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Biomedical subjects

J Leclerc

Publications and source records attributed to J Leclerc.

At least 73 records · Page 4Linked to original sources
PubMed1980

[Vitamin B1 nutritional status of the lactating rat and her litter as a function of the dietary level of thiamine].

Influence of the Dietary level of Thiamin on the Vitamin Nutritional Status of the Lactating Rat and the litter. Seven Groups of female rats which had given birth to the litters of 8 youngs (or litters adjusted to 8 youngs) were fed diets containing respectively 0.5, 1, 2, 4, 8, 16 or 32 mg/kg of thiamin. Eighteen days after littering, the thiamin content was measured in female tissues (blood, liver, carcass) or in those of the youngs (liver, carcass). Besides, the thiamin content in the stomach of the youngs was measured, 3, 7 and 14 days after birth. 1. In the females there are linear or cubic relationships between the thiamin content in the tissues and the log-concentration of the vitamin in the diet. In the liver and the carcass, it seems that the vitamin level in the tissues reaches a plateau when the dietary level is below 1 mg/kg or above 16 mg/kg. 2. On day 7th or 14th the gastric vitamin content (milk) in the youngs gradually increases, as the dietary vitamin supply does, and especially on day 14th when the dietary level of thiamin is 2 mg/kg or higher. 3. In the youngs, the organ thiamin contents markedly increase when the dietary supply rises from 1 to 8 mg/kg. Below 1 mg/kg and beyond 8 mg/kg there is a plateau. 4. These results suggest that the thiamin fixation in the offspring tissues occurs prior to the fixation in the lactating mother. The priority would be proved by the fast increase of the milk content in thiamin during the 2nd week when the vitamin dietary supply rises.

Animal Population Groups↗
PubMed1980

[Effect of methionine supplementation of a diet low in riboflavin and at 2 levels of protein on metabolism of riboflavin in the lactating rat].

Lactating female rats were fed diets A or B containing 18 and 12% of casein respectively, or similar diets but supplemented with 0.4% of methionine (diets AM or BM). The animals and their pups were sacrificed at the 18th day of lactation. Control non lactating female rats fed the same diets for the same period of time were also sacrificed. Total riboflavin and its various forms (flavin adenin dinucleotide, flavin mononucleotide + free riboflavin) were measured in various tissues as well as in the milk which was collected from the stomach of the pups after a time controlled suck. In the lactating females fed diets A and B as well as in the control animals fed the same diets the concentrations of riboflavin and of its various forms in plasma, liver and carcass are unchanged. However in group B, they are higher in milk and in tissues of the pups. These results seem to be due to a decrease in food intake by the lactating females fed diet B which results in a decrease in milk production which in turn induces a lower growth rate of the pups although the riboflavin consumption by the latter is unchanged. Addition of methionine to the diet B (diet BM) induces the same effects as diet A which contains the highest amount of proteins but addition of methionine to the diet A (diet AM) has no further incidence. Therefore the present study has not revealed any direct effect of methionine on riboflavin metabolism in lactating female rats and their pups since the effects are similar to an increase of the total protein level in the diet. In both cases they seem to be simply related to an increase of the food consumption.

Animals↗
PubMed1979

[Vitamin B2 nutritional status of pregnant rats and their offspring in relation to dietary riboflavin intake].

Four groups of gestating female rats were fed diets containing respectively 1, 2, 4, 6 mg of riboflavine per kg. Measurements of the changes in vitamin excretion as related to the dietary intake during various periods of gestation support the hypothesis that riboflavin requirement increases in the last days of gestation. On the other hand, measurements of riboflavin concentration in tissues show that, when the vitamin is given in suboptimal quantity, it is priorly fixed by the foetus. Qualitatively these results are similar to those we obtained in our corresponding study with thiamin. However, the magnitude of the changes in riboflavin urinary excretion or fixation by organs, as related to the dietary intakes, are much more limited as compared to those obtained with thiamin.

Animal Nutritional Physiological Phenomena↗
PubMed1978

[Tissue thiamine, riboflavin and vitamin B6 in the aged rat. II. Effects of vitamin supplementation in the diet on the excretion of vitamins and its tissue levels].

Nine and twenty-one months old rats fed a balanced diet were given for 5 weeks an extra supplementation in thiamine, riboflavin and vitamin B6. Control animals were given the same diet but without vitamin extra supplementation. Fecal and urinary vitamin excretions were determined during this 5 weeks period. They were shown to be less important in older rats than in younger ones. Influence of aging and vitamin supplementation on the vitamin contents of organs and tissues were studied on these animals: previous results were confirmed [see LECLERC, Ann. nutrit, Aliment., 1976, 30, 10--25]. From these results and others published elsewhere, it is conclused that in older animals there could be an increased intestinal destruction of the above mentionned vitamin although changes in vitamin metabolism can be involved too.

Aging↗
PubMed1978

[The vitamin B 1 nutritional status of the pregnant rat and its litter as a function of dietary thiamine supply].

Influence of the dietary supply in thiamine on the vitamin nutritional status of the gestating female rat and of the litter. Four groups of gestating female rats were fed diet containing respectively 2, 4, 6, 8 mg of thiamine par kg. In every group, urinary excretion of thiamine was found to be stable up to the 16th day of gestation and then to decrease markedly during the 5 last days. This result and those concerning the changes in vitamin excretion, as related to the dietary intake, support the hypothesis that thiamine requirement is strongly higher at the end of the gestating period. On the other hand, measurements of thiamine concentration in tissues show that, when thiamine is given in suboptimal quantity, it is priorly fixed by the foetus at the expense of the maternal organs particulary of the liver.

Animal Nutritional Physiological Phenomena↗
PubMed1977

[Thiamine, riboflavin and vitamin B6 contents of organs in the aged rat. I. Effect of vitamin supplementation administered in drinking water].

Respectualy ten and twenty-two months old rats, fed an equilibrated diet, were given daily and for one month an extra supplementation of thiamine, riboflavin and vitamin B6 in drinking water. Control animals of the same age were fed identical diets but without vitamin extra supplementation. Vitamin contents of organs (liver, heart, kidneys, spleen, lungs, brain) were determined in order to evaluate both the influence of aging and of vitamin supplementation. Twenty-three months old rats show lower values of thiamin contents (except in liver and brain), riboflavin contents (except in heart and spleen) and vitamin B6 contents (except in heart, lungs and brain) than younger rats. Vitamin extra-supplementation reduces some of these differences: thiamine contents in heart, kidneys and spleen, riboflavin contents in brain, vitamin B6 contents in kidneys and spleen. In all other cases, the extra-supplementation has no effect. Therefore, it seems that the decrease in vitamin contents in organs of old rats is, in many cases an unavoidable consequence of aging.

Age Factors↗
PubMed1975

[Influence of protein-enriched food on tissue vitamin content in pregnant and lactating rats].

Two groups of female rats were fed, during gestation and until weaning of their pups, diets containing respectively 18% (normal protein diet) and 27% (high protein diet) by weight of casein. Two control groups of female rats were fed the same diet. Thiamin, riboflavin and vitamin B6 contents were measured in: - liver and carcass of the mothers before and immediately after delivery or at weaning (21st day), - whole body of the new born rats or in liver and carcass of 21 days old pups. - liver and carcass of the control animals. The high protein diet, as compared to the normal diet, gives the following results: 1) There is no variation of the thiamin content in control animals, female rats at delivery, new born rats. However, at weaning, carcasses of mothers and pups (mainly liver) are enriched in thiamin. 2) On the other hand, riboflavin content in tissues increases in control animals (liver and carcass), in mothers before and after delivery (carcass) but particularly in mothers at the end of lactation (liver and carcass) and it is also the case with pups at weaning (carcass). Only in new born rats do both diets have the same effect. 3)The influence of the high protein diet on vitamin B6 content in tissues is complex. The content is not modified in control animals, in mothers at delivery and in new born rats. At the end of lactation (mothers) and at weaning (pups), the vitamin B6 content increases in liver but strongly decreases in carcass.

Animals↗