Rat muscle structure and metabolism in relation to age and food intake

1982 ◽  
Vol 242 (1) ◽  
pp. R89-R93 ◽  
Author(s):  
R. J. McCarter ◽  
E. J. Masoro ◽  
B. P. Yu
Keyword(s):  
Oxygen Consumption ◽  
Muscle Mass ◽  
Food Restriction ◽  
Fiber Diameter ◽  
Male Rats ◽  
Progressive Loss ◽  
Age Related ◽  
Group A ◽  
Ad Libitum ◽  
Ad Libitum Intake

Age changes in oxygen consumption and the structural composition of the lateral omohyoideus muscle were studied in adult male rats. The rate were either fed ad libitum (group A) or 60% of the ad libitum intake (group R). An age-related loss in muscle mass did not occur even at advanced ages in group A or group R rats. Muscle fiber diameter decreased with age in both groups but a concomitant increase in the number of fibers prevented a change in muscle mass. The muscles of group R rats contained the same number of fibers as those of group A rats at all ages. The muscles of group A rats showed a progressive loss in rate of resting oxygen consumption until 18 mo of age. A similar but less marked loss in oxygen consumption occurred in the muscles of group R rats. These results provide further evidence that life-prolonging food restriction modulates physiological changes associated with the aging process.

Energy metabolism and aging: a lifelong study of Fischer 344 rats

1992 ◽  
Vol 263 (3) ◽  
pp. E448-E452 ◽  
Author(s):  
R. J. McCarter ◽  
J. Palmer
Keyword(s):  
Energy Metabolism ◽  
Metabolic Rate ◽  
Food Restriction ◽  
Fischer 344 Rats ◽  
Fuel Utilization ◽  
Fischer 344 ◽  
Group A ◽  
Ad Libitum ◽  
Group B ◽  
Ad Libitum Intake

Metabolic rate is widely regarded as an important component of aging processes, but variation of metabolic rate with age has not been well characterized. The purpose of the present study was to measure daily metabolic rate under usual living conditions over the lifespan of barrier-maintained Fischer 344 rats. In addition, effects of life-prolonging food restriction were assessed. Metabolic rate was measured indirectly by analysis of gas entering and leaving standard rodent cages over a 24-h period. Group A rats were fed ad libitum. Group B rats were fed 60% of ad libitum intake from 6 wk of age. Both group A and group B rats exhibited variation of metabolic rate per unit lean mass over the lifespan, with metabolic rate decreasing from 6 to 18 mo and then increasing from 18 to 24 mo of age. Results show estimates of lifetime energy expenditure in rats should take account of variability of metabolic rate and confirm the life-prolonging action of food restriction is not a consequence of reduced metabolic rate per unit metabolic mass. Rather, restricted rats are able to sustain appropriate fluxes of nutrients and appropriate metabolic rate under conditions of fuel utilization which promote maintenance of cellular homeostasis.

Food restriction as a modulator of age-related changes in serum lipids

1980 ◽  
Vol 238 (3) ◽  
pp. E253-E257 ◽  
Author(s):  
G. U. Liepa ◽  
E. J. Masoro ◽  
H. A. Bertrand ◽  
B. P. Yu
Keyword(s):  
Serum Cholesterol ◽  
Food Restriction ◽  
Serum Triglyceride ◽  
Serum Levels ◽  
Male Rats ◽  
Serum Free Fatty Acid ◽  
Young Rats ◽  
Age Related ◽  
Ad Libitum ◽  
Age Related Changes

Fischer 344 male rats were either fed ad libitum or 60% of the ad libitum intake. The restriction of food intake markedly increased the median length of life. Postabsorptive serum cholesterol and phospholipid concentrations increase in the ad libitum-fed rats with increasing age. Life-prolonging food restriction does not influence the serum levels of these lipids in young rats but delays the age-related increase in concentrations. Postabsorptive serum free fatty acid (FFA) concentrations decrease with advancing age in ad libitum-fed rats. Life-prolonging food restriction, while not affecting the serum FFA levels in young rats, delays and possibly partially prevents the age-related decrease in concentration. Food restriction lowers postabsorptive serum triglyceride levels at all ages studied. The data on serum cholesterol, phospholipids, and FFA provide further evidence that food restriction delays age-related changes in the physiological systems of rats. This delay of physiological decline may well retard the occurrence of age-related disease processes, thus prolonging life.

Life-Span Study of SPF Fischer 344 Male Rats Fed Ad Libitum or Restricted Diets: Longevity, Growth, Lean Body Mass and Disease

2002 ◽  
Vol 2002 (37) ◽  
Author(s):  
Byung Pal Yu ◽  
Edward J. Masoro ◽  
Ikuo Murata ◽  
Helen A. Bertrand ◽  
Frederick T. Lynd
Keyword(s):  
Life Span ◽  
Lean Body Mass ◽  
Body Mass ◽  
Food Restriction ◽  
Male Rats ◽  
Life Span Study ◽  
Renal Lesions ◽  
Fischer 344 ◽  
Group A ◽  
Ad Libitum

A life-span study was carried out on longevity, pathologic lesions, growth, lean body mass, and selected aspects of muscle of barrier-maintained SPF Fischer 344 rats fed either ad libitum (Group A) or 60% of the ad libitum intake (Group R). Food restriction was as effective in prolonging the life of already long-lived SPF rats as previously shown for rats maintained in conventional facilities. Food restriction not only increased the mean length of life but also acted to extend life-span since more than 60% of the Group R rats lived longer than the longest lived Group A rat. Renal lesions occurred at an earlier age in Group A rats than in Group R rats and progressed more rapidly. Death of most Group A rats was associated with severe renal lesions while few Group R rats showed such lesions at death. Food restriction was also found to delay or prevent interstitial cell tumors of the testes, bile duct hyperplasia, myocardial fibrosis and myocardial degeneration. Gastrocnemius muscle mass declined in advanced age and food restriction delayed this decline. Interestingly, however, lean body mass did not progressively decline with increasing age but rather decline occurred only after the onset of the terminal disease process. Copyright (c) The Gerontological Society of America. Reproduced by permission of the publisher. Byung Pal Yu, Edward J. Masoro, Ikuo Murata, Helen A. Bertrand, Frederick T. Lynd, Life Span Study of SPF Fischer 344 Male Rats Fed Ad Libitum or Restricted Diets: Longevity, Growth, Lean Body Mass and Disease. J. Gerontol. 37 , 130-141 (1982).

Age-related susceptibility to muscle damage following mechanotherapy in rats recovering from disuse atrophy

2021 ◽  
Author(s):  
Zachary R Hettinger ◽  
Kyoko Hamagata ◽  
Amy L Confides ◽  
Marcus M Lawrence ◽  
Benjamin F Miller ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Mass ◽  
Older Adult ◽  
Recovery Period ◽  
Male Rats ◽  
Hindlimb Suspension ◽  
Disuse Atrophy ◽  
Adult Rats ◽  
Transverse Stiffness ◽  
Age Related

Abstract The inability to fully recover lost muscle mass following periods of disuse atrophy predisposes older adults to lost independence and poor quality of life. We have previously shown that mechanotherapy at a moderate load (4.5 N) enhances muscle mass recovery following atrophy in adult, but not older adult rats. We propose that elevated transverse stiffness in aged muscle inhibits the growth response to mechanotherapy and hypothesize that a higher load (7.6 N) will overcome this resistance to mechanical stimuli. F344/BN adult and older adult male rats underwent 14-days of hindlimb suspension, followed by 7-days of recovery with (RE+M) or without (RE) mechanotherapy at 7.6 N on gastrocnemius muscle. The 7.6 N load was determined by measuring transverse passive stiffness and linearly scaling up from 4.5 N. No differences in protein turnover or mean fiber cross sectional area were observed between RE and RE+M for older adult rats or adult rats at 7.6 N. However, there was a higher number of small muscle fibers present in older adult, but not adult rats, which was explained by a 16-fold increase in the frequency of small fibers expressing embryonic myosin heavy chain. Elevated central nucleation, satellite cell abundance, and dystrophin -/laminin + fibers were present in older adult rats only following 7.6 N, while 4.5 N did not induce damage at either age. We conclude that age is an important variable when considering load used during mechanotherapy and age-related transverse stiffness may predispose older adults to damage during the recovery period following disuse atrophy.

FOOD CONSUMPTION AND RECTAL TEMPERATURE IN RATS DURING THIAMINE DEFICIENCY AND REPLETION

1963 ◽  
Vol 41 (12) ◽  
pp. 2463-2471 ◽  
Author(s):  
M. J. Veen ◽  
G. Russell ◽  
G. H. Beaton
Keyword(s):  
Food Consumption ◽  
Rectal Temperature ◽  
Food Restriction ◽  
Control Diet ◽  
Significant Rise ◽  
Male Rats ◽  
Thiamine Hydrochloride ◽  
Deficient Diet ◽  
Ad Libitum ◽  
Deficient Group

Rectal temperature in male rats fell slowly and gradually from ad libitum and pair-led control levels throughout a thiamine depletion period. During this period, food consumption dropped suddenly and sharply to a minimal level. A single oral dose of 50 μg of thiamine hydrochloride produced, within 4 hours, a significant rise (to less than control levels) in rectal temperature and an increase in food consumption within 24 hours. The increase in temperature was independent of the ingestion of food since diet was withheld during the 4 hours following thiamine administration. Subsequent feeding of control diet (containing thiamine) had not further increased the "4-hour" temperature after 24 hours. With continued feeding of control diet, rectal temperature rose to control levels after 3 days. On subsequent withdrawal of dietary thiamine from the deficient group, temperature and food consumption fell as before. When the animals were again repleted with 50 μg thiamine and deficient diet was continued, temperatures rose to the same level reached after the first thiamine administration. A third deprivation and repletion produced identical results.Food restriction alone, in pair-fed control groups, induced an initial elevation of rectal temperature above ad libitum control levels as temperatures in the deficient group were falling, and an eventual decrease below ad libitum control levels only after prolonged food restriction. It is suggested that the initial fall in body temperature in thiamine-deficient rats is not simply a terminal result of food restriction per se, but may reflect alterations in metabolism due to the deficiency.

Food restriction prevents age-related polyuria by vasopressin-dependent recruitment of aquaporin-2

2001 ◽  
Vol 281 (6) ◽  
pp. F1123-F1131 ◽  
Author(s):  
S. Combet ◽  
L. Teillet ◽  
G. Geelen ◽  
B. Pitrat ◽  
R. Gobin ◽  
...  
Keyword(s):  
Food Restriction ◽  
Marked Decrease ◽  
Collecting Duct ◽  
Apical Region ◽  
Principal Cells ◽  
Aquaporin 2 ◽  
Age Related ◽  
Old Rats ◽  
Ad Libitum ◽  
Chronic Food Restriction

First published August 8, 2001; 10.1152/ajprenal.00139.2001.—The mechanisms underlying the prevention of age-related polyuria by chronic food restriction were investigated in female WAG/Rij rats. The decreased osmolality of renal papilla observed in senescent rats was not corrected by food restriction. A reduced urea content in the inner medulla of senescent rats, fed ad libitum or food-restricted, was suggested by the marked decrease in expression of UT-A1 and UT-B1 urea transporters. Aquaporin-2 (AQP2) downregulation in the inner medulla of senescent rats was partially prevented by food restriction. Both AQP2 and the phosphorylated form of AQP2 (p-AQP2), the presence of which was diffuse within the cytoplasm of collecting duct principal cells in normally fed senescent rats, were preferentially targeted at the apical region of the cells in food-restricted senescent animals. Plasma vasopressin (AVP) was similar in 10- and 30-mo-old rats fed ad libitum, but was doubled in food-restricted 30-mo-old rats. This study indicates that 1) kidney aging is associated with a marked decrease in AQP2, UT-A1, and UT-B1 expression in the inner medulla and a reduced papillary osmolality; and 2) the prevention of age-related polyuria by chronic food restriction occurs through an improved recruitment of AQP2 and p-AQP2 to the apical membrane in inner medulla principal cells, permitted by increased plasma AVP concentration.

Circulating hyaluronan levels in the rodent: effects of age and diet

1995 ◽  
Vol 268 (4) ◽  
pp. C952-C957 ◽  
Author(s):  
J. Yannariello-Brown ◽  
S. H. Chapman ◽  
W. F. Ward ◽  
T. C. Pappas ◽  
P. H. Weigel
Keyword(s):  
Fish Meal ◽  
Caloric Intake ◽  
Protein Source ◽  
Male Rats ◽  
Semisynthetic Diet ◽  
Fischer 344 ◽  
Age Related ◽  
Old Rats ◽  
Ad Libitum ◽  
Age Related Changes

Circulating hyaluronan (HA) levels were investigated as a function of age and diet in Fischer 344 male rats. A biphasic pattern of age-related changes was observed in rats fed ad libitum a diet in which the protein source was soya/fish meal. HA levels in 3- to 6- and 22- to 29-mo-old rats were not statistically different. However, HA levels in 12- to 20-mo-old rats were 10-29% of the levels in younger or aged adults. HA levels were also measured in rats fed ad libitum a semisynthetic diet in which the protein source was hydrolyzed casein. Whereas the two colonies exhibited similar biphasic age-related changes, HA levels differed 4- to 20-fold at every age examined. Caloric restriction affected HA levels in 19-mo-old casein-fed rats; HA levels were 2.3 times higher than age-matched controls and were not statistically different from young or aged animals. Serum and plasma HA levels were identical in the same individuals at all ages tested. These data suggest that HA turnover and metabolism in the rat are affected by age, dietary composition, and caloric intake.

Diminished overload-induced hypertrophy in aged fast-twitch skeletal muscle is associated with AMPK hyperphosphorylation

2005 ◽  
Vol 98 (2) ◽  
pp. 557-564 ◽  
Author(s):  
David M. Thomson ◽  
Scott E. Gordon
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Male Rats ◽  
Brown Norway ◽  
Ampk Phosphorylation ◽  
Age Related ◽  
Ampk Activity ◽  
Slow Twitch ◽  
Fast Twitch

Skeletal muscle mass declines with age, as does the potential for overload-induced fast-twitch skeletal muscle hypertrophy. Because 5′-AMP-activated protein kinase (AMPK) activity is thought to inhibit skeletal muscle protein synthesis and may therefore modulate muscle mass and hypertrophy, the purpose of this investigation was to examine AMPK phosphorylation status (a marker of AMPK activity) and its potential association with the attenuated overload-induced hypertrophy observed in aged skeletal muscle. One-week overload of fast-twitch plantaris and slow-twitch soleus muscles was achieved in young adult (8 mo; n = 7) and old (30 mo; n = 7) Fischer344 × Brown Norway male rats via unilateral gastrocnemius ablation. Significant ( P ≤ 0.05) age-related atrophy (as measured by total protein content) was noted in plantaris and soleus control (sham-operated) muscles. In fast-twitch plantaris muscles, percent hypertrophy with overload was significantly attenuated with age, whereas AMPK phosphorylation status as determined by Western blotting [phospho-AMPK (Thr172)/total AMPK] was significantly elevated with age (regardless of loading status). There was also a main effect of loading on AMPK phosphorylation status in plantaris muscles (overload > control). Moreover, a strong and significant negative correlation ( r = −0.82) was observed between AMPK phosphorylation status and percent hypertrophy in the overloaded plantaris muscles of all animals. In contrast to the plantaris, overload-induced hypertrophy of the slow-twitch soleus muscle was similar between ages, and AMPK phosphorylation in this muscle was also unaffected by age or overload. These data support the possibility that an age-related elevation in AMPK phosphorylation may partly contribute to the attenuated hypertrophic response observed with age in overloaded fast-twitch plantaris muscle.

scholarly journals Use of ractopamine during compensatory gain of finishing pigs on carcass and meat performance and quality

2017 ◽  
Vol 69 (6) ◽  
pp. 1660-1668 ◽  
Author(s):  
E.M.J. Barbosa ◽  
A.M. Bridi ◽  
A.K. Novais ◽  
R.K.S. Santos ◽  
G. Frederico ◽  
...  
Keyword(s):  
Weight Gain ◽  
Food Restriction ◽  
Fiber Diameter ◽  
Live Weight ◽  
Feed Restriction ◽  
Finishing Pigs ◽  
Feed Conversion ◽  
Ethereal Extract ◽  
Ad Libitum ◽  
Compensatory Gain

ABSTRACT The objective of this study was to evaluate the effects of compensatory gain associated with the use of 10ppm ractopamine after a period of feed restriction in finishing pigs on performance, carcass and meat quality. Twenty castrated males and 20 females, at 110 days of age and 66.137±6.13kg live weight, were submitted to four treatments using a 2 x 2 factorial design (fed ad libitum or with 20% restriction between 0(21 days of age and fed with or without 10ppm ractopamine for 22(42 days of experimentation), with 10 replicates (animals). There was no interaction between the factors for any of the evaluated parameters. Animals treated with ractopamine presented better weight gain (1.083 versus 1.259kg), feed conversion (2.910 versus 2.577), warm and cold carcass weight (86.08 versus 89.00 and 83.46 versus 87.20kg, respectively), loin depth (63.02 versus 68.40mm), loin eye area (41.43 versus 46.59mm2) and muscle fiber diameter (27.48 versus 35.85μm). Animals submitted to feed restriction followed by ad libitum feed presented compensatory gain without losses to carcass and meat characteristics, but with a reduction in the ethereal extract (2.19 versus 1.64%) and lower water loss due to thawing in the meat (11.35 versus 9.42%). The effects of compensatory gain after food restriction and ractopamine are independent of the parameters evaluated.

A note on the combined effects of exercise and food restriction on plasma enzyme activities in the rat

1969 ◽  
Vol 47 (4) ◽  
pp. 396-398 ◽  
Author(s):  
J. R. Beaton ◽  
B. Oyster
Keyword(s):  
Food Restriction ◽  
Acute Exercise ◽  
Male Rats ◽  
Elevated Plasma ◽  
Malic Dehydrogenase ◽  
Individual Effects ◽  
Ad Libitum ◽  
The Individual ◽  
Exercise And Training ◽  
And Training

Plasma activities of malic dehydrogenase (MDH) and glutamic–pyruvic transaminase (GPT) were measured in adult male rats made to swim for 1 h either as a single, acute exercise or in repeated exercises (training) in the presence of a 50% food restriction. Food restriction per se elevated MDH and lowered GPT activities. Food-restricted rats responded to both acute exercise and training by an elevated plasma MDH activity. The effect of exercise on plasma MDH activity in these animals was greater than in rats fed ad libitum and was greater than could be accounted for by the summation of the individual effects of training and of food restriction. Plasma GPT activity was not altered by exercise in rats fed ad libitum or in food-restricted animals. It would appear, as suggested previously, that plasma MDH activity may be a useful biochemical criterion of training.

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