Ad Libitum Group Research Articles

Time-restricted feeding prevents high-fat and high-cholesterol diet-induced obesity but fails to ameliorate atherosclerosis in apolipoprotein E-knockout mice.

One of the leading risk factors for atherosclerosis is obesity, which is commonly caused by a nutrient-rich Western-style diet, sedentary behaviors, and shift work. Time-restricted (TR) feeding and intermittent fasting are both known to prevent overweight and adiposity, improve glucose tolerance, and decrease plasma cholesterol in high-fat diet-induced obese mice. Here we examined the overall effects of TR feeding of a Western diet (fat, 40.5 Kcal%; cholesterol, 0.21 g%) using 8-week-old Apoe−/− mice. Mice were assigned into three groups: (1) an ad libitum (AL) group fed an AL Western diet, (2) a TR group with restricted access to a Western diet (15 h/day, 12:00 to 3:00 Zeitgeber time [ZT]); and (3) an Ex/TR group fed a TR Western diet and subjected to physical exercise at 12:00 ZT. Mice in the AL group gained body weight rapidly during the 14-week observation period. With TR feeding, excessive weight gain, liver adiposity, visceral fat, and brown adipose tissue volume were effectively suppressed. Although TR feeding failed to decrease Oil Red O-stained aortic plaques in Apoe−/− mice, physical exercise significantly decreased them. Neither TR feeding with exercise nor that without exercise decreased the mean area under the curve of the plasma cholesterol level or the fasting plasma glucose. Collectively, TR feeding of a Western diet prevented the development of obesity but failed to ameliorate atherosclerosis in Apoe−/− mice.

Abstract 13507: The Role of Weight Loss in Mediating the Effects of a 2-year Caloric Restriction Regimen on Cardiometabolic Risk Markers in Individuals Without Obesity

Introduction: Caloric restriction (CR) improves cardiometabolic risk, even among individuals without obesity. However, it is unclear whether these aging-related benefits are mediated by weight loss. Mediation analyses inform mechanisms underlying relationships between an exposure and outcome. Using mediation analyses, our aim was to test if 2-year weight loss mediates the beneficial effects of CR on cardiometabolic risk markers in individuals without obesity. Methods: Participants without obesity were randomized 2:1 to CR or ad libitum (AL) as part of the 2-year trial, Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE). The CR group aimed to enact 25% CR for 2 years, while AL maintained habitual energy intake. Baseline and year 2 assessments included weight and cardiometabolic risk markers. Using the approaches of Valeri and VanderWeele, mediation was quantified as the natural indirect effect (NIE), defined as the impact of an exposure on an outcome through a mediator. Here, the NIE was the effect of CR (exposure) on cardiometabolic risk markers (outcome) that was accounted for by weight change (mediator). Results: In total, 117 and 71 participants in the CR and AL groups, respectively, completed the trial. The CR group achieved 11.9 (± 0.7)% CR and 7.6 (± 0.3) kg of weight loss ( P < 0.01 versus AL). Weight loss significantly mediated the CR-induced improvements in total cholesterol (NIE = -10.4 ± 3.5 mg/dL), low-density lipoprotein cholesterol (NIE = -8.5 ± 2.8 mg/dL), high-density lipoprotein cholesterol (NIE = 2.9 ± 1.3 mg/dL), triglycerides (NIE = -0.20 ± 0.05 log mg/dL), the homeostatic model assessment of insulin resistance (NIE = -0.22 ± 0.06), and C-reactive protein (NIE = -0.39 ± 0.15 log ug/mL) ( P ≤ 0.02). Weight loss did not mediate CR-induced reductions in systolic (NIE = -0.9 ± 1.4 mmHg) and diastolic (NIE = -1.0 ± 1.1 mmHg) blood pressure ( P ≥ 0.37). Conclusion: In individuals without obesity, CR-induced improvements in multiple cardiometabolic risk markers are driven by weight loss after 2 years. These findings emphasize that, even in individuals without obesity, weight loss after prolonged CR plays a role in improving cardiometabolic disease risk; however, some CR benefits still occur independent of weight loss.

Calorie restriction delays cardiac senescence and improves cardiac function in obese diabetic rats.

The aims of this study were to investigate the impact of caloric restriction (CR) on cardiac senescence in an animal model of diabetes and examine the signal transduction mechanisms for changes in cell survival as well as cardiac function. Male 8-week-old Otsuka Long-Evans Tokushima fatty (OLETF) diabetic rats were divided into 2 groups: a group fed ad libitum (AL), and a group fed with CR (30% energy reduction). Long-Evans Tokushima Otsuka (LETO) non-diabetic rats were used as controls. LETO rats were divided into 3 groups: a high fat diet (HFD) group with a 22% increase in caloric intake, a CR group, and a group fed AL. At 40weeks of age, the telomere length was significantly shorter in the heart tissue of HFD rats but was not altered by CR in experimental rats with or without CR, however, telomerase activity in both strains of CR rats was significantly elevated. Protein expression of IGF-1, Sirt 1 and phospho-FoxO1 was increased in both CR groups. Echocardiography showed that CR preserved LV diastolic function with a significantly shorter E-wave deceleration time and a greater E/A ratio compared with the AL groups. These findings suggest that CR protocol increased telomerase activity without changing of telomere length, enhanced autophagy and improved LV diastolic function in animal model of diabetes rats. It is finally suggested that those impacts may be important for the maintenance of normal cardiac function and for delayed cardiac aging.

Lower Body Weight in Rats Under Hypobaric Hypoxia Exposure Would Lead to Reduced Right Ventricular Hypertrophy and Increased AMPK Activation.

BackgroundBoth chronic hypoxia (CH) and long-term chronic intermittent hypoxia (CIH) exposure lead to right ventricular hypertrophy (RVH). Weight loss is an effective intervention to improve cardiac function and energy metabolism in cardiac hypertrophy. Likewise, caloric restriction (CR) also plays an important role in this cardioprotection through AMPK activation. We aimed to determine the influence of body weight (BW) on RVH, AMPK and related variables by comparing rats exposed to both hypoxic conditions.MethodsSixty male adult rats were separated into two groups (n = 30 per group) according to their previous diet: a caloric restriction (CR) group and an ad libitum (AL) group. Rats in both groups were randomly assigned to 3 groups: a normoxic group (NX, n = 10), a CIH group (2 days hypoxia/2 days normoxia; n = 10) and a CH group (n = 10). The CR group was previously fed 10 g daily, and the other was fed ad libitum. Rats were exposed to simulated hypobaric hypoxia in a hypobaric chamber set to 428 Torr (the equivalent pressure to that at an altitude of 4,600 m above sea level) for 30 days. Measurements included body weight; hematocrit; serum insulin; glycemia; the degree of RVH (Fulton’s index and histology); and AMPK, mTOR, and PP2C expression levels in the right ventricle determined by western blotting.ResultsA lower degree of RVH, higher AMPK activation, and no activation of mTOR were found in the CR groups exposed to hypobaric hypoxia compared to the AL groups (p < 0.05). Additionally, decreased glycemia and serum insulin levels were observed. Interestingly, PP2C expression showed an increase in the AL groups but not in the CR groups (p < 0.05).ConclusionMaintaining a low weight before and during exposure to high-altitude hypoxia, during either CH or CIH, could prevent a major degree of RVH. This cardioprotection would likely be due to the activation of AMPK. Thus, body weight is a factor that might contribute to RVH at high altitudes.

Effects of Two Types of Calorie Restriction on Methylation Levels of Adiponectin Receptor 1 (AdipoR1) and Leptin Receptor Overlapping Transcript (Leprot) in a MMTV-TGF-α Breast Cancer Mouse Model.

The role of adiponectin and leptin signalling pathways has been suggested to play important roles in the protective effects of energy restriction (ER) on mammary tumour (MT) development. To study the effects of ER on the methylation levels in adiponectin receptor 1 (AdipoR1) and leptin receptor overlapping transcript (Leprot) genes using the pyrosequencing method in mammary fat pad tissue, mouse mammary tumour virus-transforming growth factor-α (MMTV-TGF-α) female mice were randomly assigned to ad libitum (AL), chronic ER (CER, 15 % ER) or intermittent ER (3 weeks AL and 1 week 60 % ER in cyclic periods) groups at 10 weeks of age until 82 weeks of age. The methylation levels of AdipoR1 in the CER group were higher than those in the AL group at week 49/50 (P < 0·05), while the levels of methylation for AdipoR1 and Leprot genes were similar among the other groups. Also, the methylation levels at CpG2 and CpG3 regions of the promoter region of the AdipoR1 gene in the CER group were three times higher (P < 0·05), while CpG1 island of Leprot methylation was significantly lower compared with the other groups (P < 0·05). Adiponectin and leptin gene expression levels were consistent with the methylation levels. We also observed a change with ageing in methylation levels of these genes. These results indicate that different types of ER modify methylation levels of AdipoR1 and Leprot in different ways and CER had a more significant effect on methylation levels of both genes. Epigenetic regulation of these genes may play important roles in the preventive effects of ER against MT development and ageing processes.

Calorie Restriction without Restricting Vitamins and Minerals Does Not Deteriorate Bones

Calorie restriction has a number of health benefits, however is associated with reduction of bone mineral density (BMD). As calcium and vitamin D are considered to be the most essential nutrients for bone health, this study aimed to determine if restriction of vitamins and minerals is the cause of this bone deterioration in calorie‐restricted diet. We hypothesize that calorie restriction without restricting the vitamins and minerals will not reduce bone mineral density in calorie‐restricted mice. To determine the effect of calorie restriction (CR) on bone mineral density, 6‐month‐old C57BL/6 female mice were fed AIN93 diet ad libitum (AL) or 20% CR for 8 months. Mice were divided into 2 groups: 1) Mice fed AL and 2) Mice fed 20% complete calorie restriction (CCR) where vitamins and minerals are also restricted. Mice were scanned with dual energy x‐ray absorptiometry (DXA) at the age of 6 month (baseline), and 14 month (after 8 months of experimental diet) and analyzed for the bone mass. Calorie restricted mice showed a noticeable reduction in BMD as compared to AL fed mice. To determine if long‐term calorie restriction without restricting vitamins and minerals can attenuate this bone deterioration in CCR mice after 8 months of experimental diet. Six‐month‐old C57BL/6 mice were divided into 2 groups: 1) Mice fed AL and 2) Mice fed 20% CCR for 8 months to induce bone loss. Then 20% CCR diet was replaced with 20% CR diet without restricting vitamins and minerals for another 8 months. Interestingly, reduction of BMD seen in CCR fed mice at the age of 14 month was attenuated at the age of 22 month when this group was fed for 8 months with 20% CR diet without restricting vitamins and minerals. In either case (vitamins and mineral restricted or not restricted), muscle mass, and strength were improved in 20% calorie restricted group as compared to AL group as determined by DXA, and wet weight at sacrifice for muscle mass and by rotarod performance test and endurance stress test for muscle strength. These data indicate that 20% CR without compromising vitamin and minerals could be a natural, cost effective and safe optimal dietary regimen that would improve muscle mass and strength without any deleterious effect on bone.Support or Funding InformationNIH NIA K01 KAG034233A and QNRF UREP23‐097‐1‐026

Modulation of feeding behavior and metabolism by dynorphin

The neuronal regulation of metabolic and behavioral responses to different diets and feeding regimens is an important research area. Herein, we investigated if the opioid peptide dynorphin modulates feeding behavior and metabolism. Mice lacking dynorphin peptides (KO) were exposed to either a normal diet (ND) or a high-fat diet (HFD) for a period of 12 weeks. Additionally, mice had either time-restricted (TR) or ad libitum (AL) access to food. Body weight, food intake and blood glucose levels were monitored throughout the 12-week feeding schedule. Brain samples were analyzed by immunohistochemistry to detect changes in the expression levels of hypothalamic peptides. As expected, animals on HFD or having AL access to food gained more weight than mice on ND or having TR access. Unexpectedly, KO females on TR HFD as well as KO males on AL ND or AL HFD demonstrated a significantly increased body weight gain compared to the respective WT groups. The calorie intake differed only marginally between the genotypes: a significant difference was present in the female ND AL group, where dynorphin KO mice ate more than WT mice. Although female KO mice on a TR feeding regimen consumed a similar amount of food as WT controls, they displayed significantly higher levels of blood glucose. We observed significantly reduced levels of hypothalamic orexigenic peptides neuropeptide Y (NPY) and orexin-A in KO mice. This decrease became particularly pronounced in the HFD groups and under AL condition. The kappa opiod receptor (KOR) levels were higher after HFD compared to ND feeding in the ventral pallidum of WT mice. We hypothesize that HFD enhances dynorphin signaling in this hedonic center to maintain energy homeostasis, therefore KO mice have a more pronounced phenotype in the HFD condition due to the lack of it. Our data suggest that dynorphin modulates metabolic changes associated with TR feeding regimen and HFD consumption. We conclude that the lack of dynorphin causes uncoupling between energy intake and body weight gain in mice; KO mice maintained on HFD become overweight despite their normal food intake. Thus, using kappa opioid receptor agonists against obesity could be considered as a potential treatment strategy.

The effect of feeder system and diet on welfare, performance and meat quality, of growing-finishing Iberian × Duroc pigs under high environmental temperatures

The present study investigated the replacement of 5% of starch (ST) by 5% of sunflower oil (SO), with or without feed restriction, in the diet of growing-finishing Iberian × Duroc pigs exposed to heat stress conditions. The effects of these strategies on the welfare, performance and meat quality of the animals were evaluated. Seventy-two crossbred males [51.00 ± 6.29 kg body weight (BW)] were housed in collective pens and randomly distributed according to their initial BW in climate-controlled rooms under heat stress conditions (30–32 °C; 35%–50% humidity). The experiment was carried out in a randomized block design, in a 2 × 2 factorial design composed of two diets (control or oil) and two feed management (ad-libitum and restriction) types. The investigated treatments were: 1) control diet (5% ST × 0% SO) with ad-libitum feed intake, 2) oil diet (replacement of 5% of ST by 5% SO) with ad-libitum feed intake, 3) control diet with restriction feed intake, and 4) oil diet with restriction feed intake. The pigs’ behavior and dirtiness score were observed daily, and their performance was assessed weekly. Furthermore, three blood samples were collected from each animal for hemogram analysis during the period of study. The analysis of meat and carcass quality was performed 24 h post-mortem once the animals had reached an average BW of 130–140 kg. Statistical analyses were performed using the PROC MIXED and PROC GENMOD procedures of the Statistical Analysis System (SAS). The diet-regimen interaction produced no effects (P > 0.05) on the analyzed variables, except for behavior. Animals on the control diet associated with ad-libitum feed management spent more time in the lateral decubitus position and showed reduced activity. In addition, pigs fed ad-libitum and those that received the control diet displayed the highest level of dirtiness during the experiment. Evaluation of performance revealed that pigs receiving the oil diet showed reduced feed intake (P < 0.05) with no difference in average daily gain and consequently presented better feed conversion values compared to animals on the control diet. Furthermore, the oil diet resulted in a higher (P < 0.05) carcass yield as well as a higher oleic fat content in the meat. Pigs on restricted feeding management with lower body and carcass weights produced higher values of leanness percentage and carcass compared to animals in the ad-libitum group. In conclusion, the replacement of 5% of starch by 5% of sunflower oil in the pigs’ diet during high ambient temperatures improved the animals’ welfare, feed efficiency, and carcass characteristics.

Abstract WP138: Intermittent Fasting Prevents Ischemic Progression and Promotes Long-Term Recovery

Intermittent fasting (IF) showed a substantial benefit in preventing vascular complications in both humans and animal models. We currently evaluated the effect of IF on post-stroke ischemic progression and motor dysfunction. Cohorts of adult male C57BL/6 mice were subjected to IF (16 h fasting and 8 h feeding) or ad libitum (AL) feeding for 45 days. Mice were subjected to one hour transient middle cerebral artery occlusion (MCAO) on day 45. Infarct size was measured on day 1 and 7 with T2-weighted 4.5T magnetic resonance imaging and Image J software with multi FDF opener plugin. Post-stroke motor deficits were evaluated with rotarod and beam walk tests between days 1 to 14 of reperfusion. Long-term post-stroke survival (till 90 days of reperfusion) was noted in both groups. IF group showed a significant decrease in body weight (by ~5.3g), soft weight (by ~5.6g), and lean weight (~8.1g) compared to AL group as identified by DEXA scanning on day 45 (n=6/group, *p&lt;0.05 by ANOVA with Bonferroni’s multiple comparisons test). The IF group showed significantly decreased brain infarction at both day 1 and day 7 of reperfusion (AL group showed 43% and 39% infarct size on days 1 and 7 while IF group showed 24% and 7.5% infarction on days 1 and 7; n=6-8/group, *p&lt;0.05 by ANOVA with Bonferroni’s multiple comparisons test.) IF cohort also showed significant improvement in post-stroke motor dysfunction identified by fewer foot faults (beam walk test) and more time on rotarod between days 1 to 14 of reperfusion compared with AL cohort. At day 90 of reperfusion, IF mice showed a high survival rate than AL mice (08 of 10 IF mice survived while 04 of 10 AL mice survived). Thus, our studies show that IF significantly preconditions the brain against post-stroke damage and improves the long term functional outcome.

Restoration of the Renin–Angiotensin System Balance Is a Part of the Effect of Fasting on Cardiovascular Rejuvenation: Role of Age and Fasting Models

Intermittent fasting (IF) is an intervention that can be beneficial for health span and mitigate the risk of developing age-related cardiovascular diseases; however, the involved mechanisms are not well understood. The present study investigated the effects of IF regimens on the plasma level of angiotensin II (Ang II), and the expression of Ang II receptors (AT1aR and AT2R) and angiotensin-converting enzyme 2 (ACE2) in the heart and aorta of male, 3-, 12-, and 24-month-old Wistar rats fed ad libitum (AL), fed ad libitum and fasted 1 day per week (FW), or fasted every other day (EOD) for 3 months. Aging was associated with high circulating levels of Ang II, high level of AT1aR protein expression in the heart and aorta, and low level of AT2R protein expression in the heart and aorta. Both FW and EOD decreased Ang II levels (p < 0.01, p < 0.001) and AT1aR protein expression in the heart (p < 0.01, p < 0.001) and aorta (p < 0.001) of old rats. Both FW and EOD increased the expression of AT2R protein in the heart (p < 0.05 and p < 0.001, respectively). However, only EOD increased the expression of AT2R protein (p < 0.05) in the aorta. In the old group, both the FW and EOD regimens induced a significant increase in the expression of ACE2 protein in the heart (p < 0.01, p < 0.001 vs. age-matched AL group, respectively). The results suggest that a part of the recovery effect of fasting on cardiovascular system in old rats is mediated through restoration of the balance of renin-angiotensin system.

Effects of two types of energy restriction on methylation levels of adiponectin receptor 1 and leptin receptor overlapping transcript in a mouse mammary tumour virus-transforming growth factor-α breast cancer mouse model.

The role of adiponectin and leptin signalling pathways has been suggested to play important roles in the protective effects of energy restriction (ER) on mammary tumour (MT) development. To study the effects of ER on the methylation levels in adiponectin receptor 1 (AdipoR1) and leptin receptor overlapping transcript (Leprot) genes using the pyrosequencing method in mammary fat pad tissue, mouse mammary tumour virus-transforming growth factor-α (MMTV-TGF-α) female mice were randomly assigned to ad libitum (AL), chronic ER (CER, 15 % ER) or intermittent ER (3weeks AL and 1 week 60 % ER in cyclic periods) groups at 10weeks of age until 82weeks of age. The methylation levels of AdipoR1 in the CER group were higher than those in the AL group at week 49/50 (P < 0·05), while the levels of methylation for AdipoR1 and Leprot genes were similar among the other groups. Also, the methylation levels at CpG2 and CpG3 regions of the promoter region of the AdipoR1 gene in the CER group were three times higher (P < 0·05), while CpG1 island of Leprot methylation was significantly lower compared with the other groups (P < 0·05). Adiponectin and leptin gene expression levels were consistent with the methylation levels. We also observed a change with ageing in methylation levels of these genes. These results indicate that different types of ER modify methylation levels of AdipoR1 and Leprot in different ways and CER had a more significant effect on methylation levels of both genes. Epigenetic regulation of these genes may play important roles in the preventive effects of ER against MT development and ageing processes.

Effects of long-term intermittent versus chronic calorie restriction on oxidative stress in a mouse cancer model.

Calorie restriction (CR) is one of the most effective methods to prevent many diseases including cancer in preclinical models. However, the molecular mechanism of how CR prevents cancer is unclear. The aim of this study was to understand the role of oxidative stress (OS) in the preventive effects of different types of CR in aging mouse mammary tumor virus-transforming growth factor-alpha (MMTV-TGF-α) female mice. Mice were enrolled in ad libitum (AL), chronic CR (CCR, 15% CR) or intermittent CR [ICR, 3 weeks AL (ICR-Refeed, ICR-RF) and 1 week 60% CR (ICR-Restriction, ICR-R) in cyclic periods] groups started at the age of 10 weeks and continued until 81/82 weeks of age. Blood samples were collected to measure malondialdehyde (MDA), glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) levels. There was no significant difference for MDA levels among the dietary groups although the chronic calorie restriction (CCR) group had lower MDA levels compared to intermittent calorie restriction (ICR) and AL group at different time points. There was also no change in MDA levels of CCR group with aging. On the other hand, the CCR group had higher CAT and SOD activity compared to ICR-R, ICR-RF, and AL groups. Moreover, GSH level was higher in CCR compared to ICR group at week 49/50 (p < .05). CAT and SOD activities were also positively correlated (p < .05). Here, for the first time, the long-term (72 weeks) effects of different types of CR on OS parameters were reported. In conclusion, moderate that is, 15%, CCR is more likely to be protective compared to the same overall calorie deficit implemented by ICR against OS that may play role in the preventive effects of CR.

Change in self-efficacy, eating behaviors and food cravings during two years of calorie restriction in humans without obesity

Calorie restriction (CR) enhances longevity in humans who are normal weight, overweight and obese. While dietary regimens can change self-efficacy, eating behaviors, and food cravings in individuals with obesity, the responses of these measures to prolonged CR in individuals who are exclusively not obese is unknown. The aim of this analysis was to test the effects of a two-year CR intervention on self-efficacy and eating attitudes and behaviors in humans without obesity by analyzing data from the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE 2) study. Participants (n = 218, BMI range = 21.3–29.0 kg/m2) were randomized to a 25% CR group or an ad libitum (AL) group. Eating attitudes and behaviors and self-efficacy were assessed using validated questionnaires at baseline, month 12, and month 24. Dietary restraint and self-efficacy increased in the CR compared to the AL group (ES ≥ 0.32). Increased self-efficacy was negatively related to weight change (ρ < −0.24). In the CR group, males showed a reduction in cravings for carbohydrates and fats at month 24, whereas females did not. The CR group showed elevations in state hunger, which were transient, and disinhibited eating (ES ≥ 0.37). In individuals without obesity, dietary restraint and self-efficacy could be important in promoting long-term CR for individuals looking to use CR as a tool to improve longevity.

Time-Restricted Feeding a High-fat Diet in Mice Elevates Plasma Concentration of Saturated Fatty Acids but Reduces Concentrations of Multiple Amino Acids (OR27-02-19)

ObjectivesObesity and obesity-related disease contribute to health care costs and pose serious health risks. Rodent studies indicate that time-restricted feeding (TRF) may be effective in reducing adiposity and metabolic disease associated with obesity. However, the metabolic pathways impacted by TRF in the context of obesogenic, high-fat (HF) diets need clarity. In the present work we examined the metabolomic changes in plasma induced by TRF of a HF diet in mice compared to a HF diet eaten ad libitum (AL) vs AL intake of a low-fat (LF) control diet. MethodsMale mice (12 weeks old) were fed a LF-AL diet (16%en fat), a HF-AL diet (48%en fat) or a HF diet restricted to feeding for 12 hours per day during the dark phase (HF-TRF). In week 9 of the study, energy expenditure data were collected. After 12 weeks, animals were fasted and plasma collected for clinical chemistries and metabolomic analysis. Multivariate analysis was used to discriminate diet treatments in untargeted metabolomic data. ResultsEnergy expenditure measurements throughout the day showed a markedly reduced fasting respiratory exchange ratio (RER) in HF-TRF mice during the inactive (light) phase compared to AL groups. Measures of insulin resistance, while increased with HF-AL intake, were resolved in the HF-TRF group. Partial least squares discriminant analysis revealed plasma non-esterified fatty acids (NEFA) and amino acids (AA) to be important discriminators between diet treatments. TRF resulted in elevated NEFA concentrations of the saturated fatty acids (12:0 to 18:0) and the polyunsaturated fatty acids α-linolenic acid and linoleic acid compared to HF-AL. Conversely, the concentrations of aromatic and branched chain amino acids were reduced in HF-TRF mice compared to HF-AL mice. ConclusionsAlterations in plasma metabolites following TRF of a HF diet are consistent with greater lipid utilization during the inactive phase as reflected in the RER. Decreases in the aromatic and branched chain amino acid concentrations are consistent with improved insulin sensitivity in humans. Funding SourcesThis work was supported by USDA-ARS project 3062-51000-053-00D. Supporting Tables, Images and/or Graphs▪▪

Refeeding abolishes beneficial effects of severe calorie restriction from birth on adipose tissue and glucose homeostasis of adult rats.

Calorie restriction (CR) is an important intervention for reducing adiposity and improving glucose homeostasis. Recently we found that in rats, a severe calorie restriction (SCR) beginning at birth up to adult age promotes positive effects on cardiometabolic risk factors and heart. The aim of this study was to investigate the effects of this new model of SCR on adipose tissue and glucose homeostasis of rats and to evaluate the effects of refeeding. From birth to 90 d of age, rats were divided into an ad libitum (AL) group, which had free access to food, and a CR50 group, which had food limited to 50% of that consumed by the AL group. From this moment, half of the CR50 animals had free access to food (the refeeding group [CR50-R]), and the other half continued 50% restricted for an additional 90-d period. Food intake was assessed daily and body weight weekly. In the final week of the SCR/refeeding protocol, oral glucose and intraperitoneal insulin tolerance tests were performed. Thereafter, rats were sacrificed and visceral fat was collected and used for histologic and Western blot analysis. Findings from this study revealed that SCR beginning at birth and up to adult life promoted a large decrease in visceral adiposity; improvement in glucose/insulin tolerance; and upregulation of adipose proliferating cell nuclear antigen, sirtuin 1, peroxisome proliferator-activated receptor-γ, and adiponectin. Refeeding abolished all of these effects. SCR from birth to adult age promoted beneficial effects on adipose tissue and glucose homeostasis; whereas refeeding abolished these effects.

HSF1/HSP pathway in the hippocampus is involved in SIRT1-mediated caloric restriction-induced neuroprotection after surgery in aged mice

Postoperative cognitive dysfunction is common in the elderly. Endoplasmic reticulum stress (ER-stress) increases neuronal apoptosis after surgery, and chaperone molecules, such as heat shock proteins (HSPs), help reduce unfolded protein reactions, thereby promoting protein homeostasis. Mammal sirtuin1 (SIRT1)-mediated deacetylation of heat shock factor 1 (HSF1) upregulates HSF1 binding to the HSP70 promoter. Caloric restriction (CR) improves cognition in many neurodegenerative models. In this study, we evaluated whether CR improves impaired learning and memory after surgery by attenuating ER-stress in an SIRT1-dependent manner. Male 18-month-old C57BL/6J mice receiving a 12-week CR or an ad libitum (AL) diet pre-intervention were challenged with tibial open fracture surgery and anesthesia or no treatment. We found a significant protective effect of CR on memory in contextual fear conditioning test after surgery compared with the AL group. CR alleviated ER-stress and neuronal apoptosis in the hippocampus induced by surgery. CR increased HSP70 expression through the HSF1/HSP pathway in a SIRT1-mediated manner, and inhibition of SIRT1 in the hippocampus by lentivirus injection partially reduced the benefits of CR (increased HSP70, deacetylated HSF1, reduced ER-stress, and improved memory). Taken together, our results showed that CR alleviates memory impairment postoperatively via attenuation of ER-stress in the hippocampus in an SIRT1-dependent manner, and the SIRT1/HSF1/HSP70 pathway is involved in this process.

Involvement of PPAR\u03b3/FSP27 in the pathogenic mechanism underlying insulin resistance: tipping the balance between lipogenesis and fat storage in adult catch-up growth rats

BackgroundCatch-up growth in adult (CUGA) is characterized by visceral fat accumulation, ectopic lipid deposition and insulin resistance (IR). Here, we investigated the determinants of these pathophysiological consequences of CUGA.MethodsRats were divided into different groups: control rats were offered normal chow ad libitum (AL), while experimental rats were put on 4-week caloric restriction (CR) initially, followed by regaining weight-matched normal chow (RN) in the RN group. General characteristics of lipid metabolism, expression level of genes in visceral adipose tissue (VAT), and glucose infusion rate (GIR60–120) by the hyperinsulinemic-euglycemic clamp were examined.ResultsAfter CR, percentage of abdominal fat mass (AFM%) was lower in the RN group than in the AL group but no difference was observed in serum non-esterified fatty acid (NEFA). Expression of fat-specific protein 27 (FSP27) was decreased in the RN group, while the expression of peroxisome proliferator-activated receptors γ (PPARγ), the key lipogenic gene, was increased. After refeeding, AFM% increased over time and serum NEFA persistently elevated in the RN group. Ectopic triglyceride contents were increased whereas insulin sensitivity was impaired. The expression of FSP27 did not follow the increase in the expression of PPARγ. Additionally, we observed a sustained increase in the expression of ATGL and CGI-58 in VAT in the RN group compared with the AL group after CR and refeeding, and a persistent shift-to-the-left of adipocyte size distribution accompanied by enhanced lipogenesis during CUGA.ConclusionThe persistent CR-induced imbalance of lipogenesis/fat storage capacity might be responsible for the CUGA-associated metabolic disorders.

Liver transcriptomic and proteomic profiles of preweaning lambs are modified by milk replacer restriction

Prenatal and early postnatal nutrition may promote long-term effects on both feed efficiency and health of animals. Therefore, moderated milk replacer restriction during the artificial rearing period might negatively affect feed efficiency during the postweaning phases in dairy ewes. The aim of this work was to identify differentially expressed (DE) genes by RNA sequencing and differentially accumulated proteins using MALDI-TOF mass spectrometry in the liver of artificially reared Assaf lambs to identify modified metabolic pathways as a consequence of milk replacer restriction in order to find possible solutions to correct any detrimental effect caused by this factor. Forty female Assaf lambs were used in this experiment. The animals were penned individually and assigned randomly to 1 of 2 treatments groups (n = 20 per treatment). The first group of lambs was fed ad libitum (AL), whereas the second (restricted, RES) only received approximately 62.5% of the level of intake measured in the AL group. Eight 35-d-old lambs from each group (16 lambs in total) were harvested and a piece of liver of 8 lambs (4 AL and 4 RES lambs) was excised for transcriptomic and proteomic analysis. Differential gene expression analysis identified 386 DE genes [198 of them being annotated genes in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway], with 176 downregulated and 210 upregulated in the early feed-restricted group relative to the AL group. A total of 26 spots were also differentially accumulated proteins in the liver of the 2 groups of lambs, 10 of them being down-accumulated whereas the other 16 evolved in the opposite way in the liver of RES relative to AL lambs. Collectively, both the transcriptomic and proteomic approaches revealed an upregulation of genes participating in oxidation of fatty acids in the early feed-restricted lambs. The expression of many genes involved in the degradation of several AA (e.g. alanine, valine, isoleucine, tyrosine) was also modified in the RES lambs, probably to render substrates for gluconeogenesis. Moreover, other genes involved in apoptosis, inflammation, or hepatic oxidative pathways were upregulated in these lambs. Finally, the expression of genes implicated in oxidative phosphorylation was modified in RES animals. Altogether all these modifications suggest that the partitioning and utilization of nutrients in the early feed-restricted lambs might have been modified, being partially responsible for changes during the replacement phase later in life.

Performance and changes in body composition of broiler chickens depending on feeding regime and sex

The differences in the performance, carcass parts, and internal organs of broiler chicken females and males fed ad libitum or restricted by 80 and 65% ad libitum were evaluated. Ross 308 males and females (2430 chickens) were fed ad libitum (ADL) or were restricted in days 8–14 of age by 80% ADL (R1) and 65% ADL (R2), respectively. Feed restriction depressed the live weight (P ≤ 0.001) in both sexes. Both sexes compensated for growth, and at the end of the fattening at 35 days, the restricted males (–3% R1 and –6% R2) and females (–3% R1 and –4% R2) were not significantly lighter than the ADL chickens. Feed intake was lower (P ≤ 0.001) in females than in males, and feed restriction and sex did not affect the feed conversion ratio. The growth of internal organs as early-developing tissues (heart, gizzard, liver) was less affected than the growth of late-developing tissues (breast, thigh, abdominal fat). Restricted males and females had more abdominal fat than the ad libitum chickens (P ≤ 0.05). Differences in allometric growth between males and females were in the liver, breast, and thigh. At the end of the experiment, restricted males had a higher weight of breast and thigh, whereas in females, the weights of both parts were similar to those of the ADL group. During the restriction period, the growth of internal organs is given priority compared to muscles, which was confirmed by allometric growth. Males showed a higher compensatory growth, including the growth of breasts and thighs.

Effect of Food Predictability on Life Span in Male Mice.

The purpose of this study is to compare the effect of unpredictable (U) or predictable (P) food delivery on health and longevity in mice. From 2 months of age until end of life, singly-housed male C57BL/6 mice were fed a semisynthetic diet either ad libitum (AL), or as imposed meals delivered as small pellets at either P or U times, frequencies, or amounts. The total daily food consumed by all groups was the same. The AL group gained body weight faster than either P or U groups, and had ~12% shorter median life span compared with either P or U groups. Bimonthly noninvasive body composition determinations showed that the differences in body weights were due to differences in fat and lean mass. Postmortem examinations revealed that the organ pathologies were similar in all groups, but a larger fraction of P and U mice were euthanized due to end-of-life suffering. There were no systematic differences in outcome measures between P and U groups suggesting that, within the range studied, the temporal pattern of food delivery did not have a significant metabolic effect.