Chronic parenteral nutrition induces hepatic inflammation, steatosis, and insulin resistance in neonatal pigs.

Prematurity and overfeeding in infants are associated with insulin resistance in childhood and may increase the risk of adult disease. Total parenteral nutrition (TPN) is a major source of infant nutritional support and may influence neonatal metabolic function. Our aim was to test the hypothesis that TPN induces increased adiposity and insulin resistance compared with enteral nutrition (EN) in neonatal pigs.

Leucine supplementation of a low-protein meal increases skeletal muscle and visceral tissue protein synthesis in neonatal pigs by stimulating mTOR-dependent translation initiation.

Protein synthesis and eukaryotic initiation factor (eIF) activation are increased in skeletal muscle of neonatal pigs parenterally infused with amino acids. Leucine appears to be the most effective single amino acid to trigger these effects. To examine the response to enteral leucine supplementation, overnight food-deprived 5-d-old pigs were gavage fed at 0 and 60 min a: 1) low-protein diet (LP); 2) LP supplemented with leucine (LP+L) to equal leucine in the high-protein diet (HP); or 3) HP diet.

Plasma arginine and ornithine are the main citrulline precursors in mice infused with arginine-free diets.

Dietary arginine is the main dietary precursor for citrulline synthesis, but it is not known if other precursors can compensate when arginine is absent in the diet. To address this question, the contributions of plasma and dietary precursors were determined by using multitracer protocols in conscious mice infused i.g.

Validation of cross-sectional time series and multivariate adaptive regression splines models for the prediction of energy expenditure in children and adolescents using doubly labeled water.

Accurate, nonintrusive, and inexpensive techniques are needed to measure energy expenditure (EE) in free-living populations. Our primary aim in this study was to validate cross-sectional time series (CSTS) and multivariate adaptive regression splines (MARS) models based on observable participant characteristics, heart rate (HR), and accelerometer counts (AC) for prediction of minute-by-minute EE, and hence 24-h total EE (TEE), against a 7-d doubly labeled water (DLW) method in children and adolescents. Our secondary aim was to demonstrate the utility of CSTS and MARS to predict awake EE, sleep EE, and activity EE (AEE) from 7-d HR and AC records, because these shorter periods are not verifiable by DLW, which provides an estimate of the individual's mean TEE over a 7-d interval.

Body size, body composition, and metabolic profile explain higher energy expenditure in overweight children.

Lower relative rates of energy expenditure (EE), increased energetic efficiency, and altered fuel utilization purportedly associated with obesity have not been demonstrated indisputably in overweight children. We hypothesized that differences in energy metabolism between nonoverweight and overweight children are attributable to differences in body size and composition, circulating thyroid hormones, sympathetic nervous system, and adrenomedullary activity. A total of 836 Hispanic children, 5-19 y old, participated in 24-h calorimetry, anthropometric, and dual-energy X-ray absorptiometry measurements.

Extensive gut metabolism limits the intestinal absorption of excessive supplemental dietary glutamate loads in infant pigs.

Glutamate (Glu) is a major intestinal oxidative fuel, key neurotransmitter, and may be a useful dietary supplement to augment health of the infant gut. We quantified the metabolic fate of various supplemental dietary Glu intakes in young pigs surgically implanted with vascular, intraduodenal (ID), or intragastric (IG) catheters and a portal blood flow probe. Piglets were acutely fed a range of dietary Glu intakes using a basal milk formula (100%) supplemented with varying amounts of monosodium Glu (up to 400%) via ID or IG routes.

Total energy expenditure and physical activity level of lactating Mesoamerindians.

Energy-sparing mechanisms may be elicited to meet increased energy requirements imposed by lactation on women who reside in poor, rural communities in developing countries. The objectives of this study were to measure total energy expenditure and its components, basal and activity energy expenditure, and to investigate their relationships with lactation performance in a total of 40 rural Mesoamerindians stratified according to postpartum body mass index. Total energy expenditure and fat-free mass were measured by the doubly labeled water method, and basal metabolic rate was determined by indirect calorimetry at 3 and 6 mo postpartum.

Chronic protein deficiency differentially affects the kinetics of plasma proteins in young pigs.

The use of plasma protein concentrations to assess protein-nutritional status has been questioned because concentrations and kinetics are affected by factors other than protein intake. To determine the effect of protein deficiency on plasma protein concentration and synthesis, two groups of four piglets consumed diets containing either 20 or 3% protein. After 8 wk, 2H3-leucine was infused intravenously to measure the fractional and absolute synthesis rates (FSR and ASR) of albumin, transferrin, retinol binding protein (RBP), transthyretin (TTR), a new peptide called TTR2, the high density apolipoprotein (HDL-apoA-1), fibrinogen, and haptoglobin.

Chronic low protein intake reduces tissue protein synthesis in a pig model of protein malnutrition.

To determine the effect of severe chronic protein deficiency on protein synthesis in different tissues and total protein in plasma, and on plasma biochemical constituents involved in amino acid metabolism, we fed diets containing either 20 or 3% protein to two groups of four age-matched piglets. After consuming the diets for 8 wk, the pigs received a primed-constant infusion of 2 H3-leucine for 8 h to measure the fractional synthesis rates (FSR) of tissue protein and total protein in plasma. Plasma urea and amino acid concentrations, particularly indispensable amino acids, were significantly lower in protein-deficient pigs.