Incorporating turn-over in whole body protein retention ef.ciency in pigs

2005 ◽  
Vol 80 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Z. Roux
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Hormonal Control ◽  
Whole Body ◽  
Insulin Like Growth Factor ◽  
Retention Efficiency ◽  
Body Protein ◽  
Protein Retention ◽  
Limit Value ◽  
Turn Over

The magnitude of the discrepancy between conventional regression estimates of protein retention efficiency and theoretical estimates of synthesis efficiency indicates a major contribution ascribable to protein turn-over in the generally accepted estimates. As protein turn-over is known to be influenced by diet, feeding level and degree of maturity, this suggests the development of an estimator of protein efficiency that can be adapted for such differences. Therefore, based on generally accepted formulas for growth description, a method of estimating protein retention efficiency was developed which is flexible enough to accommodate different diets, feeding levels and degrees of maturity. Moreover, a formula was derived to convert one type of estimate to the other by regarding constant efficiency as equivalent to variable efficiency at the mid point of the estimation interval. Increase in scientific depth to this descriptive approach is provided by a theoretical consideration of a possible mechanism of hormonal control of protein synthesis and breakdown, ultimately expressed as proportionalities to powers of whole body protein (P). Molecular considerations on cellular synthesis and breakdown indicate a difference between breakdown and synthesis powers equal to (2/9)Q. The factor (2/9) is indicated by an argument based on insulinlike growth factor derived activator diffusion attributes by nucleus and body tissue geometries, whileQis equal to the proportion of nuclei activated by insulin-like growth factor. This proportion is likely to be a function of the concentration of growth factor in the blood. Hence, a linear relationship between intake and blood insulin-like growth factor concentration suggests thatQcan be represented by a scaled transformation of intake, 0 ≤Q≤ 1, such that a value ofQ= 1 represents ad libitum intake on a suitable diet andQ= 0 intake at the maintenance requirement. The quantification of breakdown and synthesis power differences by (2/9)Qleads to kP= {1 + [1 − (P/α)(2/9)Q]−1/6}−1, for turn-over related protein retention efficiency (kP), with α the limit value of P at maturity, so that 0 ≤ (P/α) ≤ 1. Experimental estimates, derived from direct estimates of whole body protein synthesis and breakdown at predetermined levels of intake, are in excellent agreement with the theoretical (2/9)Qin the power associated with (P/α) in kP. Furthermore, conventional multiple regression retention efficiencies satisfactorily approximate the turn-over related retention efficiency that can be calculated at a given level of intake for the mid point of the interval covered by the regression estimates.

Incorporating turn-over in whole body protein retention efficiency in cattle and sheep

2005 ◽  
Vol 80 (3) ◽  
pp. 345-351 ◽  
Author(s):  
C. Z. Roux
Keyword(s):  
Multiple Regression ◽  
General Rule ◽  
The Body ◽  
Whole Body ◽  
Regression Estimate ◽  
Retention Efficiency ◽  
Body Protein ◽  
Protein Retention ◽  
Limit Value ◽  
Turn Over

AbstractIn pigs the quantification of breakdown and synthesis by powers of body protein led to the estimation of turn-over related protein retention efficiency by the equation kP= {1 + [1 − (P/α)(2/9)Q]−1/6}−1, with α the limit value of whole body protein (P) maturity, so that 0 ≤(P/α)≤1. The factor 2/9 is derived from diffusion attributes indicated by cell and nucleus geometries α and Q represents a scaled transformation of intake, 0 ≤ Q ≤ 1, such that a value of Q = 1 may represent ad libitum intake and Q = 0 the intake at the maintenance requirement. Published observations on finishing steers provide estimates of whole body protein synthesis and breakdown at pre-determined levels of intake in confirmation of the theoretical (2/9)Q power associated with (P/α) inkP. Further confirmation of the (2/9)Q power in cattle follows from satisfactory agreement between an estimate of conventional multiple regression retention efficiency and the turn-over related retention efficiency calculated at the given level of intake, for the mid point of the body mass interval covered by the regression estimate. In addition, a simulation experiment on cattle from the literature gives power estimates of protein breakdown and synthesis in general agreement with those accepted for pigs. Examples on both fine and coarse diets are employed to suggest a general rule for prediction on diets causing submaximal efficiency due to suboptimal intakes.In sheep, evidence derived from estimates of conventional multiple regression efficiencies suggests that the rule (a-b) = (2/9) Q for the calculation ofkPshould be reserved for the description of compensatory growth. Protein retention efficiency for ordinary growth should be described by an adaptation of the rule derived for suboptimal intakes.

scholarly journals Incorporating turnover in estimates of protein retention efficiency for different body tissues

2006 ◽  
Vol 95 (2) ◽  
pp. 246-254 ◽  
Author(s):  
C. Z. Roux
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Whole Body ◽  
Muscle Fibres ◽  
Retention Efficiency ◽  
Tissue Protein ◽  
Protein Retention ◽  
Body Tissues ◽  
Breakdown Rates ◽  
The Relationship

Formulated in terms of protein synthesis (PS) and protein retention (PR), a definition of turnover-related protein retention efficiency (kP) allows the expression kP=[1+(PS/PR)/6]−1, 6 representing the ratio of the energy equivalent of protein to the cost of synthesis. By combining plausible hormonal and cellular control mechanisms of protein (P) growth, it is possible to derive (PS/PR)=[Q{(P/α)−(4/9)Y−1}]−1+1, allowing the calculation of kPby substitution. The symbol α represents the limit value of protein growth, while the term 4/9 derives from the power in the relationship between the concentration of growth factor-related activator in the nucleus and cell volume (cv). Y is the power in the relationship between cv and total tissue protein, and Q represents the proportion of growth factor-activated nuclei in a tissue. The proportion Q can be estimated from simple functions of intake rates or blood growth factor concentrations. Estimates of Y are derived from histological considerations or calculated from experimental observations; Y=1 for multinucleated skeletal muscle fibres and Y=1/3, 1/2, 1/6 on average for mononucleated cell tissues, skin or bone and viscera, respectively. To apply kPto the whole body, an average value of Y=1/2 can be taken. Experimental observations on tissue protein synthesis and breakdown rates yield direct estimates of kPin satisfactory agreement with comparable theoretical predictions.

scholarly journals Insulin-like Growth Factor I (IGF-I) Increases Whole Body Protein Synthesis in Contrast to Insulin Which Reduces Proteolysis

1994 ◽  
Vol 3 (Supple5) ◽  
pp. 240-240
Author(s):  
David L. Russell-Jones ◽  
Marlot A. Umpleby ◽  
Tom D. Hennessy ◽  
Peter H. Sonksen
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Whole Body ◽  
Insulin Like Growth Factor ◽  
Body Protein ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

scholarly journals Correlation between the urinary excretion of acid-soluble peptides, fractional synthesis rate of whole body proteins, and plasma immunoreactive insulin-like growth factor-l/somatomedin C concentration in the rat

1990 ◽  
Vol 63 (3) ◽  
pp. 515-520 ◽  
Author(s):  
Taek Jeong Nam ◽  
Tadashi Noguchi ◽  
Ryuhei Funabiki ◽  
Hisanori Kato ◽  
Yutaka Miura ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Urinary Excretion ◽  
Whole Body ◽  
Synthesis Rate ◽  
Immunoreactive Insulin ◽  
Insulin Like Growth Factor ◽  
Body Protein ◽  
Somatomedin C ◽  
Plasma Immunoreactive Insulin

The relations between the urinary excretion of acid-soluble peptide (ASP)-form amino acids, the rate of whole body protein synthesis and plasma immunoreactive insulin-like growth factor-1/somatomedin C concentration were investigated in rats. The urinary ASP-form leucine plus valine excretion correlated well with the rate of whole body protein synthesis and with the plasma immunoreactive insulin-like growth factor-1 concentration. The results provide further evidence for the hypothesis that urinary excretion of ASP is an excellent index of the status of protein metabolism in animals.

Level of cottonseed meal but not frequency of feeding regulates whole-body protein synthesis and growth of sheep fed a roughage diet

2009 ◽  
Vol 49 (11) ◽  
pp. 1023
Author(s):  
L. P. Kahn ◽  
Somu B. N. Rao ◽  
J. V. Nolan
Keyword(s):  
Growth Rate ◽  
Protein Synthesis ◽  
Cottonseed Meal ◽  
Whole Body ◽  
Body Protein ◽  
Protein Supplements ◽  
Protein Retention ◽  
Medium Quality ◽  
Protein Rich

An incomplete factorial experiment was conducted to determine the effect of level and frequency of feeding of a protein-rich supplement on the growth and whole-body protein metabolism of young sheep fed a medium quality roughage diet. Cottonseed meal (CSM) was used as the protein supplement and provided at 0, 0.2 or 0.4% liveweight per day at a frequency of 1 or 3 times each week and chopped oaten (0.95) and lucerne (0.05) hay was the roughage. Growth rate more than doubled (P < 0.01) following provision of CSM but there was no advantage of feeding CSM at the highest level. Frequency of feeding CSM did not alter growth rate. Intake of hay was little affected by CSM and as a consequence the food conversion ratio declined (P < 0.01) favourably from 22 : 1 (nil CSM) to 9 : 1 as a result of supplementation. The rate of whole-body protein synthesis increased (P < 0.01) in response to the highest level of CSM with no apparent change in protein degradation, underpinning an increase (P < 0.01) in protein retention. These results highlight the role of protein supplements for promoting growth of young sheep on roughage diets and indicate that these supplements need to be provided only once a week.

A note on the effect of ageing on whole-body protein turn-over in goats

1988 ◽  
Vol 46 (3) ◽  
pp. 479-481 ◽  
Author(s):  
T. Muramatsu ◽  
Y. Ueda ◽  
T. Hirata ◽  
J. Okumura ◽  
I. Tasaki
Keyword(s):  
Body Weight ◽  
Protein Synthesis ◽  
Mammalian Species ◽  
Weight Basis ◽  
Dynamic State ◽  
Whole Body ◽  
Body Protein ◽  
Turn Over

In ruminants a dynamic state of protein turn-over has been poorly understood although the methodology of measuring the rate of protein turn-over has recently been advanced to a great extent (Waterlow, Garlick and Millward, 1978). Available evidence suggests that ruminants such as sheep and cows are no exception among various mammalian species when whole-body protein synthesis of adult animals is compared on a metabolic body-weight basis (Waterlow et al., 1978; Reeds and Lobley, 1980).

scholarly journals Skeletal and cardiac myopathy in HIV-1 transgenic rats

2008 ◽  
Vol 295 (4) ◽  
pp. E964-E973 ◽  
Author(s):  
Anne M. Pruznak ◽  
Ly Hong-Brown ◽  
Rachel Lantry ◽  
Pengxiang She ◽  
Robert A. Frost ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Growth Factor ◽  
Muscle Atrophy ◽  
Cardiac Mass ◽  
Whole Body ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Growth Factor I ◽  
Hiv 1

The mechanism by which human immunodeficiency virus (HIV)-1 infection in humans leads to the erosion of lean body mass is poorly defined. Therefore, the purpose of the present study was to determine whether transgenic (Tg) rats that constitutively overexpress HIV-1 viral proteins exhibit muscle wasting and to elucidate putative mechanisms. Over 7 mo, Tg rats gained less body weight than pair-fed controls exclusively as a result of a proportional reduction in lean, not fat, mass. Fast- and slow-twitch muscle atrophy in Tg rats did not result from a reduction in the in vivo-determined rate of protein synthesis. In contrast, urinary excretion of 3-methylhistidine, as well as the content of atrogin-1 and the 14-kDa actin fragment, was elevated in gastrocnemius of Tg rats, suggesting increased muscle proteolysis. Similarly, Tg rats had reduced cardiac mass, which was independent of a change in protein synthesis. This decreased cardiac mass was associated with a reduction in stroke volume, but cardiac output was maintained by a compensatory increase in heart rate. The HIV-induced muscle atrophy was associated with increased whole body energy expenditure, which was not due to an elevated body temperature or secondary bacterial infection. Furthermore, the atrophic response could not be attributed to the development of insulin resistance, decreased levels of circulating amino acids, or increased tissue cytokines. However, skeletal muscle and, to a lesser extent, circulating insulin-like growth factor I was reduced in Tg rats. Although hepatic injury was implicated by increased plasma levels of aspartate and alanine aminotransferases, hepatic protein synthesis was not different between control and Tg rats. Hence, HIV-1 Tg rats develop atrophy of cardiac and skeletal muscle, the latter of which results primarily from an increased protein degradation and may be related to the marked reduction in muscle insulin-like growth factor I.

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