4 mmol/L. The pigs were fitted with a cecal cannula and were assigned to three groups of two pigs each; the groups underwent an experiment in 3 X 3 Latin square design. The control period was designated as that during which water was infused into the cecum. Total serum cholesterol concentration was about 50% lower after feeding 75 g pectin per day than during the control period. The intracecal infusion of the same amount of pectin had no effect on total serum cholesterol concentration compared to the control period. The cholesterol level in the low density lipoproteins (LDL), in the very low density lipoproteins (VLDL) and in the high density lipoproteins (HDL) was lower after feeding pectin than in the control period. The HDL cholesterol, but not LDL or VLDL cholesterol, was at a lower level after intracecal infusion of pectin than during the control period. Thus, the study clearly demonstrates that the passage of pectin through the small intestine is necessary for its hypocholesterolemic action.

Administration, Oral↗
PubMed1983

Antisecretory effects of berberine with morphine, clonidine, L-phenylephrine, yohimbine or neostigmine in pig jejunum.

The effects of berberine alone or in combination with morphine, clonidine, L-phenylephrine or yohimbine were compared in Escherichia coli heat-stable enterotoxin (ST)-exposed ligated jejunal loops in 2 week old pigs. In addition, net water and electrolyte fluxes in normal jejunal loops were measured in the presence of neostigmine, morphine, clonidine, L-phenylephrine or yohimbine alone or in combination with berberine. Berberine, morphine, clonidine and L-phenylephrine each reduced the net secretion of water and electrolytes induced by ST (P less than 0.05). A significant enhancement of antisecretory effect was observed only with the combination of berberine and L-phenylephrine. Yohimbine or neostigmine augmented the net loss of water and electrolytes produced by ST. Yohimbine did not block the antisecretory action of berberine. In normal jejunum, there was no significant difference in water and ion absorption between adrenergic or opiate agonists alone and their combination with berberine. Neostigmine reversed absorption to net secretion in normal jejunum and this effect was significantly reduced by berberine. The anti-secretory action of berberine appears similar to that of alpha 2-adrenergic agonists, opiates, and anticholinergic agents.

Animals↗