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School of Nutritional Sciences1, Department of Animal Sciences2, The Faculty of Agriculture Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
Summary
Weanling male rats fed a vitamin A deficient (VAD) diet were compared with rats fed the same diet supplemented with vitamin A. Half of the VAD group was repleted with vitamin A at the age of 70 days. There was a decline in weight in the VAD group after 45 days. Serum and liver retinol concentrations were negligible in the VAD groups at 70 days of age. These levels returned to normal in the repleted group within 20 days of supplementation. Histological observations in the intestinal tissues of the experimental animals exhibited reduced villus height (p < 0.05) compared with the vitamin A supplemented group (VAS), reduced number of mucous secreting goblet cells and total enterocytes. In addition, a significantly higher number of proliferating cells was found along the crypt. Disaccharidases (sucrase and maltase), peptidases (gGT) and alkaline phosphatase activities were markedly lower along the brush border (p < 0.05) in the VAD group compared to the VAS group. We also determined the total DNA, RNA and protein in the jejunal tissues per 0.1 mg/tissue in both groups. The RNA production per cell in the VAD groups was notably lower than that of the controls (p < 0.05). Our observation indicates that brush border enzyme levels are altered in animals with vitamin A deficiency, and that phenomenon is augmented when calculated per single cell. This change may be attributed to direct effects of vitamin A on the rate of proliferation and differentiation of the epithelial tissue along the jejunum rather than to gross structural changes along the small intestine.
Keywords
Vitamin A, Brush border enzymes, Rat
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 5, © Verlag Hans Huber AG, Bern
1 Department of Nutrition, Junior College
of Agriculture, Tokyo University of Agriculture, Sakuragaoka 1-1-1
Setagaya-Ku, Tokyo 156, Japan
2 Department of Nutrition, Faculty of Agriculture, Tokyo
University of Agriculture, Sakuragoaka 1-1-1 Setagaya-Ku, Tokyo 156,
Japan
3 Department of Agricultural Chemistry, Faculty of
Agriculture, Tokyo University of Agriculture, Sakuragaoka 1-1-1
Setagaya-Ku, Toky 156, Japan
Summary
The effect of dietary protein levels on tissue-specific distribution and metabolism of vitamin A was studied in rats given [15-14C] retinol (14C-ROH). The weanling rats were fed a low level vitamin A diet for 10 days, then rats (15 rats per group) were divided into 2 groups; one was given a 40% casein diet as a high protein diet (HP-diet), and the other a 5% casein diet as a low protein diet (LP-diet). After 10 days feeding on these diets, 14C-ROH (5 m Ci/rat) was given to both groups, HP-diet and LP-diet, by intraperitoneal injection. The radioactivity in the exhalated gases, urine and feces was measured to estimate the rate of vitamin A metabolism. The tissue specific-distribution of ROH was studied in terms of the radioactivities of the ROH fractions separated by HPLC. The hepatic 14C-ROH content in the HP-diet group was lower than that in the LP-diet group at 24, 48, and 72 hours after administration of 14C-ROH. In contrast, 14C-ROH content in serum, spleen, pancreas, and small intestinal mucosa in the HP-diet group was higher than that in the LP-diet group. The radioactivity of the exhalated gas and feces was higher in the HP-diet group. These results suggest that metabolism of vitamin A is higher with intake of a HP-diet. Thus, dietary protein levels may affect tissue-specific distribution and metabolism of vitamin A, thereby modulating the actions of this vitamin.
Keywords
Vitamin A metabolism, 14C-retinol, Dietary protein levels, Excretion, Exhalated gas
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 5, © Verlag Hans Huber AG, Bern
1 Laboratoire de Biologie et
Biochimie des Lipides EA 2033, Institut de Biologie,
Faculté de Médecine de Montpellier (UM I), Boulevard
Henri IV, 34060 Montpellier, France
2 Service de Gynécologie-Obstetrique,
Hôpital Arnaud de Villeneuve, Centre Hospitalo-Universitaire de
Montpellier, 371 avenue Doyen Giraud, 34295 Montpellier, France
Summary
Little is known about lipid-soluble vitamin placental transfer. We supplemented ten pregnant women ranging in age from 26 to 38 years with vitamin E at a daily dose of 1 g dl-a-tocopherol acetate for 3 days before delivery. All pregnancies ranged from 37 to 39 weeks of gestation at the time of the study. Maternal blood was first drawn during the week preceding supplementation and then just before the delivery by hysterotomy. Neonatal blood was from cord at birth. Supplementation dramatically increased the plasma and red blood cell vitamin E of the mothers. This was true whatever the expression of the vitamin E content, i.e., plasma lipid-normalized or non-normalized vitamin E, and red blood cell vitamin E related to volume of packed cells or to membrane-phospholipid phosphorus. In contrast, the plasma vitamin E content was very low in neonates (3.51 ± 0.38 mg/L) and did not significantly differ from that reported in a previous paper, where plasma was drawn from fetal cord blood of pregnant non-supplemented women belonging to the same geographical population (Cachia et al., Am. J. Obstet. Gynecol. 1995; 173: 4251). This strongly suggests that the transfer of vitamin E through the placental barrier is very low. That the plasma lipid-normalized levels of mothers before supplementation and of neonates did not significantly differ also suggests that the paucity of lipids in the circulating blood of neonates is the cause of the restricted amount of plasma vitamin E. Therefore, the low level of vitamin E in neonates may result from both low maternal placental transfer and neonatal lipid transport peculiarities.
Keywords
Vitamin E, Neonates, Maternal supplementation, Plasma, Red blood cells, Lipid classes, Fatty acids, Placental transfer
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 5, © Verlag Hans Huber AG, Bern
Metabolic Unit, University Children's Hospital, 4005 Basel, Switzerland
Summary
A microbiological, an avidin-binding and a streptavidin-binding method for biotin determination were compared. All three methods detected biotin equally well but they exhibit different specificities for derivatives of biotin. The microbiological assay has the highest specificity and is the method of choice for biotin determination in biotinidase-deficient patients. The specificity of streptavidin-binding has not been investigated so far. Application of the three methods to urine samples of patients with and without biotin therapy indicated that only 50% of biotin equivalents measured with the avidin method correspond to authentic biotin as previously shown. The other 50% comprise mainly bisnorbiotin and biotin-d-sulfoxide. HPLC-separation of urine samples prior to assay confirmed this finding and revealed a bisnorbiotin oxidation product and an unknown compound as further biotin metabolites. The latter was measurable by all three methods and not detectable in plasma ultrafiltrate. This was the only metabolite which was able to restore deficient 3-methylcrotonyl-CoA carboxylase activity in biotin-deficient fibroblasts. The combination of the three methods together with HPLC-separation proved to be a valuable analytical tool for the identification of the main biotin metabolites in biological fluids.
Keywords
Biotin, Biotin metabolites, Avidin-binding, Streptavidin-binding, Lactobacillus plantarum, Specificity, Biotin therapy
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 4, © Verlag Hans Huber AG, Bern
1 Laboratoire de Chimie Analytique,
Institut National Agronomique, 16, rue Claude Bernard, 75005 Paris
(France)
2 Service d'Ophtalmologie, Hôpital Cochin, Paris
(France)
Summary
Cataract formation is believed to result from an oxidative insult
which decreases the antioxidant defense of the lens, particularly the
vitamin C concentration. Upon oxidation, vitamin C contributes with
glucose to protein glycation. It also favours tryptophan oxidation,
resulting in fluorescent peptide cross-links and protein
insolubilisation.
The relationship between cataract and lenticular vitamin C was
analysed in 48 cataractous lens nuclei classified into four severity
grades, considering the sum of the colour and opacity. Ascorbic and
dehydroascorbic acids were quantified by HPLC-fluorescence. The
Amadori product was measured by means of furosine, advanced glycation
end products by their fluorescence and tryptophan concentration by
HPLC-UV.
The lens vitamin C concentration significantly decreased with
cataract severity, but mostly in severe brown cataracts (around 88
mmol/100 g lens in mild cataracts, and 50 mmol/100 g in dark brown
lenses). The dehydroascorbic acid concentration was always low and
stable (1.9 ± 0.9 mmol//100 g), as was the furosine
concentration (0.4 ± 0.1 mmol/g). The fluorescence of insoluble
advanced glycated end products was significantly higher in severe
cataracts than in milder ones. The peptide tryptophan content was
stable but the tryptophan to tyrosine ratio decreased and was highly
correlated to the ascorbic acid concentration. Vitamin C content
appears to be a good indicator of cataract severity, suggesting that
oxidation could take part in cataract progression.
Keywords
Lens, Human cataract, Vitamin C, Dehydroascorbic acid, Furosine, Tryptophan
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 5, © Verlag Hans Huber AG, Bern
Departments of Animal and Poultry Science University of Saskatchewan, Saskatoon, SK, Canada S7N 5B5
Summary
Riboflavin status indices in tissues (brain, liver, heart) and
blood plasma, and performance parameters were studied in male and
female broiler chickens in response to a wide range of dietary
supplementation of riboflavin in order to establish the requirement
for riboflavin in fast growing modern broilers. The birds fed
riboflavin supplemented diets were increasing their body weight at a
higher rate than those fed the unsupplemented diet, but this was
apparent only during the first stage of growth (days 1 to 21).
Supplementation of 2 mg riboflavin per kg was sufficient to support
the maximum growth rate. Feed consumption was not affected by
different levels of dietary supplementation of riboflavin. The
supplementation of riboflavin in the diet increased (p < 0.001)
plasma riboflavin level, but the magnitude of response decreased with
age. The main component in the tissues was FAD, followed by FMN and
riboflavin. Overall, the dietary riboflavin supplementation had
highly significant (p < 0.001) effects on tissue FAD, FMN, and
riboflavin status, but the effect of supplementation was clearly
pronounced only at days 7 and 14, and thereafter the status of FAD,
FMN, and riboflavin in the tissues did not differ between
unsupplemented and supplemented birds. Neither FAD, FMN, and
riboflavin nor GSSG-RED activity correlate with the level of
supplementation. Saturation levels of riboflavin in the blood plasma
and tissues, corresponded with dietary riboflavin levels of
supplementation at 1 to 2 mg per kg. Based on the performance and
biochemical data, the dietary requirement of riboflavin for fast
growing broilers should be set at a level of 5 mg/kg. The currently
recommended allowance of 3.6 mg riboflavin per kg of ration is not
sufficient for modern breeds of broiler chickens.
Keywords
Broiler, Riboflavin, Requirement, Deficiency
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 5, © Verlag Hans Huber AG, Bern
Department of Marine Food Science, National Taiwan Ocean University, Keelung 202, Taiwan, R.O.C.
Summary
To investigate the effects of dietary cholesterol and cholic acid on plasma cholesterol levels, rats fed a cholesterol-free diet or a diet enriched in cholesterol (0.5% or 1%) with or without cholic acid supplementation were studied for 4 weeks. Although 0.5% cholesterol supplementation showed no effect on plasma total cholesterol and LDL-cholesterol levels in rats fed a diet without cholic acid treatment, the addition of dietary cholic acid caused an increase in plasma total cholesterol, LDL-cholesterol and VLDL-cholesterol levels in rats fed a cholesterol-rich diet. There was no significant change in HDL-cholesterol levels among the dietary groups. Rats fed a diet enriched in cholesterol have increased liver total lipids and total cholesterol contents. In addition, lower liver lipid peroxide concentration was found in rats fed a cholesterol-rich diet when compared with those fed the control diet. It is interesting that cholic acid supplementation led to an increase in hepatic cholesterol content and a decrease in liver lipid peroxide concentration in rats fed a cholesterol-rich diet. Results from this study suggest that dietary cholesterol and cholic acid might play an important role in regulation of lipid metabolism in rats.
Keywords
Lipoprotein cholesterol, Plasma, Rats, Cholesterol-rich diet, Cholic acid
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 5, © Verlag Hans Huber AG, Bern
1 Bio Science Laboratories, Meiji Seika
Kaisha, Ltd., Sakado-shi, Saitama, 350-02, Japan, Fax
81(Japan)-492-84-7598
2 Department of Food and Nutrition College of Human
Ecology, Seoul National University, Seoul, 151-742, Korea Fax
82(Korea)-2-884-0305
3 Department of Applied Biological Chemistry, Faculty of
Agriculture, Tohoku University, Sendai-shi, Miyagi, 981, Japan, Fax
81(Japan)-22-717-8813
Summary
We examined the effect of ingested casein phosphopeptides (CPP) on intestinal calcium (Ca) absorption and determined the minimum effective dose for enhancement of Ca absorption under conditions of marginal dietary Ca levels. Male Sprague-Dawley rats, divided upon weaning into five groups, were fed a control diet (isolated soyprotein, ISP; 20%) or a CPP diet (ISP + CPP; 20%, CPP/Ca: 0.1, 0.2, 0.35 and 1.0) for 4 weeks. All diets contained the same amounts of Ca (0.35%) and phosphorus (0.70%). The apparent Ca absorption, the retention of Ca, and the luminal soluble Ca content in the small intestine as determined at 4 weeks in the rats fed CPP diet with a weight ratio of CPP/Ca of more than 0.2 were significantly (p < 0.05) higher than those in the rats fed control diet. The wet weight, length and Ca content of the femur were not significantly different among the groups. These results indicate that the minimum effective dose of CPP for enhancement of Ca absorption is 0.7 g/kg or a weight ratio of CPP/Ca of 0.2 in the ISP diet and that CPP supplementation has the effect of significantly increasing Ca absorption at least under conditions of marginal dietary Ca levels.
Keywords
Calcium, Absorption, Casein Phosphopeptides (CPP), Rats
International Journal for Vitamin and Nutrition Research,
Band 68, 1998, Heft 5, © Verlag Hans Huber AG, Bern