Circadian Feeding Pattern in Pregnant Rats Fed Three Levels of Protein

Hitier, Y; Champigny, O; Homayoon, P; Bourdel, G

doi:10.1159/000176555

Cited by 24 publications

(15 citation statements)

References 15 publications

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“…In connection with the growth of these animals, it is important to determine whether their utilization efficiencies of nutrients increase. Previously, we (1) and others (2) observed that the products of conception grew markedly during late pregnancy in normal pregnant rats, despite terminal anorexia. Thus, special attention was focussed on the utilization efficiency of metabolizable energy in this period.…”

Section: Discussionmentioning

confidence: 74%

Maintenance energy requirement in pregnant rats and net energetic efficiency for fetal growth during late pregnancy.

Imai

Ohnaka

Ondani

et al. 1986

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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SummaryThe maintenance energy requirement (MEm) of pregnant rats and net energetic efficiency for fetal growth during late pregnancy were examined by regression analysis. Pregnant rats, weighing about 180 g, were fed on 20% casein diet during early-mid pregnancy and then divided into three groups ad libitum-fed, 50% food restricted, or starved. A linear relation between the energy balance (Y, kcal/100g BW/day) and the metabolizable energy intake (X, kcal/100g BW/day) was obtained as Y=0.81 X-14.83 (n: 17, r=+0.99, p<0.001).The X intercept, MEm, was calculated to be 18.31kcal/100g BW/day. Pregnant animals fed ad libitum retained 6.1 and 1.1 kcal of energy daily in their conceptuses and their own body, respectively, during late pregnancy. Assuming that the net efficiency of maternal energy deposition is equal to that for size and age-matched nonpregnant rats, the net energetic efficiency for fetal growth was calculated to be 82%. This value was very close to the net efficiency for weanling rats reported previously, suggesting that the net energetic efficiency for maximum growth in well-nourished rats is about 82%.

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Section: Discussionmentioning

confidence: 74%

Maintenance energy requirement in pregnant rats and net energetic efficiency for fetal growth during late pregnancy.

Imai

Ohnaka

Ondani

et al. 1986

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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show abstract

“…In the present study as well as in earlier studies in which obligatory nitrogen losses were examined, animals were fed a protein-free diet ad libitum and became anorexic (11). On the contrary, in most of experiments in humans, sufficient dietary energy was provided to maintain the body weight.…”

Section: Discussionmentioning

confidence: 88%

Obligatory Nitrogen Losses in Pregnant Rats with Special Reference to Estimation of Net Protein Utilization.

Sakamoto

Mori

Ohnaka

et al. 1992

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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SummaryFor estimation of net protein utilization of dietary proteins during pregnancy, obligatory nitrogen losses were measured in protein deficient rats in which pregnancy was maintained by administration of ovarian steroids. On shift from normal to protein-free diet, urinary nitrogen, expressed as mg/day or mg/100g BW per day, decreased initially rapidly and then gradually during the first two weeks in both pregnant and nonpregnant rats. However, urinary endogenous nitrogen increased during the final week of pregnancy, whereas it continued to decrease in nonpregnant controls. The endogenous urinary nitrogen excretions during early-mid and late pregnancies were significantly higher in preg nant rats (666mg/15days and 234mg/6days, respectively) than in nonpregnant animals (585mg/15days and 153mg/6days, respectively), indicating pregnancy-induced protein hypercatabolism. The metabolic fecal nitrogen excretions in pregnant and nonpregnant rats were compara ble. In pregnant rats, a protein-free diet resulted in decrease of basal energy expenditure, from 24kcal/day on day 1 to about 15kcal/day on days 16, 19 and 22 of pregnancy. Thus, the ratio of endogenous urinary nitrogen to basal energy expenditure increased in late pregnancy, indicat ing that "the law of a constant relationship of minimal nitrogen and energy output" is not applicable to the pregnant animals. We discuss which values for obligatory nitrogen loss should be used for estimating the net utilization efficiency of dietary proteins in pregnancy. Key Words endogenous urinary nitrogen, metabolic fecal nitrogen, en dogenous nitrogen/BMR, pregnancy induced hypercatabolism, NPU, pro tein-free diet Obligatory urinary and fecal excretions of nitrogen have been determined in various animals, including humans, to determine the minimum nitrogen require ments and/or to assess the net utilization of dietary proteins (NPU) (1). Results 493

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“…Thus, we think that the variations in the blood amino acid concentrations in the mother could be understood, in part, as a consequence of the transference rate of substrates, mainly for protein synthesis, to the foetuses and pups, and also as a consequence of important met abolic adaptations which occur in the moth er, e.g., the development of hyperphagia, es pecially during lactation [17] and the appear ance of different mechanisms for saving ni trogen [18], During mid-gestation, the tendency of the amino acid cellular content to decrease, mainly accounted for by some important ni trogen carrier amino acids (Ala, Glu+Gln), should not be related to the metabolic weight of the foetoplacental unit, since it is negligible during this period [19], Hyperphagia has al ready increased [17], and experiments are currently under way to ascertain whether ni trogen-saving mechanisms are already present in the mother. However, cellular de pletion should be related to an increased amino acid output to the plasma fraction in order to allow supply to the maternal tis sues.…”

Section: Discussionmentioning

confidence: 99%

Blood Amino Acid Compartmentalization during Pregnancy and Lactation in the Rat

López-Tejero¹,

Pastor-Anglada²,

Remesar³

1986

Ann Nutr Metab

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The blood amino acid compartmentalization during pregnancy and lactation of the rat have been studied. Cellular amino acid levels are similar to those of the plasmatic fraction. Important generalized decreases are detected on days 12 and 21 of the pregnancy; Glu + G1n, Ala and essential and semiessential amino acids being the most affected. During lactation, after a transient phase on day 1 after delivery, there is a generalized increase in blood levels, especially in the plasma fraction, that affects the whole essential values. The different patterns shown by amino acids during pregnancy and lactation confirm that the measurement of plasmatic levels underestimates the actual capacity of whole blood to transport amino acids.

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Circadian Feeding Pattern in Pregnant Rats Fed Three Levels of Protein

Cited by 24 publications

References 15 publications

Maintenance energy requirement in pregnant rats and net energetic efficiency for fetal growth during late pregnancy.

Maintenance energy requirement in pregnant rats and net energetic efficiency for fetal growth during late pregnancy.

Obligatory Nitrogen Losses in Pregnant Rats with Special Reference to Estimation of Net Protein Utilization.

Blood Amino Acid Compartmentalization during Pregnancy and Lactation in the Rat

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