Ad Libitum Research Articles

Positive Effects of Aerobic-Resistance Exercise and an Ad Libitum High-Protein, Low-Glycemic Index Diet on Irisin, Omentin, and Dyslipidemia in Men with Abdominal Obesity: A Randomized Controlled Trial.

The aim of this research was to evaluate changes in body composition, adipokine levels, and dyslipidemia parameters in males with abdominal obesity following two distinct interventions: exercise alone and exercise combined with an ad libitum diet. This study included 44 males with abdominal obesity (mean age 34.7 ± 5.5 years, waist circumference [WC] 110.3 ± 8.5, BMI 32.0 ± 3.9), who were randomly assigned to three groups: an experimental group engaging in aerobic-resistance exercise (II, n = 16), an experimental group engaging in aerobic-resistance exercise combined with an ad libitum high-protein, low-glycemic index carbohydrate diet (III, n = 16), both interventions lasting 6 weeks, and a control group without interventions (I, n = 12). Body composition metrics (body mass index [BMI], waist circumference [WC], body fat [BF], abdominal fat [ABD]) and fat-free mass [FFM], along with biochemical blood analyses (irisin [IR], omentin [OMEN], glucose [GLU], insulin [INS], LDL- and HDL-cholesterol), were measured at baseline and after the 6-week intervention. The effects of the interventions on the analyzed variables across groups were assessed using mixed ANOVA tests with post-hoc comparisons. Effect size (ES) was also calculated using partial eta squared (ηp2). The intervention in group III resulted in a significant decrease in IR (p < 0.01, ηp2 = 0.03) by 41% and LDL-C (p < 0.01, ηp2 = 0.02) by 14%. These effects were associated with a reduction in BF (p < 0.01, ηp2 = 0.02) by 14%, ABD (p < 0.01, ηp2 = 0.03) by 31%, and WC (p < 0.01, ηp2 = 0.01) by 3%. In group II, decreases after 6 weeks of intervention were noted only in WC (p = 0.02, ηp2 = 0.01) by 1% and in INS (p < 0.01, ηp2 = 0.04) by 47%. No differences were found between groups. The use of low-glycemic index carbohydrates (p < 0.01, ηp2 = 0.06) and increased protein intake (p < 0.01, ηp2 = 0.30) led to changes in the fiber-to-energy value of the diet ratio (p < 0.01, ηp2 = 0.18) and a reduction in dietary energy value (p < 0.01, ηp2 = 0.13) by 23%, resulting in a greater energy deficit than in the II group. These findings highlight the effect of combining dietary and exercise interventions to achieve significant changes in body composition and metabolic parameters, even over a short period of intervention.

The Interplay of Exogenous Cannabinoid Use on Anandamide and 2-Arachidonoylglycerol in Anxiety: Results from a Quasi-Experimental Ad Libitum Study

The public is increasingly reporting using cannabis for anxiety relief. Both cannabis use and the endocannabinoid system have been connected with anxiety relief/anxiolytic properties, but these relationships are complex, and the underlying mechanisms for them are unclear. Background/Objectives: Work is needed to understand how the endocannabinoid system, including the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG), may be impacted by the main constituents of cannabis, Δ9-tetrahydrocannabinol (THC), and cannabidiol (CBD). Methods: The current study examined how the ab libitum use of products differing in THC and CBD affected AEA and 2-AG among 292 individuals randomly assigned to THC-dominant use (N = 92), CBD-dominant use (N = 97), THC + CBD use (N = 74), or non-use (N = 29). Results: The findings suggest that AEA levels do not change differently based on 4 weeks of cannabis use or by cannabinoid content, as AEA similarly increased across all conditions from study weeks 2 to 4. In contrast, AEA decreased at an acute administration session with product conditions containing any THC having greater AEA levels on average than the non-use condition. With regard to 2-AG, its levels appeared to primarily be affected by THC-dominant use, both acutely and over 4 weeks, when controlling for baseline cannabis use and examining study product use frequency among use conditions. Conclusions: Overall, the results continue to shed light on the complicated relationship between cannabinoid content and endocannabinoid production, and highlight the need for continued research on their interplay in human subjects.

Neurodegeneration: Effects of calorie restriction on the brain sirtuin protein levels

BackgroundCalorie restriction (CR) is suggested to activate protective mechanisms in neurodegenerative diseases (NDDs). Despite existing literature highlighting the protective role of Sirtuin (SIRT) proteins against age-related neurodegeneration (ND), no study has explored the total levels of SIRT 1, 3, and 6 proteins simultaneously in brain homogenates by ELISA following intermittent calorie restriction. Applying CR protocols in mice to induce stress, we aimed to determine whether ND would be more pronounced with ad libitum (AL) or with CR. MethodsMice were randomly assigned to ad libitum (AL), Chronic CR (CCR), or Intermittent CR (ICR) groups at 10 weeks of baseline age (BL). SIRT 1, 3, and 6 protein levels were measured in the homogenized whole-brain supernatants of 49/50 weeks old mice by the ELISA method. Neuronal morphology was evaluated by the cresyl violet on the hippocampus. Neurodegeneration (ND) was assessed by the fluoro-jade and ImageJ was used for quantifications. ResultsIn the ICR group, SIRT1 levels were elevated compared to both the AL and BL groups. Similarly, the CCR group exhibited higher SIRT1 values compared to the AL and BL groups. While SIRT3 levels were higher in both the ICR and CCR groups compared to the AL and BL groups, this disparity did not reach statistical significance. SIRT6 levels were also higher in the ICR group compared to both the BL and AL groups, with the CCR group showing higher values compared to the BL and AL groups as well. Image quantification demonstrated significant neurodegeneration in the AL group compared to the CCR and ICR group, with no observed alterations in nerve cell morphology and number. ConclusionThis study revealed that the levels of SIRT 1, SIRT 3, and SIRT 6 in brain tissue were notably elevated, and there was less evidence of ND at the 50-week mark in groups undergoing continuous calorie restriction and intermittent calorie restriction compared to baseline and ad libitum groups. Our findings illustrate that CR promotes increased SIRT expression in the mouse brain, thereby potentially mitigating neurodegeneration.

Does Pelleted Starter Feed Restriction and Provision of Total Mixed Ration Ad Libitum during Weaning Influence the Behavior of Dairy Calves?

Currently, in dairy farming, there is growing concern for the welfare of calves during the critical period between the separation from their dams and weaning. During weaning, rationed feeding is a practice used to improve feed efficiency and control the calves’ growth, but it could also have negative consequences associated with hunger and feed restriction behavior. One such consequence could be the performance by calves of stereotyped behaviors indicative of poor welfare, such as non-nutritive oral behaviors. We hypothesized that making a Total Mixed Ration (TMR) available to calves, in addition to the standard pelleted starter diet, thanks to its structural and nutritional characteristics, could help to focus the oral behavior of the subjects towards nutritional activities and therefore limit the development of stereotyped behaviors, even when the amount of starter is restricted. To test this hypothesis, 30 female Holstein calves (equipped with an accelerometer based on an ear tag), were randomly assigned to one of three treatments: a control diet (CTR) with an ad libitum calf starter but without TMR; Treatment 1 (TRT1) with both ad libitum calf starter and ad libitum TMR; Treatment 2 (TRT2) with ad libitum TMR and a restricted amount of a calf starter (50% of the intake starter of the control group day by day). All animals were kept in individual cages equipped with a slow-flow teat bucket apparatus for milk feeding and with access to separated buckets (one for drinking water, one for the starter, and one for the TMR) placed on the outside of the front gate of each cage. Sucking behavior, as well as resting, ruminating and activity behavior, was recorded individually from 7 days of life to weaning (63 d of age) by an automated monitoring system based on ear-tag accelerometers (SCR eSense, Allflex, Irving, TX, USA). The results showed that in the CTR group, there was a greater sucking activity compared to the TRT1 group (26.25 min/head/day vs. 16.83 min/head/day, p = 0.0181), while the TRT2 group showed intermediate values (20.41 min/head/day). We hypothesized that this increased sucking activity may be explained by the oral activity directed at sucking the Milk Bar tube observed only in CTR calves after complete consumption of available milk and could indicate a higher stress level than in the TRT1 group. The time spent resting was significantly lower for the CTR group compared to the TRT1 group (9.20 h/day vs. 11.15 h/day, p = 0.0049) while the TRT2 group was in an intermediate situation (10.65 h/day). Furthermore, the increase in time dedicated to rest observed in TRT1, in light of the good vitality of the calves shown by the daily patterns of resting behavior and daily activity, also seems to suggest an improvement in welfare conditions compared to calves receiving pelleted starter alone. Based on these results, we can deduce that providing TMR ad libitum in the diet of weaning calves could be an effective strategy to improve calf welfare due to the reduction in stereotyped oral activity. However, further studies are needed to establish threshold values useful for distinguishing physiological from pathological resting times in weaning calves raised in individual cages.

The Effects of Restricted and Ad Libitum Milk Feeding on Growth and Health of Calves

In recent years, there has been a growing concern among consumers regarding animal welfare and their requirements, leading to an increased interest in exploring new approaches to calf rearing. Therefore, the aim of this study was to investigate the effects of milk feeding levels on the growth, feed intake, and blood variables of group-raised calves during the suckling period. Ten Holstein calves, 5 in each group, were used in the study when they were five years old. The calves were acclimated to an automated feeder during the initial 19 days of the experiment, and their initial LWs were recorded after weighing them again. The study concluded upon weaning the calves when they were sixty years old, with a total duration of 36 days The calves in the first group (G1) were provided with a total of 4 L/day of milk replacer, divided into 2 L servings in the morning and evening. Conversely, calves in the second group (G2) were allowed a maximum intake of 12 L/day of milk replacer, mimicking the natural sucking behaviour, with feedings in the morning (05:00-08:00), midday (10:00-13:00), and evening (16:00-20:00). Despite no significant differences in the LW, total and daily LW gains, and body measurements averages between of the groups, calves in G1 consumed more starter feed compared to those in G2 (P

Time-restricted feeding modulates gene expression related with rhythm and inflammation in Mongolian gerbils

Time-restricted feeding (TRF) has the potential to modulate circadian rhythm and widely studied in humans and laboratory mice. However, less is known about the physiological responses to TRF in wild mammals. Here, we used Mongolian gerbils, Meriones unguiculatus, to explore the effect of 6-week TRF on gene expression related with circadian rhythm and inflammation. The TRF gerbils had higher cumulative food intake than the ad libitum (AL) group, but body mass, feeding frequency/time and metabolic rate did not differ between groups. In the hypothalamus, downregulation of rhythm-related genes Per3, Cry1 and Dbp was detected in the daytime-restricted feeding (DRF) group and Cry1 was downregulated in the nighttime-restricted feeding (NRF) group. In the liver, the expression of Per1/3, Rev-erbα/β and Dbp was lower, and Bmal1 was higher in the DRF than in AL group, while NRF gerbils showed no changes. In the colon, the expression of Bmal1 and Cry1 was higher but Per3, Rev-erbα/β and Dbp were lower in the DRF than in AL group. Further, the expression of inflammation-related genes such as NF-κB, IL-1β, IL-18 and Nlrp3 was lower in the liver of DRF gerbils, and IL-1β was lower both in the hypothalamus and liver of NRF gerbils. Moreover, the genes related with inflammation such as NF-κB, Nlrp3, IL-10/18/1β and Tnf-α were positively or negatively correlated with multiple rhythm-related genes in the central and peripheral organs. In conclusion, TRF, particularly DRF, could modulate rhythm-related genes in the central and peripheral tissues and reduce hepatic expression of inflammation-related genes in gerbils.

Responsiveness and Reliability of a Sipping Device to Measure Motivation in Normal-Weight Individuals and Bariatric Surgery Patients.

There is an urgent need to measure the motivation to taste a sweet fluid in order to determine the influence of sweet tastes on the potential choices and consumption of beverages in patients with obesity. Current methods utilize either survey instruments or arbitrary operant tasks. The sipometer enables the participant to utilize an actual ingestive behavioral response to measure motivation during access to beverages on either ad libitum (AL) or progressive time ratio (PR) schedules. We determined the sipometer's responsiveness and reliability as a test of change in motivation for sweet tastes after bariatric surgery. Participants (58 patients and 28 controls, BMI: 18.5-24.9 kg/m2) sham-consumed an aspartame-sweetened (S) and non-sweetened (N) beverage under AL and PR schedules at a pre-surgery/baseline and a 3-month and 24-month visit (patients only). Cumulative pressure (CumPres), a measure of effort, was the sum of the pressures exerted during sipping under each condition. Baseline CumPres for PRS was higher than ALS and ALN in patients (p < 0.03) and higher than PRN in controls (p = 0.009). At 3 months, CumPres did not differ amongst conditions in patients, but CumPres for PRS was higher than all other conditions in controls (p < 0.0005). There were no baseline group differences; however, patients' CumPres for PRS was lower than controls' at 3 months (p = 0.002). Patients' CumPres for PRS decreased non-significantly between the baseline and 3 months but increased at 24 months compared to 3 months (p = 0.025) and was no different from baseline. Controls' CumPres for PRS increased at 3 months (p = 0.0359), but CumPres for all conditions was correlated between visits (p's < 0.038). The sipometer is a reliable and sensitive measure of motivation to consume sweet beverages and may reflect changes in post-operative energy intake.

Dilution of broiler breeder diets with oat hulls prolongs feeding but does not affect central control of appetite

The parents of broiler (meat) chickens (ie, broiler breeders) are food-restricted until sexual maturity, ensuring good health and reproduction, but resulting in hunger. We investigated whether diets with added insoluble fiber promote satiety and reduce behavioral, motivational, and physiological signs of hunger. Ninety-six broiler breeders were fed 1 of 4 feed treatments (n = 24 per diet) from 6 to 12 wk of age: 1) a commercial diet fed to the recommended ration (R) or 2) ad libitum (AL), the same diet as R but mixed with oat hulls at 3) 20% (OH20%) or 4) 40% (OH40%). The R, OH20% and OH40% diets were approximately iso-energetic and resulted in mean 12 wk of age weights within 2.5% of each other (1.21 kg), while AL birds weighed 221% as much (2.67kg). At 12 wk of age, agouti-related protein (AGRP) expression, was, on average, more than 12 times lower in AL birds (P < 0.001) but did not differ between the fiber diet treatments and R. Pro-opiomelanocortin (POMC) expression, was, on average, over 1.5 times higher in AL birds, but was not statistically significantly affected by feed treatments (P = 0.33). In their home pens, AL birds stood/sat more, foraged less and fed more in total (P < 0.001) and OH40% birds spent longer feeding than R (P = 0.001). Motivation to forage tested by willingness to walk through water to access an area of wood shavings (without food) was not significantly affected by diet (P = 0.33). However, restricted birds were willing to cross in only 7.3% to 12.5% of tests. Mostly birds stayed on the start platform, where AL birds sat more than other treatments and OH40% birds reduced walking relative to R birds (P = 0.016). Across the behavioral and physiological measurements there was a dichotomy of effects in response to approximately iso-energetic diets differing in fiber. There were some potentially beneficial behavioral effects related to reduced foraging and walking. However, there was no evidence that these diets significantly improved physiological measures of satiety of broiler breeders.

A Modified Calculation of the Withdrawal Time and a Risk Assessment of Enrofloxacin in Micropterus salmoides after Its Ad Libitum Administration via Medicated Feed in the Commercial Aquaculture.

The present study investigated the residue depletion and WTs of EF and its main metabolite, ciprofloxacin, in largemouth bass after ad libitum administration in commercial fish farming based on statistical approaches. Samples collected at pre-determined time points were assessed using high-performance liquid chromatography. If the concentrations of medicine were less than the quantitative limit, they were set to be half of the limit of quantitative. The terminal elimination of the target compound was assumed to fit a one-compartment model. The statistical methods of Bartlett's test and Cochran's test were used to inspect the homogeneity of the log-transformed data. The lack-of-fit test and F-test were used to check the linearity of the regression line. Outliers were assessed using standardized residuals. The final WT was estimated using the 95% percentile with a 95% confidence level. The WTs of EF were calculated to be 46, 29, 33, 46, and 20 days for the muscle + skin, plasma, gill, kidney, and liver, respectively. After the risk assessment, the values of the hazard quotient were calculated to be far less than 1, indicating that the risk of residual EF was particularly low in the edible tissues of largemouth bass after medicine depletion for various WTs.

Unravelling the mechanisms underlying the social interaction effects on the feed efficiency of rabbits

The feed consumption and feeding patterns of group-housed livestock and their productive outputs can be affected by interactions among group members, such as competition for feeder access and aggression. The impact of competition is especially significant when feed restriction is implemented during the fattening stage, a common practice in rabbit farms to reduce mortality from digestive disorders during this period. The overall aim was to quantify the importance of social interaction effects at the genetic and environmental level on feed efficiency, feeding behaviour and social ranking traits in rabbit populations having access to electronic feeders whilst they were housed in groups during fattening. This was done by quantifying novel feeding behaviour (FB) and social ranking (SR) traits and by estimating the genetic parameters and genetic correlations between all combinations of direct and social effects of these traits and residual feed intake (RFI), an indicator of feed efficiency. These effects were estimated in animals fed either ad libitum (AL) or on a time-based feed restriction (R) and were selected for feed efficiency on these feeding regimes for six generations. We found that there were substantial social genetic and social litter effects on RFI and FB traits, manifesting as antagonistic relationships between direct and social genetic effects. These effects were stronger amongst the R, as opposed to the AL animals. Despite these antagonistic relationships, the large social genetic effects resulted in substantial heritable variation available for selection of these traits, and therefore feeding behaviour could be changed by genetic selection, especially for R animals. The indicators of an animal’s SR were also heritable and subject to social genetic effects and therefore may respond to selection. However, the phenotypic population mean would not change, because such traits are context−specific. The animals that took most of the feeding resources and had priority access to the feeder had a higher RFI, that is, they were less efficient, but they made their cage mates more efficient. This is the first time that the genetic correlations between direct effects of RFI and direct effects of FB and SR traits, as well as between social effects of RFI and direct effects of FB traits and SR traits, have been quantified. Results could help to understand the mechanisms by which an animal exerts its influence on the feed efficiency of its cage mates under different feeding regimes and assist in the development of breeding strategies.

Calorie restriction in mice impairs cortical but not trabecular peak bone mass by suppressing bone remodeling.

Calorie restriction (CR) can lead to weight loss and decreased substrate availability for bone cells. Ultimately, this can lead to impaired peak bone acquisition in children and adolescence and bone loss in adults. But the mechanisms that drive diet-induced bone loss in humans are not well characterized. To explore those in greater detail, we examined the impact of 30% CR for 4 and 8wk in both male and female 8-wk-old C57BL/6J mice. Body composition, areal bone mineral density (aBMD), skeletal microarchitecture by micro-CT, histomorphometric parameters, and in vitro trajectories of osteoblast and adipocyte differentiation were examined. After 8wk, CR mice lost weight and exhibited lower femoral and whole-body aBMD vs ad libitum (AL) mice. By micro-CT, CR mice had lower cortical bone area fraction vs AL mice, but males had preserved trabecular bone parameters and females showed increased bone volume fraction compared to AL mice. Histomorphometric analysis revealed that CR mice had a profound suppression in trabecular as well as endocortical and periosteal bone formation in addition to reduced bone resorption compared to AL mice. Bone marrow adipose tissue was significantly increased in CR mice. In vitro, the pace of adipogenesis in bone marrow stem cells was greatly accelerated with higher markers of adipocyte differentiation and more oil red O staining, whereas osteogenic differentiation was reduced. qRT-PCR and western blotting suggested that the expression of Wnt16 and the canonical β-catenin pathway was compromised during CR. In sum, CR causes impaired peak cortical bone mass due to a profound suppression in bone remodeling. The increase in marrow adipocytes in vitro and in vivo is related to both progenitor recruitment and adipogenesis in the face of nutrient insufficiency. Long-term CR may lead to lower bone mass principally in the cortical envelope, possibly due to impaired Wnt signaling.

Omega-3 Status Evaluation in Australian Female Rugby League Athletes: Ad Libitum Fish Oil Provision Results in a Varied Omega-3 Index.

Optimal omega-3 status, influenced by increased intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is vital for physiological health. This study investigated the impact of ad libitum fish oil supplementation on the omega-3 status of female athletes in a professional rugby league team during a competitive season. Twenty-four (n = 24) athletes participated, and their omega-3 status was assessed using the Omega-3 Index (O3I) and arachidonic acid (AA) to EPA ratio through finger-prick blood samples taken at the start and end of the season. They were given access to a fish oil supplement (PILLAR Performance, Australia) with a recommended daily dose of four capsules per day (2,160mg EPA and 1,440mg docosahexaenoic acid). At the beginning of the season, the group mean O3I was 4.77% (95% confidence interval [CI: 4.50, 5.04]) and the AA to EPA ratio was 14.89 (95% CI [13.22, 16.55]). None of the athletes had an O3I exceeding 8%. By the season's end, the O3I was a significantly increased to 7.28% (95% CI [6.64, 7.93], p < .0001) and AA to EPA ratio significantly decreased to a mean of 6.67 (95% CI [5.02, 8.31], p < .0001), driven primarily by the significant increase in EPA of +1.14% (95% CI [0.77, 1.51], p < .0001). However, these changes were varied between the athletes and most likely due to compliance. This study has demonstrated that using the objective O3I feedback scale is possible with elite female rugby athletes, but individual strategies will be required to achieve daily intake targets of EPA + DHA.

A Randomized, Crossover Trial Assessing Appetite, Energy Metabolism, Blood Biomarkers, and Ad Libitum Food Intake Responses to a Mid-Morning Pecan Snack vs. an Equicaloric High-Carbohydrate Snack in Healthy Volunteers with Overweight/Obesity.

The differential effects of pecans versus other popular snack foods on appetite and blood markers of metabolism and satiety have not been well studied. This study investigated the effects of a single mid-morning snack of pecans or tortilla chips on subjective appetite, food intake, blood measures of hormones and metabolites, and resting energy expenditure. Twenty participants with overweight and obesity were enrolled in a within-participants, randomized crossover trial. Participants had indwelling catheters placed for blood sampling and were fed a standardized breakfast, followed two hours later by a 250 kcal snack of either pecans or tortilla chips, and then by a self-selected lunch. Visual analog scale (VAS) appetite measures, blood markers, and energy expenditure were taken at intervals after food consumption. VAS ratings, energy, food intake and macronutrient composition did not differ between treatment conditions, but glucose and insulin were significantly more elevated after tortilla chips. Free fatty acids (FFA), triglycerides (TG), peptide YY (PYY), and glucagon-like peptide-1 (GLP-1) were higher after consuming pecans compared to tortilla chips. Pecan consumption improves postprandial glucose and insulin profiles which would be beneficial to individuals at risk of developing type 2 diabetes. Further studies are needed to investigate whether increased relative secretion of PYY and GLP-1 after eating pecans versus tortilla chips may affect subjective appetite and energy intake if consumed chronically.

Intermittent fasting induced cerebral ischemic tolerance altered gut microbiome and increased levels of short-chain fatty acids to a beneficial phenotype

Preconditioning-induced cerebral ischemic tolerance is known to be a beneficial adaptation to protect the brain in an unavoidable event of stroke. We currently demonstrate that a short bout (6 weeks) of intermittent fasting (IF; 15 h fast/day) induces similar ischemic tolerance to that of a longer bout (12 weeks) in adult C57BL/6 male mice subjected to transient middle cerebral artery occlusion (MCAO). In addition, the 6 weeks IF regimen induced ischemic tolerance irrespective of age (3 months or 24 months) and sex. Mice subjected to transient MCAO following IF showed improved motor function recovery (rotarod and beam walk tests) between days 1 and 14 of reperfusion and smaller infarcts (T2-MRI) on day 1 of reperfusion compared with age/sex matched ad libitum (AL) controls. Diet influences the gut microbiome composition and stroke is known to promote gut bacterial dysbiosis. We presently show that IF promotes a beneficial phenotype of gut microbiome following transient MCAO compared with AL cohort. Furthermore, post-stroke levels of short-chain fatty acids (SCFAs), which are known to be neuroprotective, are higher in the fecal samples of the IF cohort compared with the AL cohort. Thus, our studies indicate the efficacy of IF in protecting the brain after stroke, irrespective of age and sex, probably by altering gut microbiome and SCFA production.

Resveratrol impinges on retrograde communication without inducing mitochondrial biogenesis in aged rat soleus muscle

The natural polyphenol resveratrol (RSV) might counteract the skeletal muscle age-related loss of muscle mass and strength/function partly acting on mitochondria. This work analysed the effects of a six-week administration of RSV (50 mg/kg/day) in the oxidative Soleus (Sol) skeletal muscle of old rats (27 months old). RSV effects on key mitochondrial biogenesis proteins led to un unchanged amount of SIRT1 protein and a marked decrease (60 %) in PGC-1α protein. In addition, Peroxyredoxin 3 (PRXIII) protein decreased by 50 %, which on overall suggested the absence of induction of mitochondrial biogenesis by RSV in old Sol. A novel direct correlation between PGC-1α and PRXIII proteins was demonstrated by correlation analysis in RSV and ad-libitum (AL) rats, supporting the reciprocally coordinated expression of the proteins. RSV supplementation led to an unexpected 50 % increase in the frequency of the oxidized base OH8dG in mtDNA. Furthermore, RSV supplementation induced a 50 % increase in the DRP1 protein of mitochondrial dynamics. In both rat groups an inverse correlation between PGC-1α and the frequency of OH8dG as well as an inverse correlation between PRXIII and the frequency of OH8dG were also found, suggestive of a relationship between oxidative damage to mtDNA and mitochondrial biogenesis activity. Such results may indicate that the antioxidant activity of RSV in aged Sol impinged on the oxidative fiber-specific, ROS-mediated, retrograde communication, thereby affecting the expression of SIRT1, PGC-1α and PRXIII, reducing the compensatory responses to the age-related mitochondrial oxidative stress and decline.

Benefits of calorie restriction in mice are mediated via energy imbalance, not absolute energy or protein intake

Caloric restriction (CR) results in reduced energy and protein intake, raising questions about protein restriction’s contribution to CR longevity benefits. We kept ad libitum (AL)–fed male C57BL/6J mice at 27°C (AL27) and pair-fed (PF) mice at 22°C (22(PF27)). The 22(PF27) group was fed to match AL27 while restricted for calories due to cold-induced metabolism. The 22(PF27) mice had significantly lower body weight, lean mass, fat mass, leptin, IGF-1, and TNF-α levels than AL27 mice (p<0.001 for all). Manipulations over ~11 weeks resulted in significant differences in body temperature, physical activity, and expression of key genes linked to hunger in the hypothalamus. Survival was significantly greater in 22(PF27) compared to AL27 overall (p<0.001). CR in the context of equivalent energy and protein intake resulted in hormonal, metabolic, and physiological benefits and extended longevity. Hence, energy imbalance, rather than low energy or protein intake per se, mediates the benefits of CR.

Glucose appetition in C57BL/6J mice: Influence of nonnutritive sweetener experience, food deprivation state and sex differences

In addition to its sweet taste, glucose has potent and rapid postoral actions (appetition) that enhance its reward value. This has been demonstrated by the experience-induced preference for glucose over initially preferred nonnutritive sweetener solutions in 24-h choice tests. However, some sweetener solutions (e.g., 0.8% sucralose) have inhibitory postoral actions that may exaggerate glucose appetition whereas others (e.g., 0.1% sucralose + 0.1% saccharin, S+S) do not. Experiment 1 revealed that food-restricted (FR) male C57BL/6J mice displayed similar rapid glucose appetition effects (stimulation of glucose licking within minutes) and conditioned flavor preferences following 1-h experience with flavored 0.8% sucralose or 0.1% S+S and 8% glucose solutions. Thus, the inhibitory effects of 0.8% sucralose observed in 24-h tests were not apparent in 1-h tests. Experiment 2 evaluated the effects of food deprivation state and sweetener concentration on glucose appetition in female mice. Unlike FR mice tested with 0.1% S+S and 8% glucose, ad libitum (AL) fed mice displayed no stimulation of 8% glucose licking in the 1-h tests. A second ad libitum group (AL) tested with 0.2% S+S and 16% glucose solutions displayed stimulation of 16% glucose licking by the third 1-h test. Both AL groups, like the FR group, developed a preference for the glucose-paired flavor over the S+S paired flavor. Thus, food restriction promotes increased glucose licking but is not required for a conditioned preference. The FR male mice (Exp. 1) and FR female mice (Exp. 2) showed similar appetition responses (licking stimulation and flavor preference) to 8% glucose.

Dietary restriction rescues 5-fluorouracil-induced lethal intestinal toxicity in old mice by blocking translocation of opportunistic pathogens

ABSTRACT Chemotherapy remains a major treatment for malignant tumors, yet the application of standard dose intensity chemotherapy is limited due to the side effects of cytotoxic drugs, especially in old populations. The underlying mechanisms of cytotoxicity and strategies to increase the safety and tolerance of chemotherapy remain to be explored. Using 5-fluorouracil (5-FU), a cornerstone chemotherapeutic drug, we demonstrate that the main cause of death in ad libitum (AL) fed mice after 5-FU chemotherapy was infection caused by translocation of intestinal opportunistic pathogens. We show that these opportunistic pathogens greatly increase in the intestine after chemotherapy, which was closely related to loss of intestinal lysozyme. Of note, two weeks of dietary restriction (DR) prior to chemotherapy significantly protected the loss of lysozyme and increased the content of the beneficial Lactobacillus genera, resulting in a substantial inhibition of intestinal opportunistic pathogens and their translocation. The rescue effect of DR could be mimicked by Lysozyme or Lactobacillus gavage. Our study provides the first evidence that DR achieved a comprehensive protection of the intestinal physical, biological and chemical barriers, which significantly improved the overall survival of 5-FU-treated mice. Importantly, the above findings were more prominent in old mice. Furthermore, we show that patients over 65 years old have enriched opportunistic pathogens in their gut microbiota, especially after 5-FU based chemotherapy. Our study reveals important mechanisms for the poor chemotherapy tolerance of the elderly population, which can be significantly improved by short-term DR. This study generates new insights into methods for improving the chemotherapeutic prognosis by increasing the chemotherapy tolerance and safety of patients with malignant tumors.

Intermittent Fasting Alters O2 Consumption and Body Composition in Young Rats: Comparative Analysis between Females and Males

Objectives: Intermittent Fasting (IF), time-restrictive food intake, has been shown to improve cognitive functions and reduce age-related behavioral impairments in rodent models. Our prior studies have found that IF intervention has significantly reduced body weights and food intake in male Fsher-344 rats; however, females did not display IF-induced declines in body weights and food intake. The exact mechanism for the sex differences in body weight and food intake during IF is not fully understood. Factors such as shifts in body composition and metabolic demand may contribute to variations in body weight shifts and food consumption. We hypothesized that changes in body composition and metabolic shifts may contribute to sex differences in body weight and food consumption in response to IF. Methods: Thirty-six, two-month-old male and female Fisher-344 rats were randomly assigned to four groups: ad libitum (AL) male, IF males, AL females, IF females. The AL group had 24/7 access to food and water while the IF group had 24/7 access to water and full access to food on an every-other-day basis for four weeks. After four weeks of IF intervention, rats were introduced to a metabolic rate (respiratory gas analyzer) and a grip strength test. In addition, body scans were performed using a Lunar Piximus rodent densitometer, (GE Lunar corporation). Group differences were analyzed with two-way ANOVA per Prism Graph Pad software. Following body scans, animals were euthanized, and tissues were sectioned, weighted, and stored for future analysis (brain, skeletal muscles, and adipose tissues). Results: IF intervention resulted in reduced body mass in males (vs. AL males, p&lt;0.0001) but not in females. Average daily food intake tended to be lowered in IF groups compared to their AL counterparts. Densitometry results revealed that the IF males had a decreased lean mass (vs. AL males, p&lt;0.0001) and fat mass (vs. AL males, p&lt;0.0001). Neither lean mass nor fat mass were changed in females as a result of IF. After two weeks of IF, O2 consumption was lowered in IF females compared to AL (P=0.0215 fed-state, P=0.0030 fast-state); however, no significant effect was seen in males. Grip strength was not significant among groups. Conclusions: In the present study, IF males significantly reduced body weights, as well as both fat and lean mass while females did not exhibit IF-induced changes. Interestingly, IF females displayed declines in oxygen consumption while males did not change. The decrease in oxygen consumption (slower metabolism) in IF females can be seen as a compensatory mechanism by the body to conserve energy and maintain body weights and composition shifts. The sexual dimorphic effect of body composition shifts is intriguing and the metabolic adaptations in skeletal muscle/fat tissues will be the focus of follow-up investigations. Funding source: P20GM113109 Cognitive and Neurobiological Approaches to Plasticity (CNAP) center. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A 2-Year Calorie Restriction Intervention Improves Diet Quality Without Compromising Nutritional Adequacy: The CALERIE Trial

Background: The Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE) was the first randomized controlled trial of calorie restriction (CR) on biomarkers of aging and cardiometabolic health in humans without obesity. Objective: To determine diet quality and nutritional adequacy during a 2y calorie restriction intervention among healthy adults without obesity. Design: CALERIE phase 2 was a multi-site, randomized controlled trial of 2y of CR vs. ad libitum (AL) control. CR participants received extensive dietary education and support. Food diaries were completed at baseline and months 6, 12, 18, and 24 and analyzed using NDSR. Diet quality was evaluated using the PANDiet diet quality index. Nutritional adequacy was defined using sex- and age-specific Estimated Average Requirement (EAR) or Adequate Intake (AI) criteria for each nutrient. Results: 220 participants completed baseline assessments and were randomized (145 CR, 75 AL; 70% women, age 38±7 y, BMI 25.1±1.7 kg/m2); 86% completed the 2y study. The level of calorie restriction achieved averaged 11.9±0.7% during the 2y intervention. Diet quality improved in the CR group (BL 74.3±5.1%; CR average 76.3±5.3%, p &lt; 0.0001), but not in the AL group ( p &lt; 0.0002 between groups). Nutritional adequacy improved modestly in CR, but not in AL. More than 90% of CR participants achieved 100% of EAR or AI during CR for protein, carbohydrate, 6 of 12 vitamins (A, B1, B2, B3, B6, B12), and 5 of 9 minerals (copper, iron, phosphorus, selenium, sodium). Nutrients for which &lt;90% of participants achieved adequacy included fiber, omega-3 fatty acids, vitamins B5, B9, C, E, and K, and the minerals calcium, magnesium, potassium, and zinc. Conclusion: A 2y CR intervention designed to promote healthy aging and comprised of comprehensive nutrition counseling promoted improvements in diet quality and maintenance or improvements in nutritional adequacy. This research was supported by grants U01AG020478, U01AG020480, U01AG020487, U01AG022132, U24AG047121, R33AG070455, and R01AG071717 from the National Institute on Aging. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.