Use of the RatLoft decreases pup mortality in lactating mice.

Lactating mice in laboratory conditions are thought to be under considerable stress. Dams may manifest this stress through a decrease in milk yield and/or increase in infanticide. The purpose of this study was to examine the effect of access to an environmental enrichment device called the RatLoft on milk yield, circulating serotonin, and pup mortality using both wild-type mice and mice genetically deficient in tryptophan hydroxylase 1 (TPH1(-/-); the rate-limiting enzyme in the non-neuronal serotonin synthesis pathway).

Octanoate and nonaoate oxidation increases 50-80% over the first two days of life in piglet triceps brachii and gracilis muscle strips.

An in vitro muscle strip incubation system was developed to measure the rate of catabolism of 1 mmol/L [1-(14)C]octanoate, 1 mmol/L [1-(14)C]nonanoate, 1 mmol/L [9-(14)C]nonanoate, and 10 mmol/L [U-(14)C]glucose by measuring the recovery of (14)CO(2). Muscle strips (13 mm × 1.5 mm, ~50 mg) were isolated from triceps brachii and gracilis muscles of newborn and 2-d-old, small (<950 g) and large (>1450 g) piglets.

Blood D-(-)-3-hydroxybutyrate concentrations after oral administration of trioctanoin, trinonanoin, or tridecanoin to newborn rhesus monkeys (Macaca mulatta).

Premature newborn infants are born with limited stores of glycogen and fat. Energy, such as medium-chain triglycerides (MCT), which can spare the use of body protein as metabolic energy, may be beneficial. This study compares MCT containing C8, C9, or C10 fatty acids as oral sources of energy for newborn rhesus monkeys (Macaca mulatta).

Role of S-adenosylmethionine, folate, and betaine in the treatment of alcoholic liver disease: summary of a symposium.

This report is a summary of a symposium on the role of S-adenosylmethionine (SAM), betaine, and folate in the treatment of alcoholic liver disease (ALD), which was organized by the National Institute on Alcohol Abuse and Alcoholism in collaboration with the Office of Dietary Supplements and the National Center for Complementary and Alternative Medicine of the National Institutes of Health (Bethesda, MD) and held on 3 October 2005. SAM supplementation may attenuate ALD by decreasing oxidative stress through the up-regulation of glutathione synthesis, reducing inflammation via the down-regulation of tumor necrosis factor-alpha and the up-regulation of interleukin-10 synthesis, increasing the ratio of SAM to S-adenosylhomocysteine (SAH), and inhibiting the apoptosis of normal hepatocytes and stimulating the apoptosis of liver cancer cells. Folate deficiency may accelerate or promote ALD by increasing hepatic homocysteine and SAH concentrations; decreasing hepatic SAM and glutathione concentrations and the SAM-SAH ratio; increasing cytochrome P4502E1 activation and lipid peroxidation; up-regulating endoplasmic reticulum stress markers, including sterol regulatory element-binding protein-1, and proapoptotic gene caspase-12; and decreasing global DNA methylation.

Unique aspects of lysine nutrition and metabolism.

Lysine nutrition is unique among indispensable amino acids in that it can be conserved and can be fed 12 h out of phase (delayed supplement) with the other dietary amino acids. In piglets, high levels (2-6%) of L-lysine added to a 10% protein diet can be tolerated without obvious detrimental effects. In both rat and piglet liver preparations, the first enzyme in the saccharopine-dependent pathway of lysine catabolism, lysine alpha-ketoglutarate reductase (LKR), is found only in the mitochondrial matrix.

Consideration of betaine and one-carbon sources of N5-methyltetrahydrofolate for use in homocystinuria and neural tube defects.

A major focus in attempts to ameliorate homocystinuria and neural tube defects is supplementation of the diet with B vitamins. The metabolic defect in these cases may be due in part to a deficiency of methyl groups. B vitamin supplementation supports the need for enzyme cofactors but cannot provide substrate in the form of methyl groups.

The contribution of body protein to the supply of energy in starved newborn piglets is not preferentially suppressed by intravenous provision of glucose and fat.

Newborn piglets were used to study body protein preservation because it is critical to the survival of premature infants. Quantitative estimates of endogenous fuel use were obtained from 12 to 72 h of age in male piglets. Of the 40 piglets used (1300 +/- 205 g, mean +/- SD), 16 served as a 12-h-old body composition reference (R), 16 were starved (S) and received water only, and 8 received supplemental energy (E), obtaining 70% [210 kJ/(kg x d)] of their resting energy requirement as an i.

Recovery of (15)n in the body, urine, and gas phase of piglets infused intravenously with (15)n L-alanine from 12-72 hours of age.

Previous studies of nitrogen metabolism provided evidence suggesting that nitrogen excretory product(s) not measured by standard methods of analysis escape detection. To determine whether (15)N could be recovered quantitatively in the body, urine, or expired gas, newborn piglets (n = 16; 1.47 +/- 0.

Comparison of total body urea production potential with total body carbamoyl phosphate synthetase (CPS-1) activity in newborn piglets infused with alanine at 50% of resting energy expenditure for 36 hours.

The calculated rate of urea production [U(p); mmol urea/(h. kg(0. 75))], based on urinary urea-N (UUN) excretion and changes in total body urea-N, was compared with the calculated total body V(max) of carbamoyl phosphate synthetase (CPS-1) of 24 neonatal piglets from four treatments as follows: 6 h baseline control (n = 8), 18 h of alanine intravenously (IV) at 50% of resting energy expenditure (REE; n = 4), 36 h of alanine IV at 50% of REE (n = 6), or 36 h of glucose IV at 50% of REE (n = 6).

Urea production is increased in neonatal piglets infused with alanine at 25, 50, and 75% of resting energy needs .

To study the ability of neonatal piglets to metabolize a nitrogen load and excrete it as urea, 12 newborn piglets, 6 small (0.99 +/- 0. 16 kg; expt.

Effect of sensory stimuli on huddling behavior of pigs.

Two experiments involving pigs at 1, 3, and 8 d of age were conducted to 1) compare huddling between littermates and nonlittermates, 2) study the ability of pigs to distinguish an anesthetized piglet from a piglet-shaped object, and 3) explore the importance of physical contact between pigs on huddling behavior. Experiments were conducted in an enclosed rectangular aluminum test chamber having pressure sensors beneath floor panels to detect test pig location. Test objects were placed on a platform at one end of the chamber and test pig location was monitored during a 45 min trial.

The effect of thermal environment and age on neonatal pig behavior.

Three experiments were conducted to evaluate the ability of a radiant environment and the presence of a littermate to attract pigs during the first 3 d of age. The effect of stimuli on pig movement was studied in an enclosed rectangular aluminum test chamber containing four similar sections that were heated independently. In Exp.

The effect of farrowing crate heat lamp location on sow and pig patterns of lying and pig survival.

Three experiments were conducted to study sow and pig behavior during the 1st 3 d after birth and pig survival during the 1st 2 wk after farrowing. In Exp. 1, 23 sows were housed in conventional farrowing crates that were divided into five sections: a .

Mitochondrial lysine uptake limits hepatic lysine oxidation in rats fed diets containing 5, 20 or 60% casein.

Sixty male Sprague-Dawley rats were randomly allotted to receive diets containing 5, 20 or 60% casein. Rats had access to the diet only during the initial 8 h of the daily 12-h dark period. Hepatic mitochondrial lysine uptake, lysine alpha-ketoglutarate reductase (LKR) and saccharopine dehydrogenase (SacD) activities, and in vitro lysine oxidation (LOX) were measured 0, 6, 12, 18 and 24 h after the start of the dark period.

Rates of lysine catabolism are inversely related to rates of protein synthesis when measured concurrently in adult female rats induced to grow at different rates.

To test the effect of changes in the rate of protein synthesis on amino acid oxidation, both were studied concurrently in individual 200-g female Sprague-Dawley rats. In a growth trial (Experiment 1), recombinant bovine somatotropin (rbST) was injected subcutaneously (0, 2 or 12 mg/d) over 6 d (n = 4 rats per rbST level). Weight gain increased with rbST level (P < 0.

Feeding diets containing high levels of milk products or cellulose decrease urease activity and ammonia production in rat intestine.

Three studies were done to determine the effect of feeding diets containing high levels of a readily fermentable carbohydrate (lactose in milk or yogurt, or pure lactose) or an undigestible, unfermentable diluent (alpha-cellulose) on urease (EC 3.5.1.

Synthesis of [9-14C]nonanoic acid via 2-thienyl(14CH3)(cyano)cuprate and its oxidation by newborn piglet muscle strips.

To determine if newborn piglet muscle could oxidize propionyl-CoA formed by catabolism of odd-chain fatty acids, an odd-chain fatty acid labeled in the terminal three carbons was needed. The synthetic scheme described is based upon the displacement of a primary alkyl iodide, ethyl 8-iodooctanoate, by a [14C]methyl group via an activated 2-thienyl(14CHa)(cyano)cuprate intermediate, forming ethyl [9-14C]nonanoate. Ethyl [9-14C]nonanoate was hydrolyzed in 6 N KOH and [9-14C]nonanoic acid recovered by ion-exchange chromatography.

Efficiency of lysine or threonine retention in growing rats fed diets limiting in either lysine or threonine.

Over a 21-d experiment, the efficiency of lysine and threonine retention was determined in 80 male Sprague-Dawley rats (65.9 +/- 0.3 g, means +/- SE) fed purified diets containing an amino acid mix limiting in either lysine or threonine.

Recombinant bovine somatotropin decreases hepatic amino acid catabolism in female rats.

The effect of recombinant bovine somatotropin (rbST) on hepatic amino acid catabolism in female rats was investigated. Daily injections of rbST for 5 d decreased liver homogenate lysine alpha-ketoglutarate reductase (EC 1.5.

Contribution of D-(-)-3-hydroxybutyrate to the energy expenditure of neonatal pigs.

In vivo oxidation rate of arterially infused D-(-)-3-hydroxybutyrate (3HB) was measured in 1-2-d-old-piglets. Twelve piglets (1.4 kg) were randomly assigned to a 12 h continuous infusion of 3HB at 19.

Diminishing returns in weight, nitrogen, and lysine gain of pigs fed six levels of lysine from three supplemental sources.

Diminishing returns responses to increments of lysine intake were evaluated in 82 crossbred barrows (10.2 +/- SE = .31 kg) fed one of six concentrations of lysine expressed as 55, 80, 90, 100, 115, or 140% of a concentration (10.

Lysine-alpha-ketoglutarate reductase and saccharopine dehydrogenase are located only in the mitochondrial matrix in rat liver.

In rat liver, comparisons of marker enzyme activities (beta-hexosaminidase, lysosomes; catalase, peroxisomes; cytochrome oxidase, mitochondrial-inner membrane; monoamine oxidase, mitochondrial outer membrane; ornithine aminotransferase, mitochondrial matrix) show that lysine-alpha-ketoglutarate reductase and saccharopine dehydrogenase, the initial enzymes of saccharopine-dependent lysine degradation, are found only in the mitochondrial matrix. These results are consistent with obligatory uptake of lysine into the matrix for lysine catabolism and raise the possibility that lysine transport into the mitochondrion may control lysine degradation.

Role of protein synthesis in amino acid catabolism.

Except for branched chain amino acids, the site of indispensable amino acid degradation is the liver. Location of amino acid degradation capacity in a single organ may play an important role in the reutilization of amino acids derived from protein turnover. The importance of preferential utilization of amino acids for protein synthesis on catabolism of amino acids is demonstrated in two ways.