scholarly journals Urea synthesis and leucine turnover in growing pigs: changes during 2 d following the addition of carbohydrate or fat to the diet

1987 ◽  
Vol 58 (2) ◽  
pp. 301-311 ◽  
Author(s):  
P. J. Reeds ◽  
M. F. Fuller ◽  
A. Cadenhead ◽  
S. M. Hay
Keyword(s):  
Blood Glucose ◽  
Plasma Insulin ◽  
Specific Radioactivity ◽  
Growing Pigs ◽  
Whole Body ◽  
Total Amino Acid ◽  
Urea Synthesis ◽  
Hormonal Changes ◽  
Plasma Urea ◽  
Body Protein

1. Studies have been made of the time-sequence of protein metabolic and hormonal changes following an abrupt increase in carbohydrate or fat intake. [3H]leucine and [14C]urea were infused for 72 h, via the aorta, into fourteen female pigs (30–38 kg body-weight). At 24 h after the start of the infusion their feed was either changed to one of two isonitrogenous diets containing additional starch (group BS, five animals) or fat (group BF, five animals), or remained unaltered (group BB, four animals). The distribution space of urea was measured by the dilution of a single dose of [14C]urea given both 48 h before and 48 h after the change in diet. The changes in the concentration and specific radioactivity of blood leucine were used to infer changes in protein turnover and those of plasma urea to measure total amino acid catabolism. The concentrations of blood glucose and plasma insulin and cortisol were also measured at approximately two-hourly intervals for the 48 h period following the change in diet.2. Within 4 h of either change in diet blood leucine concentration was lowered and the leucine specific radioactivity was raised above that in group BB, but after 24 h both the concentration and specific radioactivity of leucine returned to values similar to those in group BB. Eventually the blood leucine specific radioactivity was slightly but not significantly reduced below that of group BB.3. The addition of starch to the diet significantly reduced the synthesis and concentration of urea within 4 h but, although the addition of fat to the diet eventually lowered the urea concentration and synthesis, both changes were delayed for 18–24 h.4. In group BS plasma glucose and insulin rose after the addition of starch, but after 24–36 h both returned to values that were the same as those in the animals that received the same diet throughout (group BB). The addition of fat to the diet altered neither blood glucose nor plasma insulin concentrations. The addition of either carbohydrate or fat to the diet eventually reduced pIasma cortisol concentrations, but the change did not occur until 24 h after the change in diet.5. The results suggest that alterations in non-protein energy supply exert their immediate effect on the degradation of whole-body protein. They do not exclude the possibility that these early changes may reflect opposing changes at different sites. The results also suggest that the rate of urea synthesis may be controlled by the balance between the concentrations of insulin and cortisol, but that under the conditions of these experiments there was little relation between these hormones and the turnover of body protein as measured by the turnover of blood leucine.

scholarly journals Effects of the amount and quality of dietary protein on nitrogen metabolism and protein turnover of pigs

1987 ◽  
Vol 58 (2) ◽  
pp. 287-300 ◽  
Author(s):  
M. F. Fuller ◽  
P. J. Reeds ◽  
A. Cadenhead ◽  
B. Seve ◽  
T. Preston
Keyword(s):  
Dietary Protein ◽  
Protein Turnover ◽  
Growing Pigs ◽  
Whole Body ◽  
Urea Synthesis ◽  
Total N ◽  
Plasma Urea ◽  
Body Protein ◽  
N Retention

1. The interrelations between protein accretion and whole-body protein turnover were studied by varying the quantity and quality of protein given to growing pigs.2. Diets with 150 or 290g lysine-deficient protein/kg were given in hourly meals, with or without lysine supplementation, to female pigs (mean weight 47 kg).3. After the animals were adapted to the diets, a constant infusion of [14C]urea was given intra-arterially for 30 h, during the last 6 h of which an infusion of [4,5-3H] leucine was also infused at a constant rate. At the same time, yeast-protein labelled with15N was given in the diet for 50 h.4. The rate of urea synthesis was estimated from the specific radioactivity (SR) of plasma urea. The rate of leucine flux was estimated from the SR of plasma leucine. The irrevocable breakdown of leucine was estimated from the3H-labelling of body water. Total N flux was estimated from the16N-labelling of urinary urea.5. Addition of lysine to the low-protein diet significantly increased N retention, with a substantial reduction in leucine breakdown, but there was no significant change in the flux of leucine or of total N.6. Increasing the quantity of the unsupplemented protein also increased N retention significantly, with concomitant increases in leucine breakdown and in the fluxes of leucine and of total N.7. It is concluded that a doubling of protein accretion brought about by the improvement of dietary protein quality is not necessarily associated with an increased rate of whole-body protein turnover.

scholarly journals Modulation of the gut microbiota with antibiotic treatment suppresses whole body urea production in neonatal pigs

2013 ◽  
Vol 304 (3) ◽  
pp. G300-G310 ◽  
Author(s):  
Patrycja Puiman ◽  
Barbara Stoll ◽  
Lars Mølbak ◽  
Adrianus de Bruijn ◽  
Henk Schierbeek ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Gut Microbiota ◽  
Whole Body ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Urea Synthesis ◽  
Plasma Urea ◽  
Body Protein ◽  
Neonatal Pigs

We examined whether changes in the gut microbiota induced by clinically relevant interventions would impact the bioavailability of dietary amino acids in neonates. We tested the hypothesis that modulation of the gut microbiota in neonatal pigs receiving no treatment (control), intravenously administered antibiotics, or probiotics affects whole body nitrogen and amino acid turnover. We quantified whole body urea kinetics, threonine fluxes, and threonine disposal into protein, oxidation, and tissue protein synthesis with stable isotope techniques. Compared with controls, antibiotics reduced the number and diversity of bacterial species in the distal small intestine (SI) and colon. Antibiotics decreased plasma urea concentrations via decreased urea synthesis. Antibiotics elevated threonine plasma concentrations and turnover, as well as whole body protein synthesis and proteolysis. Antibiotics decreased protein synthesis rate in the proximal SI and liver but did not affect the distal SI, colon, or muscle. Probiotics induced a bifidogenic microbiota and decreased plasma urea concentrations but did not affect whole body threonine or protein metabolism. Probiotics decreased protein synthesis in the proximal SI but not in other tissues. In conclusion, modulation of the gut microbiota by antibiotics and probiotics reduced hepatic ureagenesis and intestinal protein synthesis, but neither altered whole body net threonine balance. These findings suggest that changes in amino acid and nitrogen metabolism resulting from antibiotic- or probiotic-induced shifts in the microbiota are localized to the gut and liver and have limited impact on whole body growth and anabolism in neonatal piglets.

Somatotropin increases protein balance by lowering body protein degradation in fed, growing pigs

2000 ◽  
Vol 278 (3) ◽  
pp. E477-E483 ◽  
Author(s):  
Rhonda C. Vann ◽  
Hanh V. Nguyen ◽  
Peter J. Reeds ◽  
Douglas G. Burrin ◽  
Marta L. Fiorotto ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Growing Pigs ◽  
Whole Body ◽  
Plasma Urea ◽  
Body Protein ◽  
Fed State ◽  
Protein Deposition ◽  
Leucine Oxidation ◽  
Urea Production

Somatotropin (ST) administration enhances protein deposition in well-nourished, growing animals. To determine whether the anabolic effect is due to an increase in protein synthesis or a decrease in proteolysis, pair-fed, weight-matched (∼20 kg) growing swine were treated with porcine ST (150 μg ⋅ kg− 1 ⋅ day− 1, n = 6) or diluent ( n = 6) for 7 days. Whole body leucine appearance (Ra), nonoxidative leucine disposal (NOLD), urea production, and leucine oxidation, as well as tissue protein synthesis (Ks), were determined in the fed steady state using primed continuous infusions of [13C]leucine, [13C]bicarbonate, and [15N2]urea. ST treatment increased the efficiency with which the diet was used for growth. ST treatment also increased plasma insulin-like growth factor I (+100%) and insulin (+125%) concentrations and decreased plasma urea nitrogen concentrations (−53%). ST-treated pigs had lower leucine Ra (−33%), leucine oxidation (−63%), and urea production (−70%). However, ST treatment altered neither NOLD nor Ks in the longissimus dorsi, semitendinosus, or gastrocnemius muscles, liver, or jejunum. The results suggest that in the fed state, ST treatment of growing swine increases protein deposition primarily through a suppression of protein degradation and amino acid catabolism rather than a stimulation of protein synthesis.

Measurement of protein turnover in the small intestine of lambs. 2. Effects of feed intake

1997 ◽  
Vol 128 (2) ◽  
pp. 233-246 ◽  
Author(s):  
S. A. NEUTZE ◽  
J. M. GOODEN ◽  
V. H. ODDY
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Small Intestine ◽  
Experimental Model ◽  
Feed Intake ◽  
Protein Turnover ◽  
Jugular Vein ◽  
Specific Radioactivity ◽  
Whole Body ◽  
Body Protein

This study used an experimental model, described in a companion paper, to examine the effects of feed intake on protein turnover in the small intestine of lambs. Ten male castrate lambs (∼ 10 months old) were offered, via continuous feeders, either 400 (n = 5) or 1200 (n = 5) g/day lucerne chaff, and mean experimental liveweights were 28 and 33 kg respectively. All lambs were prepared with catheters in the cranial mesenteric vein (CMV), femoral artery (FA), jugular vein and abomasum, and a blood flow probe around the CMV. Cr-EDTA (0·139 mg Cr/ml, ∼ 0·2 ml/min) was infused abomasally for 24 h and L-[2,6-3H]phenylalanine (Phe) (420±9·35 μCi into the abomasum) and L-[U-14C]phenylalanine (49·6±3·59 μCi into the jugular vein) were also infused during the last 8 h. Blood from the CMV and FA was sampled during the isotope infusions. At the end of infusions, lambs were killed and tissue (n = 4) and digesta (n = 2) samples removed from the small intestine (SI) of each animal. Transfers of labelled and unlabelled Phe were measured between SI tissue, its lumen and blood, enabling both fractional and absolute rates of protein synthesis and gain to be estimated.Total SI mass increased significantly with feed intake (P < 0·05), although not on a liveweight basis. Fractional rates of protein gain in the SI tended to increase (P = 0·12) with feed intake; these rates were −16·2 (±13·7) and 23·3 (±15·2) % per day in lambs offered 400 and 1200 g/day respectively. Mean protein synthesis and fractional synthesis rates (FSR), calculated from the mean retention of 14C and 3H in SI tissue, were both positively affected by feed intake (0·01 < P < 0·05). The choice of free Phe pool for estimating precursor specific radioactivity (SRA) for protein synthesis had a major effect on FSR. Assuming that tissue free Phe SRA represented precursor SRA, mean FSR were 81 (±15) and 145 (±24) % per day in lambs offered 400 and 1200 g/day respectively. Corresponding estimates for free Phe SRA in the FA and CMV were 28 (±2·9) and 42 (±3·5) % per day on 400 g/day, and 61 (±2·9) and 94 (±6·0) on 1200 g/day. The correct value for protein synthesis was therefore in doubt, although indirect evidence suggested that blood SRA (either FA or CMV) may be closest to true precursor SRA. This evidence included (i) comparison with flooding dose estimates of FSR, (ii) comparison of 3H[ratio ]14C Phe SRA in free Phe pools with this ratio in SI protein, and (iii) the proportion of SI energy use associated with protein synthesis.Using the experimental model, the proportion of small intestinal protein synthesis exported was estimated as 0·13–0·27 (depending on the choice of precursor) and was unaffected by feed intake. The contribution of the small intestine to whole body protein synthesis tended to be higher in lambs offered 1200 g/day (0·21) than in those offered 400 g/day (0·13). The data obtained in this study suggested a role for the small intestine in modulating amino acid supply with changes in feed intake. At high intake (1200 g/day), the small intestine increases in mass and CMV uptake of amino acids is less than absorption from the lumen, while at low intake (400 g/day), this organ loses mass and CMV uptake of amino acids exceeds that absorbed. The implications of these findings are discussed.

scholarly journals The allometric partition of whole body protein in lean fraction of growing pigs using information from three different datasets

2007 ◽  
Vol 6 (sup1) ◽  
pp. 357-359
Author(s):  
S. Schiavon ◽  
C. Ceolin ◽  
F. Tagliapietra ◽  
L. Bailoni ◽  
A. Piva
Keyword(s):  
Growing Pigs ◽  
Whole Body ◽  
Body Protein

Plasma insulin concentrations and amino acid turnover in Merino sheep with high or low fleece weight

2004 ◽  
Vol 55 (8) ◽  
pp. 833 ◽  
Author(s):  
N. R. Adams ◽  
S. M. Liu ◽  
J. R. Briegel ◽  
M. J. Thompson
Keyword(s):  
Amino Acids ◽  
Plasma Insulin ◽  
Plasma Concentrations ◽  
Amino Nitrogen ◽  
Whole Body ◽  
Metabolic Demand ◽  
Body Protein ◽  
Wool Growth ◽  
Staple Strength ◽  
Fleece Weight

Although sheep with a relatively high fleece weight have reduced fat deposition and a lower reproductive rate, research has failed to identify any specific metabolic demand that growing a fleece places on the physiology of the sheep. This paper reports two experiments in which the effect of fleece weight was examined in ewes infused intravenously with amino acids. The first experiment was carried out when the ewes were 107 days pregnant, and the second 2 years later in non-pregnant ewes from the same flock. The ewes were derived initially from groups that differed in staple strength, but there was no effect of staple strength group on the characteristics measured in either experiment. In Expt 2, ewes were also infused with a bolus of l-[ring-d5] phenylalanine, and the enrichment in plasma determined by GC/mass spectrometry over the next 24 h. In both experiments, fasting plasma insulin concentrations were lower (P < 0.05) in ewes with a high fleece weight, and this difference continued during infusion in Expt 2 (P < 0.05). In Expt 1, infusion of ewes with amino acids resulted in higher (P < 0.05) plasma concentrations of α-amino nitrogen (indicating amino acids) in the ewes with a higher fleece weight, and in Expt 2, ewes with a high fleece weight had a 19% higher rate of appearance of endogenous phenylalanine (P < 0.05). We conclude that sheep with high wool growth rates have higher whole-body protein turnover rate, which may be achieved in part by lower insulin concentrations. Lower insulin in turn provides a mechanism through which wool growth rate may influence energy availability to other tissues.

scholarly journals In vivo threonine oxidation in growing pigs fed on diets with graded levels of threonine

1996 ◽  
Vol 75 (6) ◽  
pp. 825-837 ◽  
Author(s):  
N. Le Floc'h ◽  
C. Obled ◽  
B. Sève
Keyword(s):  
Specific Radioactivity ◽  
Vena Cava ◽  
Live Weight ◽  
Growing Pigs ◽  
Whole Body ◽  
Constant Infusion ◽  
Balanced Diet ◽  
Liver And Pancreas ◽  
Venous Plasma

Threonine oxidation to glycine was investigated in vivo in twelve growing pigs (27·4 kg live weight) fed on one of the following three diets with graded levels of threonine supply: a low-threonine diet (LT), a control well-balanced diet (C) or a high-threonine diet (HT), during 10h constant infusion of L-[1-13C]threonine and [2-3H]glycine in the cranial vena cava and [l-14C]glycine in the portal vein.13C-threonine and glycine enrichments and [3H]glycine and [14C]glycine specific radioactivities (SR) were determined at plateau in peripheral venous plasma, liver and pancreas. Glycine praduction rates calculated from plasma [2-3H]glycine or [1-14C]glycine SR gave similar values suggesting that [l-14C]glycine SR could be used in order to estimate whole-body glycine flux. The high pancreas [1-13C]glycine enrichment provided evidence that the pancreas may be, with the liver, a major site of threonine oxidation to glycine. Moreover, the present findings suggest that threonine transport into the Liver could be the limiting step of threonine oxidation in this tissue when dietary threonine supply is low. Total threonine oxidation to glycine, calculated from plasma values of enrichment and specific radioactivity, was low and constant when the estimated absorbed threonine was lower than 4 g/d and increased for higher amounts of absorbed threonine.

Animal-intrinsic variation in the partitioning of body protein and lipid in growing pigs

2000 ◽  
Vol 70 (1) ◽  
pp. 29-37 ◽  
Author(s):  
P. W. Knap ◽  
H. Jørgensen
Keyword(s):  
Variance Components ◽  
Growing Pigs ◽  
Whole Body ◽  
Body Lipid ◽  
Genetic Determination ◽  
Body Protein ◽  
Lipid Mass ◽  
Cutaneous Tissue ◽  
Yorkshire Pigs ◽  
Total Body

AbstractBody composition in the pig, and its variation, is mostly referred to in terms of body protein and lipid content of the whole body. This study was made to check for animal-intrinsic variation in the partitioning of body protein into protein pools and of body lipid into lipid depots. Results from serial slaughter trials on 316 Danish Landrace and 76 Danish Yorkshire pigs were used to estimate additive genetic and litter-associated variance components for several traits. These traits were total body protein and lipid mass (TOTPROT and TOTLIPD), the proportions of total body protein that are present in the muscles (PROTMUS) or in the (sub-)cutaneous tissue plus bones (connective tissue protein, PROTCON), and the proportions of total body lipid that are present in the (sub-)cutaneous tissue (LIPDSUB), in the muscles (inter- and intramuscular fat, LIPDMUS), or in the bones (LIPDBON). TOTPROT and TOTLIPD were adjusted by regression for body weight; PROTMUS and PROTCON were adjusted for PROTCON, and LIPDSUB, LIPDMUS and LIPDBON were adjusted for TOTLIPD. The pooled estimates (± s.e.) of the degree of genetic determination (the sum of the additive genetic and litter-associated variance components, which approximates the repeatability) of these traits were 0·48 ± 0·19 for TOTPROT, 0·56 ± 0·20 for TOTLIPD, 0·56 ± 0·12 for PROTMUS, 0·57 ± 0·15 for PROTCON, 0·32 ± 0·10 for LIPDMUS, 0·33 ± 0·12 for LIPDSUB, and 0·22 ± 0·10 for LIPDBON. It is concluded that there is animal-intrinsic variation in partitioning of body protein and lipid.

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