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PubMedDate not supplied

Medical reports recommending work restrictions at a teaching hospital in Brazil.

This non-experimental and cross-sectional descriptive study aimed to evaluate medical reports recommending work restrictions for workers at a teaching hospital in Brazil. A form was used for data collection, characterizing the medical reports and work restrictions, with its content previously validated. A total of 176 medical reports was analyzed, containing 337 work restrictions, recommended from January 2001 to January 2004. The results demonstrated a high rate of work restrictions in the study hospital. The most restrictions frequent were ergonomic (78.6%), and the most often prescribed were: no weight lifting or carrying and no repetitive movements. There was an average of two restrictions per medical report, 79.5% of which were definitive and the mean restriction period was 13 months.

Brazil↗

PubMed1999

Study of the evolution of the placenta and fetal pancreas in the pathophysiology of growth retardation intrauterine due to restricted maternal diet.

CONTEXT: Intrauterine growth retard (IUGR) continues to be a significant perinatology problem at the end of this century. The nature of the etiologic agent, the time when the attack occurred during pregnancy and its duration affect the type of IUGR. OBJECTIVE: To study the evolution of fetal pancreas and placenta between the 18th and 21st day of pregnancy in rats submitted to maternal protein-calorie restriction. DESIGN: Randomized controlled trial on laboratory animal. SAMPLE: Forty-one normoglycemic pregnant Wistar rats. INTERVENTION: Rats were divided into six experimental groups according to their access to food and date of cesarean section (18th or 21st day): control with free access to food; diet restricted to 25% introduced on 1st day of pregnancy; and diet restricted to 25% after the 3rd day of pregnancy. MAIN MEASUREMENTS: Newborn weight, placenta weight, histopathological study (morphological histochemistry). RESULTS: Maternal protein-calorie malnutrition caused intrauterine growth retard (IUGR) after the 18th day of pregnancy. Dietary restriction did not interfere with the morphology of the fetal pancreas and the immunohistochemical study of the placenta showed that glycogen stores were decreased between the 18th and 21st day in the control group and in a diet restricted to 25% from the first day of pregnancy. Dietary restriction after the 3rd day of pregnancy led to low placental glycogen concentrations on the 18th day and disappearance on the 21st day. CONCLUSION: The pathophysiology of IUGR due to maternal protein-calorie restriction in rats is related to lower placental weight and low placental glycogen stores.

Animals↗

PubMed1976

Recovery of pituitary secretion of gonadotrophins and prolactin during re-feeding after chronic restricted feeding in female rats.

The effects on reproductive function of restriction to one half Of the normal food intake for 30 or 60 days and subsequent unrestricted feeding were investigated in adult female Sprague-Dawley rats. Restricted feeding resulted in the cessation of oestrous cycles within 9 to 28 days, associated with decreased pituitary, ovarian and uterine weights. Pituitary content and concentration of FSH were increased by restricted feeding and the levels of FSH in 60 day underfed rats were about twice as high as those of the controls at dioestrus. There was little difference in pituitary LH content between the underfed groups and the controls at the end of restricted feeding. Pituitary LH concentration was significantly higher in rats underfed for 60 days than in the control rats. Pituitary prolactin content was one half and one third of that in control rats in rats underfed for 30 and 60 days respectively. Pituitary prolactin concentration was also decreased by restricted feeding. At the end of restricted feeding, no differences in serum LH and prolactin levels were found between the groups, whereas the serum FSH level in 60 day underfed rats was higher than that in the controls at dioestrus. After re-feeding, normal oestrous cycles returned within 3-5 days in almost all rats, regardless of the length of the previous cessation of oestrous cycles. Ptuitary contents of FSH and LH in underfed rats decreased after re-feeding following the return of oestrous cycles. The rate of decrease was much greater in 60 day underfed rats than that in 30 day underfed rats. On the other hand, serum levels of FSH, LH and prolactin in these underfed rats were increased by re-feeding and the levels in the evening of the first pro-oestrus were higher than those in the morning of dioestrus and pro-oestrus. Serum levels of these hormones increased more in 60 day underfed rats than in the other groups at any stage. After re-feeding, pituitary, ovarian and uterine weights increased and the uterine epithelial layer was clearly repaired in both underfed groups, although not always to the control levels by the first oestrus. The end-bud system of the mammary gland which degenerated during restricted feeding was comparable to that of the controls at the first oestrus after re-feeding in 30 day underfed rats, but not in 60 day underfed rats.

Animals↗

PubMed1997

Moderate food restriction reduces serum IGF-I and alters circulating IGF-binding protein profiles in lactating rats.

The role of somatogenic and lactogenic hormones in the adaptative mechanisms which occur in response to nutrient restriction during lactation is unknown. To characterize the effect of food restriction during lactation on serum IGF-I, GH and prolactin concentrations and serum IGF-binding protein (IGFBP) profiles, lactating dams had free access to food (control) or were restricted to 60% of control intake during pregnancy and lactation (RPL) or only during lactation (RL). Serum, milk and mammary gland samples were collected throughout lactation. RL dams lost body weight, control dams gained weight, while RPL dams maintained body weight during lactation. By day 20, body and mammary gland weights of RL and RPL dams did not differ and were lower than control (P < 0.05). Serum IGF-I concentrations in restricted groups were lower than control (P < 0.05), however, hepatic expression of IGF-I mRNA did not differ between groups in early (day 1) or mid-lactation (day 8) and was increased on day 20 in RL dams compared with RPL or control. These data suggest that serum IGF-I and hepatic IGF-I mRNA expression are not co-ordinately regulated in the food-restricted lactating rat. In early lactation, serum IGFBP-3 was lower in RPL dams than control (P < 0.05), whereas IGFBP-1 and -2 were increased in RL and RPL dams in late lactation compared with control. The decrease in IGFBP-3 and increase in lower molecular weight IGFBP may have contributed to the reduction in serum IGF-I by increasing IGF-I clearance from the circulation. Serum GH and prolactin were measured in samples obtained between 0900 and 1200 h. Serum GH did not differ with the exception of an increase on day 1 in control relative to RPL dams and on day 20 in RL dams relative to RPL and control. Serum prolactin was higher in the RL dams than controls on day 4. In summary, food restriction during pregnancy and lactation or solely during lactation results in similar reductions in serum IGF-I and alterations in serum IGFBP despite differences in body weight responses to food restriction during lactation.

Animals↗

PubMed1999

Hypothalamic-pituitary-adrenal activity and pro-opiomelanocortin mRNA levels in the hypothalamus and pituitary of the rat are differentially modulated by acute intermittent morphine with or without water restriction stress.

Acute administration of morphine stimulates the secretion of hypothalamic-pituitary-adrenal (HPA) hormones, ACTH, beta-endorphin and corticosterone in the rat. In this study we investigated the effects of repeated multiple-dose morphine on HPA activity under two different conditions: without or with water restriction stress. Rats received six intermittent injections of morphine (6.25 mg/kg per injection, s.c.) every 2 h and were killed 30 min after the last injection. The results were as follows. (1) Morphine significantly elevated plasma ACTH and corticosterone levels; water restriction also significantly increased ACTH secretion, but with no significant increase of plasma corticosterone levels. In contrast, rats treated with morphine under the water restriction condition failed to show any increases of either ACTH or corticosterone levels. (2) Morphine did not change pro-opiomelanocortin (POMC) mRNA levels in the anterior pituitary; whereas water restriction significantly increased the POMC mRNA levels. The water restriction-induced increases of POMC mRNA in the anterior pituitary were absent in the rats which received morphine. (3) Morphine significantly increased POMC mRNA levels in the hypothalamus; water restriction had no effect. The morphine-induced increases in POMC mRNA in the hypothalamus were absent in the rat under the water restriction condition. These findings, that the effects of morphine on HPA activation or POMC mRNA expression depend on the presence of stress, suggest a counter-regulatory role of opiates on a stress response and opioid gene expression.

Adrenocorticotropic Hormone↗

PubMed2002

Maternal undernutrition during late gestation-induced intrauterine growth restriction in the rat is associated with impaired placental GLUT3 expression, but does not correlate with endogenous corticosterone levels.

Fetal intrauterine growth restriction (IUGR) is a frequently occurring and serious complication of pregnancy. Infants exposed to IUGR are at risk for numerous perinatal morbidities, including hypoglycemia in the neonatal period, as well as increased risk of later physical and/or mental impairments, cardiovascular disease and non-insulin-dependent diabetes mellitus. Fetal growth restriction most often results from uteroplacental dysfunction during the later stage of pregnancy. As glucose, which is the most abundant nutrient crossing the placenta, fulfills a large portion of the fetal energy requirements during gestational development, and since impaired placental glucose transport is thought to result in growth restriction, we investigated the effects of maternal 50% food restriction (FR50) during the last week of gestation on rat placental expression of glucose transporters, GLUT1, GLUT3 and GLUT4, and on plasma glucose content in both maternal and fetal compartments. Moreover, as maternal FR50 induces fetal overexposure to glucocorticoids and since these hormones are potent regulators of placental glucose transporter expression, we investigated whether putative alterations in placental GLUT expression correlate with changes in maternal and/or fetal corticosterone levels. At term (day 21 of pregnancy), plasma glucose content was significantly reduced (P<0.05) in mothers subjected to FR50, but was not affected in fetuses. Food restriction reduced maternal body weight (P<0.001) but did not affect placental weight. Plasma corticosterone concentration, at term, was increased (P<0.05) in FR50 mothers. Fetuses from FR50 mothers showed reduced body weight (P<0.001) but higher plasma corticosterone levels (P<0.05). Adrenalectomy (ADX) followed by corticosterone supplementation of the mother prevented the FR50-induced rise in maternal plasma corticosterone at term. Food restriction performed on either sham-ADX or ADX mothers induced a similar reduction in the body weight of the pups at term (P<0.01). Moreover, plasma corticosterone levels were increased in pups from sham-ADX FR50 mothers (P<0.01) and in pups from ADX control mothers (P<0.01). Western blot analysis of placental GLUT proteins showed that maternal FR50 decreased placental GLUT3 protein levels in all experimental groups at term (P<0.05 and P<0.01), but did not affect either GLUT1 or GLUT4 protein levels. Northern blot analysis of placental GLUT expression showed that both GLUT1 and GLUT3 mRNA were not affected by the maternal feeding regimen or surgery. We concluded that prolonged maternal malnutrition during late gestation decreases maternal plasma glucose content and placental GLUT3 glucose transporter expression, but does not obviously affect fetal plasma glucose concentration. Moreover, the present results are not compatible with a role of maternal corticosterone in the development of growth-restricted rat fetuses.

Animals↗

PubMed2000

Food restriction prevents advanced glycation end product accumulation and retards kidney aging in lean rats.

ABSTRACT.: Tissue content of advanced glycation end products (AGE) increases with age and contributes to the changes in structure and function of the renal and cardiovascular systems. The effect of chronic food restriction on this AGE accumulation was investigated in lean WAG/Rij rats. A 30% food restriction performed from 10 to 30 mo in female rats reduced their mean body weight from 240 +/- 7 to 160 +/- 12 g, but did not modify their survival. AGE collagen content increased from 14.3 +/- 5.5 to 104.7 +/- 13.0 arbitrary units per microgram (AU/microg) of hydroxyproline (OHPro) in kidney between 10 and 30 mo, and from 9.7 +/- 1.2 to 310.6 +/- 34.6 AU/microg OHPro in the abdominal aorta. Food restriction reduced AGE accumulation to 21.4 +/- 3.3 and 74.6 +/- 16.5 AU/microg OHPro in kidney and aorta of 30-mo-old animals. Similar results were found for collagen prepared from isolated glomeruli (7.8 +/- 1.2, 81.2 +/- 16.1, and 10.3 +/- 4.3 AU/microg OHPro in 10-mo, 30-mo, and restricted 30-mo-old rats). Reduction of intrarenal and arterial AGE accumulation by food restriction was confirmed by immunostaining in optical microscopy. Age-related changes in arterial and kidney structures as polyuria and proteinuria were mainly prevented by food restriction. These data indicate that chronic food restriction reduces the accumulation of AGE and preserves the structure and function of the renal and cardiovascular systems in learn rats, although it did not affect survival of the animals between 10 and 30 mo.

Animals↗

PubMedDate not supplied

Effect of restricted spinal motion on gait.

Spinal orthoses are common in the treatment of various conditions that affect the spine. They encompass both the spine and pelvis and thus have implications for pelvic and lower-limb motion during walking in addition to a direct effect on spinal motion. The role of the spine in walking is largely ill-defined, and the consequences of restricted spinal motion on walking have yet to be explored. This study investigated the effect of spinal restriction on gait in able-bodied persons. Gait analyses were performed on 10 able-bodied subjects as they walked at five different speeds that were distributed across their comfortable range of speeds. Data were collected during walking with and without spinal restriction by a fiberglass body jacket, which is similar to a thoracolumbosacral orthosis (TLSO). With spinal restriction, peak-to-peak (PP) pelvic obliquity and rotation were significantly reduced across all walking speeds (p < 0.001), while PP pelvic tilt was significantly reduced at only the fastest walking speeds (p = 0.017). PP hip abduction-adduction motion was significantly reduced with spinal restriction across all speeds (p < 0.001), while PP hip flexion-extension significantly increased at only the slow and very slow speeds (p < 0.001 and p = 0.023, respectively). A better understanding of the effects of restricted spinal motion on gait may help clinicians predict and avoid development of additional problems from TLSO use or surgical restriction of spinal motion. An awareness of these issues will enable clinicians to monitor patients for problems that may result from decreased spine and pelvic motion.

Adult↗

PubMed1998

Effect of exercise training and food restriction on endothelium-dependent relaxation in the Otsuka Long-Evans Tokushima Fatty rat, a model of spontaneous NIDDM.

We investigated whether endothelial function may be impaired in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a model of spontaneous NIDDM. The effect of exercise training and food restriction on endothelial function was also studied. OLETF rats were divided into three groups at age 16 weeks: sedentary, exercise trained, and food restricted (70% of the food intake of sedentary rats). Otsuka Long-Evans Tokushima rats were used as the age-matched nondiabetic controls. Endothelium-dependent relaxation of the thoracic aorta induced by histamine was significantly attenuated in the sedentary or food-restricted rats, and exercise training improved endothelial function. Relaxation induced by sodium nitroprusside, a donor of nitric oxide, did not differ significantly among groups. Both exercise training and food restriction significantly suppressed plasma levels of glucose and insulin and serum levels of triacylglycerol and cholesterol and reduced the accumulation of abdominal fat. Insulin sensitivity, as measured by the hyperinsulinemic-euglycemic clamp technique, was significantly decreased in sedentary rats but was enhanced in exercise-trained and food-restricted rats. The urinary excretion of nitrite was significantly decreased in sedentary and food-restricted rats compared with nondiabetic rats and was significantly increased in exercise-trained rats. These results indicate that exercise training, but not food restriction, prevents endothelial dysfunction in NIDDM rats, presumably due to the exercise-induced increase in the production of nitric oxide.

Abdomen↗

PubMed1994

Effects of restricted feeding on growth performance and carcass composition of lambs.

Fifty-eight crossbred lambs (26 kg BW) with moderate growth potential were used in a completely randomized design experiment to determine the effects of restricted feeding of all-concentrate diets on performance and carcass composition. Feeding levels studied were 100, 85, and 70% of ad libitum intake. Diets that were restricted-fed were formulated to have increased nutrient concentrations to provide equal daily intakes of protein, vitamins, and minerals among DM intake levels. Lambs were fed to a final weight that would yield carcasses of equal weight (24 kg). Average daily gain was reduced linearly (P < .02) and days on feed were increased linearly (P < .02) because of restricted feeding. Feed efficiency, however, was not affected by intake level. The quantity of separable lean tissue within carcass sides was increased (P < .05) with restricted feeding. Total separable fat within the side was reduced (P < .05) in an amount equal to the increase in lean tissue accretion. Chemical analysis of the carcass side showed a decrease (P < .05) in fat percentage and a corresponding increase (P < .05) in water percentage because of restricted feeding. Daily accretion rates of lean and bone tissue were not affected by restricted feeding; however, fat accretion was decreased linearly with decreasing feeding levels. Separable lean tissue within the primal cuts was generally increased with decreasing intakes, which led to a corresponding decrease in separable fat. Restricted feeding strategies can lead to the production of leaner carcasses. Reductions in fat content occur in the subcutaneous, seam, and mesenteric depot sites, but intramuscular fat content of consumable product also is reduced.

Animal Feed↗

PubMed2002

Effects of restricted versus conventional dietary adaptation on feedlot performance, carcass characteristics, site and extent of digestion, digesta kinetics, and ruminal metabolism.

Three experiments were conducted to determine effects of restricting intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in grain over a period of 20 to 22 d on overall cattle performance, carcass characteristics, digestibility, digesta kinetics, and ruminal metabolism. In Exp. 1, 84 Angus x Hereford yearling steers (initial BW = 418 +/- 29.0 kg) were fed for 70 d. Restricting intake during adaptation had no effect (P > 0.10) on overall ADG:DMI, but decreased (P < 0.05) DMI compared with ad libitum access to adaptation diets, which resulted from differences during the initial 28 d of the experiment. In Exp. 2, 150 mixed crossbred steer calves (initial BW = 289 +/- 22.9 kg) were fed for an average of 173 d. Restricting intake decreased (P < 0.01) overall daily gain (1.51 vs 1.65 kg/d) and DMI (8.68 vs 9.15 kg/d) compared with ad libitum fed steers; however, ADG:DMI was not influenced (P > 0.10) by adaptation method. Experiment three used eight ruminally and duodenally fistulated steers (initial BW = 336 +/- 20 kg) in a completely random design. Total tract digestibility, digesta kinetics and ruminal metabolism were determined. Restricting intake reduced (P < 0.10) daily DMI variation from d 1 through 7, 8 through 14, and 22 through 28 compared with ad libitum feeding of three adaptation diets. Restricted steers had reduced (adaptation method x period interaction, P < 0.05) intakes and fecal excretions of ADF and greater OM digestibilities on d 4 through 7, 11 through 14, and 18 through 21. Digesta kinetics and ruminal metabolism were generally not affected (P > 0.10) by adaptation method. Our results suggest that restricted-feeding of the final diet as a means of dietary adaptation can be used in finishing cattle with few problems from acidosis or related intake variation. In light-weight steers (Exp. 2), disruptions in intake during the adaptation period might have resulted in restriction for an extended period, which decreased (P < 0.01) hot carcass weight compared with calves fed ad libitum. Effects of limit feeding during the initial 28 d of the feeding period on site and extent of digestion, digesta kinetics, and ruminal metabolism were minimal, supporting few differences in performance across the finishing period for yearling cattle.

Adaptation, Physiological↗

PubMed2004

Effect of dietary restriction, pregnancy, and fetal type on intestinal cellularity and vascularity in Columbia and Romanov ewes.

The objectives of this study were to evaluate intestinal cellularity and vascularity in mature ewes in response to dietary restriction and pregnancy status and to quantify the response of these variables to increased nutrient demand of fetal growth. In Exp. 1, 28 mature Dorset x crossbred white-faced ewes (61.6+/-1.8 kg initial BW) were fed a pelleted, forage-based diet. Treatments were arranged in a 2 x 3 factorial, with dietary restriction (60% restriction vs. 100% maintenance for respective states of pregnancy) and pregnancy status (nonpregnant, NP; d 90 and 130) as main effects. Dietary treatments were initiated on d 50 of gestation and remained at 60 or 100% maintenance throughout the experiment. Nonpregnant ewes were fed dietary treatments for 40 d. In Exp. 2, four Romanov ewes were naturally serviced (Romanov fetus and Romanov dam; R/R); two Romanov embryos per recipient were transferred to four Columbia recipients (Romanov fetus and Columbia recipient; R/C), and three Columbia ewes were naturally serviced (Columbia fetus and Columbia dam; C/C). In Exp. 1, dietary restriction and pregnancy status interacted with regard to maternal jejunal DNA concentration (P < 0.01), with restricted ewes having a greater DNA concentration (mg/g; fresh basis) at d 130. Vascularity (percentage of total tissue area) in the jejunum was increased (P < 0.06) as a result of dietary restriction and pregnancy status. Total microvascular volume ofjejunal tissue was not altered by dietary restriction and increased (P < 0.01) at d 130 of pregnancy. In Exp. 2, R/R ewes had less (P < 0.09) DNA (g) in the jejunum compared with R/C and C/C ewes. Jejunal vascularity (%) was increased (P < 0.05) in R/R ewes compared with R/C or C/C ewes, whereas total jejunal microvascular volume remained unchanged. These data demonstrate intestinal vascular density responds to changes in diet and physiological state. In addition, pregnancy increased total jejunal microvascular volume.

Animal Feed↗

PubMed2005

A simultaneous procedure for deriving selection indexes with multiple restrictions.

The formulas given in literature for the construction of restricted indexes were designed only for the imposition of a single restriction (zero, fixed, or proportional). This study presents both the theory and the methods of a simultaneous procedure for constructing indexes with single or multiple restriction(s). Numerical examples are given to verify the theoretical development and to demonstrate the implementation of the procedure. The simultaneous procedure presented brings the construction of various restricted indexes into a simple computational scheme. In addition to the use of the proposed procedure to handle multiple traits, it can be used to modify the growth curve of meat animals or the lactation curve of dairy animals, which generally requires simultaneous imposition of different restrictions on different stages of the curves. A misconception in the literature is that the variance of an index (b'Pb) is not equal to the covariance between an index and its net merit (b'Ga) when the index is a restricted one. This study showed generally that b'Pb and b'Ga are equal in the restricted or unrestricted case only when elements of b represent the original solutions from the index equations and are not equal when elements of b are expressed in terms of proportions.

Animals↗

PubMed2003

[Age-related changes of lipid peroxidation in food-restricted rats based on determination of phosphatidylcholine hydroperoxide in the plasma, liver and kidney by high-performance liquid chromatography with fluorometric post-column detection].

Age-related changes of phosphatidylcholine hydroperoxide (PCOOH) were investigated in male Dawley rats aged 3 to 18 months, either fed ad libitum or dietary restricted (maintained on 60% of ad libitum food intake). Although there are many reports dealing with age-related changes of lipid peroxidation, they were exclusively results obtained by the non-specific thiobarbituric acid method. In this study, we measured PCOOH as an index of oxidative stress by a specific assay method using high-performance liquid chromatography with fluorometric post-column detection. The PCOOH levels in ad libitum-fed rat plasma, liver and kidney increased with age. Dietary restriction significantly suppressed the age-related PCOOH accumulation in the plasma. In dietary restricted rat liver, PCOOH levels tended to be suppressed by the restriction. In dietary restricted rat kidney, they were not due to until 12 months of age, but the levels at 18-months of age were suppressed by the restriction. Life span is mainly influenced by pathologic lesions. The increase in PCOOH levels with age can cause biomembrane damage, and appears to be involved in the development of lesions. Suppression of PCOOH level by dietary restriction appears to suppress the morbid conditions which shorten life span.

Aging↗

PubMed2001

Caloric restriction and cancer.

In 1909 Moreschi observed that tumors transplanted into underfed mice did not grow as well as those transplanted into mice fed ad libitum. His finding stimulated a decade of research which showed that caloric restriction also affected negatively the growth of spontaneous tumors. Between 1920 and 1940 little work was done in this area, possibly because of limiting methodology. In the 1940s the laboratories of Tannenbaum (Chicago) and Baumann (Wisconsin) were able to design studies using defined diets and showed that the observed effect was due to caloric content of the diet independently of the source of calories. After another active decade research activity in the calorie-cancer area declined until it was reborn in the 1980s. By the 1980s knowledge of physiology and molecular biology had advanced enough to allow investigators to probe mechanisms underlying the calorie-cancer phenomenon. We now know that caloric expenditure (as work or exercise) will lead to reduced risk. Energy restriction enhances DNA repair and moderates oxidative damage to DNA. Energy restriction reduces oncogene expression as well. Over a half century ago, Boutwell noted that energy restriction in female rats resulted in adrenal hypertrophy and reduced weight of ovaries and uterus. He suggested that energy restriction resulted in "pseudohypophysectomy." We now know that adrenalectomy can negate the effects of caloric restriction. Caloric restriction also affects insulin metabolism and may influence gene expression. These recent observations should help us understand some of the basic mechanisms involved in establishment and proliferation of tumors.

Animals↗

PubMed1994

Dietary restriction modulates the norepinephrine content and uptake of the heart and cardiac synaptosomes.

The present study was designed to examine the effects of long-term dietary restriction on cardiac sympathetic nerves and neurotransmitter. The food intake of male, 6-week-old Fischer 344 rats was reduced to 60% of the intake of control rats fed ad libitum. The body and heart weights of rats diet restricted for 4.5 months were less than those of the ad libitum fed animals, while the heart weight to body weight ratios were higher. The norepinephrine (NE) content of hearts from restricted rats (1073 +/- 84 ng/g wet wt) was higher than controls (774 +/- 38 ng/g wet wt), although the total amount of NE per heart was unchanged. Similarly, the cardiac synaptosomal P2 fraction from restricted rats possessed a higher NE content (24.1 +/- 2.4 ng/mg protein) than the P2 fraction of ad libitum fed controls (13.7 +/- 1.3 ng/mg protein). The desmethylimipramine-sensitive norepinephrine uptake of the P2 fraction from restricted rats was significantly higher than that of control rats (9.44 +/- 1.33 vs 4.75 +/- 0.35 ng/mg protein/hr). The NE uptakes of the two groups were similar when uptake was normalized to endogenous NE levels. These results demonstrate that long-term dietary restriction affects cardiac sympathetic nerve endings and suggest that part of the beneficial action of life-long dietary restriction on the age-related decline in cardiovascular regulation may be related to changes in cardiac sympathetic nerves.

Animals↗

PubMed1985

Effects of feed restriction on growth and metabolism of replacement pullets.

The effects of feed restriction on lipogenesis, carcass composition, and protein utilization were investigated. Two feed restriction programs were used: restricted duration of feeding (RDF) whereby pullets had access to feed for 7 or 9 hr/day and restricted access to feed (ADF) in which feed was available on alternate days. A control group received the same diet as the restricted groups but on an ad libitum basis. The feeding programs were applied to a white egg and brown egg strain of commercial laying hens from 1 until 5 weeks of age or from 3 days (RDF) or 10 weeks (ADF) until 19 weeks of age. The ADF restriction resulted in 12 to 25% decrease in body weights at 5 weeks and 5 to 11% decrease in body weights at 18 or 19 weeks. The RDF depressed body weights 24% at 5 weeks and 2% at 18 weeks. The RDF and ADF increased hepatic malic enzyme and glutamic oxaloacetic transaminase activities in both age groups. Plasma uric acid and hepatic glutamic pyruvic transaminase were affected, but not consistently, by ADF. It is hypothesized that ADF and RDF lead to increased lipogenesis and increased utilization of amino acids as sources of energy. Under conditions of mild restriction, this may result in increased carcass fat content.

Adipose Tissue↗

PubMed1988

Effects of ad libitum versus restricted feeding on body composition and egg production of broiler breeders.

A 64-wk experiment was conducted in which the effects of ad libitum vs. restricted feeding were studied during the pullet-layer transition and laying periods. Broiler breeder females were reared through 23 wk of age according to the breeder's recommendation. At 24 wk of age the following four treatments were imposed: T1, fed restricted amounts of feed according to the breeder's management guide; T2, feed restricted from 24 to 32 wk of age (as in T1), then fed ad libitum; T3, fed ad libitum from 24 to 64 wk of age; and T4, fed ad libitum from 24 to 32 wk of age, then restricted to 85% of the average 24 to 32-wk consumption. Birds fed ad libitum during the pullet-layer transition period (T3 + T4) consumed an average of 37 g more feed per day and reached sexual maturity 14 days earlier than restricted birds (T1 + T2). Live body weight, carcass weight, carcass weight corrected to zero fat content, and percentage carcass fat were all significantly higher at first egg in ad libitum vs. restricted birds, but these differences were small. Birds fed ad libitum during lay (T2 + T3) produced more eggs, achieved a higher peak percentage hen-day production, consumed more feed, and contained more body fat at last egg than hens restricted during lay (T1 + T4). However, neither mortality, feed efficiency, egg weight, egg fertility, nor egg specific gravity was affected by treatment.

Animals↗