Effect Of Restricted Food Intake Research Articles

Effects of Feed Restriction on Lipid Dynamics and Reproduction in Northern Bobwhites

High annual and prenesting mortality rates (0.46-0.95) in northern bobwhites (Colinus virginianus) compel these birds to devote extraordinary effort and resources to reproduction. Bobwhites exhibit reproductive behavior characteristic of rapid multi-clutch and ambisexual polygamous mating systems. To better understand the physiological basis of the bobwhite's high reproductive capacity, we studied effects of restricted food intake on lean mass, lipids, and egg laying. We fed 48 bobwhites 3 levels of food intake including ad libitum (100%), and 60% and 80% of ad libitum. After 15 weeks of this protocol, we switched treatments for 50% of the birds in each treatment. Lipid levels were similar for 60% and 80% groups, but significantly greater for the 100% group. Egg laying was markedly depressed and delayed in food-restricted groups. Comparing quail in the 60% and 80% groups, the latter appeared to catabolize body lipids in order to lay eggs. Egg production rates (eggs bird- 1 day- 1) were 0.7 for 100% quail, 0.18 for 80% quail, and 0.03 for 60% quail. After switching treatments, subgroups allotted ad libitum food quickly recovered. The 60% and 80% subgroups reached constant egg production (0.6-0.7 eggs bird- 1 day- 1), and with lean mass and lipid levels (9.8%-13.9% of wet body mass) within 10 days of ad libitum feeding. We discuss partitioning of endogenous reserves for reproduction and importance of exogenous energy in quail ecology.

Bone porosity and longevity in early medieval Southern Croatia

Porosity of the skull and skeletal remains, especially of the orbital roof, are one of the most frequent pathological findings on ancient human skeletal remains. There are several presumed causes of this condition and anthropologists consider skull porosities as a marker of physical and nutritional stress. A total of 115 graves were discovered at the early-medieval graveyard near Zadar (Croatia) that contained 128 partially preserved skeletons. Average estimated age at death was 37.2 ± 12.6 years for men, 31.9 ± 13.9 for women, and 5.3 ± 3.6 years for subadults. Pathological bone porosity was analysed. Cribra orbitalia was observed on 21 skulls (28.7%), signs of temporal porosity were noticed on six skulls and signs of subperiosteal bleeding on three skulls. Nineteen skulls had bone porosities in other areas. There was a significant difference (p = 0.039) in achieved age of adults with and without cribra orbitalia as those with cribra orbitalia lived on average 8.1 years longer. The bone porosity was probably caused by malnutrition that might have had a beneficial effect on longevity of adults, similar to effects of restricted food intake on extending lifespan through epigenetic signatures influencing gene expression.

Effects of food restriction on steroidogenesis in dispersed adrenocortical cells from Yarrow’s Spiny Lizard (Sceloporus jarrovii)

Changes in energy balance can lead to functional alterations at all levels of the hypothalamic–pituitary–adrenal (HPA) axis. However, relatively little is known about how energy balance affects functional properties of adrenocortical cells themselves. We investigated effects of restricted food intake on sensitivity to ACTH and rates of steroidogenesis in adrenocortical cells isolated from growing female and male Yarrow’s Spiny Lizards (Sceloporus jarrovii). At the end of the feeding regimen, we assayed acute (3h) progesterone (P4), corticosterone (B), and aldosterone (ALDO) production in response to ACTH in dispersed adrenocortical cells. Food restriction depressed growth rate by about 50% in both males and females but did not alter baseline plasma B measured at 10weeks in either sex. At the cellular level, food restriction had the following effects: (1) increased basal B production in both sexes and basal ALDO production in males, (2) increased net maximal rates of production of P4, B, and ALDO in response to ACTH, and (3) no overall effect on adrenocortical cellular sensitivity to ACTH. There were modest sex differences: overall rates of P4 production were 46% greater in cells from females than from males, and in response to food restriction, the net maximal rate of ALDO production was 50% greater in cells from males than from females. Our results demonstrate that food restriction in S. jarrovii increases adrenocortical cellular rates of steroid production without affecting overall cellular sensitivity to ACTH.

Chronic local inflammation in mice results in decreased TRH and type 3 deiodinase mRNA expression in the hypothalamic paraventricular nucleus independently of diminished food intake

During illness, changes in thyroid hormone metabolism occur, known as nonthyroidal illness and characterised by decreased serum triiodothyronine (T3) and thyroxine (T4) without an increase in TSH. A mouse model of chronic illness is local inflammation, induced by a turpentine injection in each hind limb. Although serum T3 and T4 are markedly decreased in this model, it is unknown whether turpentine administration affects the central part of the hypothalamus-pituitary-thyroid axis (HPT-axis). We therefore studied thyroid hormone metabolism in hypothalamus and pituitary of mice during chronic inflammation induced by turpentine injection. Using pair-fed controls, we could differentiate between the effects of chronic inflammation per se and the effects of restricted food intake as a result of illness. Chronic inflammation increased interleukin (IL)-1beta mRNA expression in the hypothalamus more rapidly than in the pituitary. This hypothalamic cytokine response was associated with a rapid increase in local D2 mRNA expression. By contrast, no changes were present in pituitary D2 expression. TSHbeta mRNA expression was altered compared with controls. Comparing chronic inflamed mice with pair-fed controls, both preproTSH releasing hormone (TRH) and D3 mRNA expression in the paraventricular nucleus were significantly lower 48 h after turpentine administration. The timecourse of TSHbeta mRNA expression was completely different in inflamed mice compared with pair-fed mice. Turpentine administration resulted in significantly decreased TSHbeta mRNA expression only after 24 h while later in time it was lower in pair-fed controls. In conclusion, central thyroid hormone metabolism is altered during chronic inflammation and this cannot solely be attributed to diminished food intake.

Effect of Restricted Food Intake on Production, Catabolism, and Effects of IGF-I and Cyclic Nucleotides in Cultured Ovarian Tissue of Domestic Nutria (Myocastor coypus)

The aims of these in vitro experiments were to examine the effects of short-term food restriction on ovarian secretory activity and the role of IGF-I and cAMP- and cGMP-dependent intracellular mechanisms in the control of ovarian function in domestic nutria. Slices of ovary from sexually mature animals kept under conditions of normal and restricted (12 of standard ration) feeding were cultured with or without IGF-I (50 ng/ml), cAMP analogues (dbcAMP and Rp-cAMPS), and cGMP analogues (8-pCPT-cGMP and Rp-8-Br-PET-cGMPS; all at 100 nM). In nonovarian cells dbcAMP activates and Rp-cAMPS inhibits protein kinase A, while 8-p-CPT-cGMP activates and RP-8-Br-PET-cGMPS inhibits protein kinase G and cGMP-gated ion channels. IGF-I release and catabolism, as well as the release of progesterone (P), estradiol (E), and cAMP by the cultures, were evaluated using RIA. IGF-I did not affect cAMP release, while each of the cAMP and cGMP analogues inhibited IGF-I release in both control and experimental groups. Fasting did not affect cAMP or IGF-I release. It partially prevented the effect of Rp-cAMPS, but not of other cyclic nucleotides, on IGF-I release and inhibited IGF-I catabolism. The Rp-cAMPS and Rp-8-Br-PET-cGMPS also inhibited IGF-I catabolism and the effects were greater with tissue from food-restricted than control animals. Ovaries from the underfed nutria secreted significantly more P and less E than those from normally fed animals. IGF-I and both cAMP analogues, given alone, did not affect P release whereas a combination of IGF-I and Rp-cAMPS increased P output in control, but not in the experimental group. The 8-pCPT-cGMP had no effect P release. Rp-8-Br-PET-cGMPS, given alone or in combination with IGF-I, dramatically increased P secretion by tissue from control but not underfed animals. Estradiol secretion by tissue from underfed animals was stimulated by IGF-I, dbcAMP, Rp-cAMPS, 8-pCPT-cGMP, and Rp-8-Br-PET-cGMPS as well as by combinations of IGF-I and Rp-cAMPS or Rp-8-Br-PET-cGMPS; these effects were not seen with control tissue. The results demonstrate that: (1) ovaries of domestic nutria secrete IGF-I, P, E, and cAMP; (2) cAMP and cGMP can influence IGF-I release and catabolism; (3) the cyclic nucleotides may have an IGF-I-mediated effect on P and E output; (4) IGF-I and cyclic nucleotides can prevent the effect of undernutrition on E, but not on P release; (5) effects of cAMP and cGMP on P and E are probably not mediated by protein kinase A, protein kinase G, or cGMP-gated ion channels; and (6) food restriction can influence ovarian IGF-I catabolism, P, and E release and modulate the effects of cyclic nucleotides and IGF-I on steroidogenesis. It is concluded that ovarian secretory activity may be regulated separately by nutrition and the cyclic nucleotide-IGF-I system, and there may be functional interrelationships between these mechanisms.

Trophic response of the intestinal mucosa to inflammationin rats injected with turpentine: a study using pair-fed controls

The effects of restricted food intake and acute inflammation on the small bowel were studied, Wistar rats (250 g) were given subcutaneous injections of turpentine (TR) and compared to two control groups, at 18, 42 and 66 h. One was fed ad libitum (C), the other was pair fed (PF) with TR. The TR and PF rats showed hypoplasia of the jejunal mucosa with decreased protein and DNA contents at 42 h and 66 h. The hypoplasia resulted in a reduced villus height that was significantly different from the controls at 66 h (C: 468 ± 17, TR[66] : 376 ± 20, PF+66-: 258 ± 2.9 pm, P <0.001). This decrease in villus height was significantly greater in the PF rats than in the TR rats at 66 h. The crypt height/villus height (CN) ratio in the PF rats was greater than in the TR group at all times. However, the protein and DNA contents in the TR group were significantly higher than in the PF group at 42 h and 66 h (TR/PF+42- : 29.5 ± 1.9 vs 20.5 ± 2.0, P < 0.001, +66-: 25.8 ± 2.0 vs 16.6 ± 1.3 mg/10 cm, P < 0.001). Disaccharidase activities (sucrase and glucoamylase) per 10 cm jejunum at 66 h were significantly lower in the PF group than in the control and TR groups (sucrase mU/10 cm+66- C : 3090 ± 144, TR 2683 ± 479, PF 1969 ± 144, P < 0.001; glucoamylase mU/10 cm+66- 237 ± 25, TR 169 ± 40, PF 123 ± 5, P < 0.01). The N-aminopeptidase patterns in the TR and PF groups were similar. These data suggest that dietary restriction during acute inflammation is the main factor causing hypoplasia of the jejunal mucosa. However, acute inflammation has a trophic effect on the morphological and function of the mucosa. This effect is probably due to inflammatory mediators, whose synthesis is stimulated by turpentine.

Influence of restricted food intake on estrous cycles and pseudopregnancies in dogs

Abstract Objective To examine effects of restricted food intake on estrous cycle frequency, interestrus interval, and pseudopregnancy prevalence in dogs. Animals 28 female Labrador Retrievers. Procedure Dogs were paired by body weight when they were 6 weeks old and fed so that the limit-fed pair-mate received 75% of the amount of food offered to its maintenance-fed counterpart. Estrous cycle, interestrus interval, and pseudopregnancy data were recorded. Results Mean annual frequency of estrous cycles and duration of interestrus intervals did not differ between feeding groups. Prevalence of clinically evident pseudopregnancy was significantly greater among females that were maintenance fed, although results of endocrinologic testing did not identify a mechanism for this observation. Conclusions and Clinical Relevance Pseudopregnancy in dogs can be influenced by physiologic factors related to nutrition. Clinicians should consider a variety of physiologic and environmental factors when evaluating reproductive function in dogs. (Am J Vet Res 1999;60:820–825)

Tissue fatty acid deposition is influenced by an interaction of dietary oil source and energy intake level in rats

To investigate the net tissue fatty acid deposition in response to graded levels of energy restriction and modification of diet fatty acid composition, rats were randomly assigned into four dietary groups and fed for 10 weeks diets containing 40% as energy of either fish, safflower, or olive oil, or beef tallow, consumed ad libitum or energy restricted to 85% or 68% of ad libitum intake by reducing diet carbohydrate content. An additional eight rats were killed before the diet regimen, to provide baseline data from which fatty acid deposition rates were calculated. Body weight, and heart, liver and fat mass gains were decreased with energy restriction ( P<0.001). Olive oil feeding resulted in higher body weight gain ( P < 0.03) than tallow feeding, whereas fish oil feeding was associated with highest ( P < 0.007) liver weight and lowest ( P < 0.03) fat mass gains. Energy deficit-related differences in the deposition of stearic, linoleic, arachidonic, and docosahexaenoic acids in heart and palmitic and docosahexaenoic acids in liver were dependent on the dietary oil consumed ( P < 0.03). Similarly, interactive effects of restricted food intake and dietary oil type were found in the gain of palmitic, stearic, oleic, and linoleic acids in adipose tissue ( P < 0.01) when expressed in relation to the amount of each fatty acid consumed. These data suggest that energy intake level can influence the deposition pattern, as well as oxidation rate, of tissue fatty acids as a function of tissue type, fatty acid structure, and dietary fatty acid composition.

Effects of Restricted Food Intake on Neutral Lipid and Free Fatty Acid Levels in the Digestive Gland – Gonad Complex and Faeces of Biomphalaria glabrata (Gastropoda)

Effects of Restricted Food Intake on Neutral Lipid and Free Fatty Acid Levels in the Digestive Gland – Gonad Complex and Faeces of Biomphalaria glabrata (Gastropoda)

Zinc deficiency impairs T cell function in mice with primary infection of Heligmosomoides polygyrus (Nematoda).

This study was designed to determine whether severe zinc deficiency would prolong the course of a primary Heligmosomoides polygyrus infection in mice, and whether this could be related to impaired T cell function. Female BALB/c mice were fed a zinc-sufficient (Zn+; 60 mg/kg), a zinc-deficient (Zn-; 0.75 mg/kg) or an energy restricted (PF; 60 mg zinc/kg) diet. After four weeks, some mice in each dietary group were given a primary infection with 100 larvae; nutritional, parasitological and immunological parameters were assayed over the following five weeks. Liver zinc concentrations were significantly reduced in Zn- mice compared with Zn+ mice. In certain cases, PF mice also had reduced liver zinc concentrations, showing the negative effects of restricted food intake on zinc status. Zinc deficiency prolonged the course of a primary infection, with the effects being most evident five weeks post-infection when Zn+ mice had only 40% as many worms as Zn- mice. Parasite infection induced strong immunological responses in Zn+ mice in contrast to Zn- mice. The reduced production of IL-4 and IFN-gamma, the reduced peripheral eosinophilia and reduced serum levels of IgE and IgG1 in Zn- mice were attributed to the zinc deficiency, whereas the reduced delayed type hypersensitivity response to parasite antigen and reduced production of IL-5 were in certain instances attributed to reduced energy intake rather than zinc deficiency. These results show that zinc deficiency significantly impairs functions normally attributed to both Th1 and Th2 cell populations, and that these alterations are associated with elevated worm numbers in zinc-deficient mice.

Effect of restricted food intake before and/or after mating on FSH, LH and progesterone profiles in greyface ewes.

Low levels of food intake before or after mating are associated with increased ova wastage rates (Rhind, McKelvey, McMillen, Gunn and Elston (1989). The relationship between level of food intake, circulating progesterone concentrations and ova wastage rates in the ewe during the first 2 weeks after mating are poorly understood; low levels of food intake are associated with increased circulating progesterone concentrations and rates of ova wastage while low circulating levels of progesterone have also been shown to be associated with increased ova wastage. The aim of this experiment was to investigate the effects of undernutrition on circulating concentrations of the luteotrophic hormone, LH, and on progesterone and the relationship between the profiles of the two hormones, in order to better understand the mechanisms by which undernutrition affects embryo growth and survival.

Effect of restricted food intake, before and/or after mating, on the reproductive performance of Greyface ewes

ABSTRACTThe effect on the reproductive performance of Greyface (Border Leicester × Scottish Blackface) ewes of a low level food intake and associated loss of live weight from either 14 days before mating, or from the time of mating, until 11 to 26 days after mating, was investigated. Ewes (252) were allocated to one of three treatments with ewes within each treatment divided into two flocks (flock A: 16 ewes per treatment; flock B: 68 ewes per treatment). Ewes of treatment LL were given a ration providing proportionately 0·5 estimated metabolizable energy (ME) requirements for maintenance from 2 weeks before mating. Those of treatment HL were given a daily ration providing 1·5 estimated ME requirements for maintenance until mating and the restricted ration thereafter. Ewes of treatment HH were given the higher ration throughout the experimental period. Flock A ewes were slaughtered at 11 days post mating and flock B ewes at between 18 and 26 days post mating. Treatment differences in the ovulation rates of flock A ewes were not statistically significant but in flock B, ewes of treatment LL had a lower mean ovulation rate (1·81) than those of treatments HL (2·23) and HH (2·09) (P &lt; 0·001). The lower ovulation rate of LL ewes relative to HL ewes in flock B was reflected in a lower mean potential lambing rate per ewe pregnant than in the HL treatment (1·58 v. 1·79; P &lt; 0·01) and per ewe put to the ram (1·37 v. 1·65; P &lt; 0·01). HL ewes had a slightly lower mean potential lambing rate per ewe pregnant (1·79 v. 1·97; P &lt; 01) and per ewe put to the ram (1·65 v. 1·82; P &lt; 0·05) than HH ewes. Ova wastage rates of LL + HL and HH ewes were 0·26 and 014 (P &lt; 001) respectively at 24 days post mating. Values for LL and HL ewes (0·27 and 0·25 respectively) were not significantly different.Estimated mean conceptus lengths were 370, 500 and 1400 μin for LL, HL and HH ewes respectively (P &lt; 0·05).It is concluded that low food intake before mating reduced the mean ovulation rate and low intakes after mating compromised embryo growth rate and induced a higher rate of ova wastage; this increase in the incidence of ova wastage was not significantly exacerbated by the low levels of intake prior to mating.

The effect of restricted food intake and refeeding on the ovarian follicle population of the pre-puberal Wistar rat.

A 50 p. 100 restriction of food intake in female Wistar rats from day 21 to day 42 of life prevented ovulation and altered the size distribution and numbers of ovarian follicles. The rate of atresia of non-growing oocytes in primordial follicles was retarded resulting in more oocytes per ovary. The number of follicles initiated to grow was reduced. Semi-starved rats allowed free access to food from day 42 of life achieved the body weight of ad libitum-fed controls at 66 days of age. A delayed puberty occurred. The numbers of non-growing oocytes in primordial follicles per ovary declined but remained significantly greater than control values at 66 days of age. Refeeding increased the numbers of follicles undergoing growth but within the size distribution found in age-matched controls. Thus semi-starvation followed by refeeding rendered the ovary developmentally younger but only in terms of total oocyte numbers. The ovarian response to starvation and refeeding is discussed in relation to pituitary function and provides new information on the potential lability of the oocyte population.

The effect of restricted food intake on the size and composition of the ovarian follicle population in the Wistar rat.

A 50% restriction of food intake in female Wistar rats from Day 21 to Day 42 of life delays the onset of puberty, reduces ovarian size and alters the size and composition of the ovarian follicle population. Semistarvation reduced the rate of oocyte atresia resulting in significantly more oocytes per ovary. This was directly attributable to more oocytes in the nongrowing, primordial follicle pool. Limited food intake reduced the number of follicles initiated to grow (Stage 1) and also the number of follicles in the bilaminar stages of growth (Stage 2). The numbers of follicles in the larger growth compartments were not significantly different from control values, but invariably, vesicular follicles were atretic in restricted rats. In both the preantral stages of growth and in the primordial follicle pool, the changes parallel closely those found in hypophysectomized rodents.

The effects of dietary lead content and food restriction on lead retention in rats

The effects of restricted food intake and of various dietary lead contents on lead retention 1 1 “Retention” is used to express the proportion of ingested lead found in the carcass at slaughter. were studied in young rats. In three experiments the rats were given either unrestricted or restricted access to diets providing 200 or 400 mg lead/kg for 3 or 6 weeks. At the end of the experiments a sample of blood was taken and the rats were ashed. Lead was determined in blood and ash from the carcass. Food restriction always increased the retention of lead but not always the lead content of blood or carcass. The retention of lead was similar when the diet was supplemented with 50, 200 or 400 mg lead/kg. Lead supplementation at 200 or 400 mg/kg reduced food intake and growth but did not affect food conversion ratios. Blood lead was related to the rate of ingestion of lead. The effect of food restriction in reducing lead retention should be taken into account in interpreting the effects of lead exposure accompanied by dietary conditions which reduce appetite or food supply.

Effect of Food Restriction on Metabolic Alterations in “Control Animals” Used in Studies on Biotin-deficient Rats

Different types of “control animals” used in investigations on biotin-deficient rats have been studied. The effect of restricted food intake (10 g), offered as one, two, or four equal meals a day, on metabolic patterns of control animals was investigated. Although the rate of glycogen synthesis in livers of control animals was not altered, it was considerably greater in diaphragms of animals given a restricted amount of food than in animals fed ad libitum. This increase was even more significant in animals fed multiple meals. The synthesis in vitro of fatty acids from labeled glucose or acetate by adipose tissues from animals given a restricted amount of food as a single meal was greatly increased compared with animals fed ad libitum. This increase was less marked in animals given multiple meals. The present study shows that metabolic alterations are induced in control animals as a consequence of food restriction. In view of these findings the noncritical use of “pair-fed,” “pair-weighed” and “trained-fed” animals as “controls” in nutritional studies could lead to erroneous conclusions.

The Effect of Restricted Food Intake, Thiamin Deficiency and Riboflavin Deficiency on the Voluntary Consumption of Ethanol by the Albino Rat

The Effect of Restricted Food Intake, Thiamin Deficiency and Riboflavin Deficiency on the Voluntary Consumption of Ethanol by the Albino Rat

The Effect of Restricted Food Intake on the Life Span of Genetically Obese Mice

Three groups of animals were used to determine the effect of restricted food intake on the longevity of hereditary obese mice. Obese mice in group I were fed ad libitum for life. Obese mice in group II were on limited food intake from 6 weeks of age for life and the thin sibling controls of group III, were allowed unlimited food. The maximum mean weight for animals in group I was 83 gm, for animals in group II, 36 gm and for group III, 30 gm. The body weight associated with longer life span in genetically obese mice was in a range greater than that normally attained by non-obese controls but considerably less than that reached by obese mice allowed to eat ad libitum. The mean life span for obese mice fed ad libitum was 457 days, for restricted obese mice, 795 days and for the controls, 747 days. One hundred percent of the full-fed obese mice were dead by 667 days while 81% of the obese mice on limited food intake and 60% of the non-obese controls were still alive at 730 days. These results show that severe obesity resulting from overeating in animals whose genetic constitution favors overfeeding greatly shortens the life span of these animals.

Effect of Hypophysectomy of Growing Chicks upon Their Basal Metabolism.

Ablation of the pituitary gland of immature chickens results in a depression of the basal heat production, in males to 80%, in females to 60% of normal. Hypophysectomy results in a voluntary food consumption of one-third to one-half of normal. Restriction of the food intake of normal birds to the level of hypophysectomized birds results in a depression of the BMR of normal birds to about the level of their operated controls. These results suggest that basal heat production may be directly influenced by the level of food intake rather than by hypopituitarism. The possibility of indirect effect of restricted food intake has not been ruled out.