Periods Of Food Deprivation Research Articles

Influence of Starvation on Respiratory Metabolism and Pyridine Nucleotide Levels in the Marine Dinoflagellate Oxyrrhis marina

Respiratory oxygen consumption rate (RO2) and potential respiration (Φ) has been monitored during a food deprivation period in the heterotrophic dinoflagellate Oxyrrhis marina. Φ was determined by measuring the activity of the enzymes from the electron transport system (ETS), the major contributor to the oxygen consumption in the cells. Additionally, we have quantified for the first time the concentration of pyridine nucleotides in this organism, both in their oxidized (NAD(P)(+)) and reduced forms (NAD(P)H). These molecules are the main electron donors at the beginning of the ETS. We observed a dramatic decrease in RO2 within the first days, whereas Φ steadily, but more gradually declined during the entire experiment. This led to a decrease of the RO2 /Φ with time. The intracellular total pool of NAD and NADP concentration, in turn, dropped exponentially in a manner parallel to the RO2. This strong decrease was mainly driven by a reduction in the concentration of the oxidized forms. The present work constitutes a first step in clarifying the role of intracellular NAD and NADP concentrations and the redox status in the control of in vivo RO2 in marine organisms.

Food Deprivation, Body Weight Loss and Anxiety-Related Behavior in Rats.

Simple SummaryFood deprivation protocols are frequently used in behavioral studies. However, there is limited evidence as to when food deprivation compromises animal welfare. Regarding the refinement of experiments involving animals, this study investigated the effects of food deprivation on body weight loss and behavior in male and female rats. Sex difference in behavior and motivational state after food deprivation is the main finding of the study. The data highlights the need for tailored pilot experiments to evaluate the impact of food deprivation on animals with regard to the 3Rs principles (replacement, reduction, refinement) in animal science.In behavioral studies, food deprivation protocols are routinely used to initiate or maintain motivational states that are required in a particular test situation. However, there is limited evidence as to when food deprivation compromises animal welfare. This study investigated the effects of different lengths of food deprivation periods and restricted (fixed-time) feeding on body weight loss as well as anxiety-related and motivated behavior in 5–6 month old male and female Wistar rats. The observed body weight loss was not influenced by sex and ranged between 4% (16 h deprivation) to approximately 9% (fixed-time feeding). Despite significant body weight loss in all groups, the motivation to eat under the aversive test conditions of the modified open field test increased only after 48 h of food deprivation. Long-lasting effects on anxiety as measured in the elevated plus maze test 24 h after refeeding have not been observed, although fixed-time feeding could possibly lead to a lasting anxiogenic effect in female rats. Overall, female rats showed a more anxiolytic profile in both tests when compared to male rats. Despite these sex differences, results suggest that food deprivation is not always paralleled by an increased motivation to feed in a conflict situation. This is an important finding as it highlights the need for tailored pilot experiments to evaluate the impact of food deprivation protocols on animals in regard to the principles of the 3Rs introduced by Russell and Burch.

MUSCLE WASTING AFTER 48 HOURS OF FOOD DEPRIVATION DIFFERS BETWEEN MOUSE STRAINS AND IS PROMOTED BY MYOSTATIN DYSFUNCTION

Background. Genetic factors play an important role in determining muscle mass. Indeed, myostatin dysfunction is associated with a pronounced muscle hypertrophy. The aim of our study was to test the hypothesis that starvation induced muscle wasting differs between BEH+/+ and C57BL/6J strains of mice and myostatin dysfunction prevents muscle wasting in BEH strain. Methods. 18-week-old males of C57BL/6J, BEH+/+ and BEH were subjected to 48 h food deprivation (FD). C57BL/6J mice were representatives of classic mouse strain. BEH mice which differ from BEH+/+ mice by Compact mutation in the Mstn gene represented a model for myostatin dysfunction. All mice were divided into experimental and control groups. The control groups consisted of mice fed ad libitum. Seven mice were studied in each group. Mice were weighed before as well as 24 h and 48 h after FD which was followed by dissection and weighing of the hindlimb skeletal muscle. Results. BEH and BEH+/+ mice showed a similar (16.9 ± 1.4% vs. 19.3 ± 2.4%, p > .05) loss of body mass while loss of body mass in C57BL/6J mice was the greatest (24.8 ± 1.9%, p < .001) after FD. The loss of muscle mass was significant in both BEH (p < .001) and C57BL/6J (p < .01) mice, but it was below the level of significance (p > .05) in BEH+/+ mice. Conclusions. Myostatin dysfunction promotes muscle atrophy after FD. During short periods of FD, BEH+/+ mice are more resistant to body and muscle loss compared to C57BL/6J mice.

Early life adversity increases foraging and information gathering in European starlings, Sturnus vulgaris.

Animals can insure themselves against the risk of starvation associated with unpredictable food availability by storing energy reserves or gathering information about alternative food sources. The former strategy carries costs in terms of mass-dependent predation risk, while the latter trades off against foraging for food; both trade-offs may be influenced by an individual's developmental history. Here, we consider a possible role of early developmental experience in inducing different mass regulation and foraging strategies in European starlings. We measured the body mass, body condition, foraging effort, food consumption and contrafreeloading (foraging for food hidden in sand when equivalent food is freely available) of adult birds (≥10 months old) that had previously undergone a subtle early life manipulation of food competition (cross-fostering into the highest or lowest ranks in the brood size hierarchy when 2–12 days of age). We found that developmentally disadvantaged birds were fatter in adulthood and differed in foraging behaviour compared with their advantaged siblings. Disadvantaged birds were hyperphagic compared with advantaged birds, but only following a period of food deprivation, and also spent more time contrafreeloading. Advantaged birds experienced a trade-off between foraging success and time spent contrafreeloading, whereas disadvantaged birds faced no such trade-off, owing to their greater foraging efficiency. Thus, developmentally disadvantaged birds appeared to retain a phenotypic memory of increased nestling food competition, employing both energy storage and information-gathering insurance strategies to a greater extent than their advantaged siblings. Our results suggest that subtle early life disadvantage in the form of psychosocial stress and/or food insecurity can leave a lasting legacy on foraging behaviour and mass regulation even in the absence of food insufficiency during development or adulthood.

Food Shortage Causes Differential Effects on Body Composition and Tissue-Specific Gene Expression in Salmon Modified for Increased Growth Hormone Production.

Growth hormone (GH) transgenic salmon possesses markedly increased metabolic rate, appetite, and feed conversion efficiency, as well as an increased ability to compete for food resources. Thus, the ability of GH-transgenic fish to withstand periods of food deprivation as occurs in nature is potentially different than that of nontransgenic fish. However, the physiological and genetic effects of transgenic GH production over long periods of food deprivation remain largely unknown. Here, GH-transgenic coho salmon (Oncorhynchus kisutch) and nontransgenic, wild-type coho salmon were subjected to a 3-month food deprivation trial, during which time performance characteristics related to growth were measured along with proximate compositions. To examine potential genetic effects of GH-transgenesis on long-term food deprivation, a group of genes related to muscle development and liver metabolism was selected for quantitative PCR analysis. Results showed that GH-transgenic fish lose weight at an increased rate compared to wild-type even though proximate compositions remained relatively similar between the groups. A total of nine genes related to muscle physiology (cathepsin, cee, insulin-like growth factor, myostatin, murf-1, myosin, myogenin, proteasome delta, tumor necrosis factor) and five genes related to liver metabolism (carnitine palmitoyltransferase, fatty acid synthase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, glucokinase) were shown to be differentially regulated between GH-transgenic and wild-type coho salmon over time. These genetic and physiological responses assist in identifying differences between GH-transgenic and wild-type salmon in relation to fitness effects arising from elevated growth hormone during periods of long-term food shortage.

A Novel Use for Potassium Alum as Controlling Agent Against Periplaneta americana (Dictyoptera: Blattidae).

In this work, we present our results on the use of potassium alum as an environmentally friendly insecticide. This compound has the potential to rid our homes, schools, hotels, restaurants, and ships of cockroach infestations. This compound is environmentally friendly and has no hazardous effects on plant, animal, or human ecosystems. Alum was approved for medical use a long time ago. In our laboratory, we developed a novel method using potassium alum as an environmentally friendly insecticide to kill the most common cockroach in the subtropical region, Periplaneta americana (L.). Adult and nymph-staged cockroaches were left to feed on potassium alum per individual insect after a period of food deprivation. The mortality was recorded as LT50. The younger nymphs the third and early fourth instars died within 4 d of feeding after consuming an average of 0.3 mg per individual insect. Gravid females were highly susceptible to alum toxicity and experienced a higher mortality rate, with an average of 3 mg per individual female. The oothecae of the normal untreated females were 8.1 mm long and 4.13 mm wide and weighed 94 mg. The eggs laid by the treated gravid females were underweight and exhibited a dwarfism shape, and these eggs did not hatched if the females consumed the potassium alum before laying eggs. The results revealed that the adult male and female cockroaches have to consume 1 mg and 2.7 mg, respectively, of potassium alum to kill 100% of them after 1 month of ingestion. The potassium alum had to be ingested by the cockroaches to affect mortality. The effect of potassium alum was attributed to chronic toxicity and not acute toxicity. The potential applications of this novel technique will be discussed.

Influences of Parental Care and Food Deprivation on Regulation of Body Mass in a Burying Beetle

AbstractChanges in adult body mass during breeding can reveal how parents prepare energetically for care, the stress of care, and the need to terminate care in a state conducive for future reproduction. Interpreting changes in parent mass can be difficult, however, because temporal variation in body mass may reflect a constraint imposed by the stress of care, revealing conflict within the family, or a shift to a new body mass optimum adaptive for a different stage of the breeding cycle. Here, we examined the effect of food deprivation and parenting on variation in female body mass of Nicrophorus orbicollis, an insect in which parents and offspring share a common food resource (a prepared carrion ball). Female parents demonstrated a remarkable degree of regulation of body mass: Despite varied periods of food deprivation (0–8 d) prior to discovery of a carcass, females attained a similar body mass (108.3–109.2% of pre‐deprivation mass) at the time of larval hatching. Females attained a greater body mass in anticipation of rearing a greater number of young. Mothers lost mass during active parental care, and mass at the end of caregiving was less in mothers that reared more and heavier young. Body mass at the end of care was less than the preferred mass for females searching for a carcass, indicating that the mothers sacrificed self‐maintenance and future reproductive potential for their current brood. Contrary to prediction, pre‐breeding food deprivation had no effect on offspring size or on female condition at the end of care. We conclude that there is a limited degree of conflict over the sharing of food among N. orbicollis parents and offspring, but that this conflict is not exacerbated by food deprivation prior to breeding.

Effect of Carbohydrate Supplementation on Investment into Offspring Number, Size, and Condition in a Social Insect.

Resource availability can determine an organism’s investment strategies for growth and reproduction. When nutrients are limited, there are potential tradeoffs between investing into offspring number versus individual offspring size. In social insects, colony investment in offspring size and number may shift in response to colony needs and the availability of food resources. We experimentally manipulated the diet of a polymorphic ant species (Solenopsis invicta) to test how access to the carbohydrate and amino acid components of nectar resources affect colony investment in worker number, body size, size distributions, and individual percent fat mass. We reared field-collected colonies on one of four macronutrient treatment supplements: water, amino acids, carbohydrates, and amino acid and carbohydrates. Having access to carbohydrates nearly doubled colony biomass after 60 days. This increase in biomass resulted from an increase in worker number and mean worker size. Access to carbohydrates also altered worker body size distributions. Finally, we found a negative relationship between worker number and size, suggesting a tradeoff in colony investment strategies. This tradeoff was more pronounced for colonies without access to carbohydrate resources. The monopolization of plant-based resources has been implicated in the ecological success of ants. Our results shed light on a possible mechanism for this success, and also have implications for the success of introduced species. In addition to increases in colony size, our results suggest that having access to plant-based carbohydrates can also result in larger workers that may have better individual fighting ability, and that can withstand greater temperature fluctuations and periods of food deprivation.

Telomere dynamics in wild brown trout: effects of compensatory growth and early growth investment.

After a period of food deprivation, animals often respond with a period of faster than normal growth. Such responses have been suggested to result in decreased chromosomal maintenance, which in turn may affect the future fitness of an individual. Here, we present a field experiment in which a food deprivation period of 24 days was enforced on fish from a natural population of juvenile brown trout (Salmo trutta) at the start of the high-growth season in spring. The growth of the food-deprived fish and a non-deprived control group was then monitored in the wild during 1 year. Fin tissue samples were taken at the start of the experiment and 1 year after food deprivation to monitor the telomere dynamics, using reduced telomere length as an indicator of maintenance cost. The food-deprived fish showed partial compensatory growth in both mass and length relative to the control group. However, we found no treatment effects on telomere dynamics, suggesting that growth-compensating brown trout juveniles are able to maintain their telomeres during their second year in the stream. However, body size at the start of the experiment, reflecting growth rate during their first year of life, was negatively correlated with change in telomere length over the following year. This result raises the possibility that rapid growth early in life induces delayed costs in cellular maintenance.

Renal function in hepatosplenic schistosomiasis--an assessment of renal tubular disorders.

BackgroundRenal involvement in Schistosoma mansoni infection is not well studied. The aim of this study is to investigate the occurrence of renal abnormalities in patients with hepatosplenic schistosomiasis (HSS), especially renal tubular disorders.MethodsThis is a cross-sectional study with 20 consecutive patients with HSS followed in a medical center in Maceió, Alagoas, Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl2) after a 12-h period of water and food deprivation. The biomarker monocyte chemoattractant protein 1 (MCP-1) was quantified in urine. Fractional excretion of sodium (FENa+), transtubular potassium gradient (TTKG) and solute-free water reabsorption (TcH2O) were calculated. The HSS group was compared to a group of 17 healthy volunteers.ResultsPatients' mean age and gender were similar to controls. Urinary acidification deficit was found in 45% of HSS patients. Urinary osmolality was significantly lower in HSS patients (588±112 vs. 764±165 mOsm/kg, p = 0,001) after a 12-h period of water deprivation. TcH2O was lower in HSS patients (0.72±0.5 vs. 1.1±0.3, p = 0.04). Urinary concentration deficit was found in 85% of HSS patients. The values of MCP-1 were higher in HSS group than in control group (122±134 vs. 40±28 pg/mg-Cr, p = 0.01) and positively correlated with the values of microalbuminuria and proteinuria.ConclusionsHSS is associated with important kidney dysfunction. The main abnormalities found were urinary concentrating ability and incomplete distal acidification defect, demonstrating the occurrence of tubular dysfunction. There was also an increase in urinary MCP-1, which appears to be a more sensitive marker of renal damage than urinary albumin excretion rate.

Short-term food deprivation increases amplitudes of heartbeat-evoked potentials.

Nutritional state (i.e., fasting or nonfasting) may affect the processing of interoceptive signals, but mechanisms underlying this effect remain unclear. We investigated 16 healthy women on two separate days: when satiated (standardized food intake) and after an 18-h food deprivation period. On both days, heartbeat-evoked potentials (HEPs) and cardiac and autonomic nervous system activation indices (heart rate, normalized low frequency heart rate variability [nLF HRV]) were assessed. The HEP is an EEG pattern that is considered an index of cortical representation of afferent cardiovascular signals. Average HEP activity (R wave +455-595 ms) was enhanced during food deprivation compared to normal food intake. Cardiac activation did not differ between nutritional conditions. Our results indicate that short-term food deprivation amplifies an electrophysiological correlate of the cortical representation of visceral-afferent signals originating from the cardiovascular system. This effect could not be attributed to increased cardiac activation, as estimated by heart rate and nLF HRV, after food deprivation.

GH, IGF-I and GH receptors mRNA expression in response to growth impairment following a food deprivation period in individually housed cichlid fish Cichlasoma dimerus.

Cichlasoma dimerus is a social cichlid fish capable of growing at high rates under laboratory conditions, but knowledge on somatic growth regulation is still unclear. Growth hormone (GH)/insulin-like growth factor I (IGF-I) axis is the key regulator of somatic growth in vertebrates. Two types of growth hormone receptors have been described in teleost fish, named GH receptor type 1 (GHR1) and type 2 (GHR2). In addition, isoforms of these receptors lacking part of the intracellular region have been described. The aim of this study was to evaluate the somatic growth, liver histology and changes in the GH/IGF-I axis after 4 weeks of food deprivation in C. dimerus. Four-week fasted fish showed reductions in specific growth rates in body weight (p < 0.001) and standard length (p < 0.001). Additionally, the hepatosomatic index (p < 0.001) and hepatocyte area (p < 0.001) decreased in fasted fish, while no changes in glucose levels were detected in plasma. The starvation protocol failed to induce changes in GH mRNA levels in the pituitary and IGF-I mRNA levels in liver. In contrast, IGF-I mRNA levels in muscle decreased in fasted fish (p = 0.002). On the other hand, GHR2 (detected with primer sets designed over the extracellular and intracellular region) was upregulated by starvation both in liver and muscle (p < 0.05), while GHR1 remained unchanged. These results show that a fasting period reduced somatic growth both in length and body weight concomitantly with alterations on liver and muscle GHR2 and muscle IGF-I mRNA expression.

An increase in insulin is important for the acquisition conditioned taste aversion in Lymnaea

Conditioned taste aversion (CTA) in Lymnaea is brought about by pairing a sucrose solution (the conditioned stimulus, CS) with an electric shock (the unconditioned stimulus, US). Following repeated CS–US pairings, CTA occurs and it is consolidated into long-term memory (LTM). The best CTA is achieved, if snails are food-deprived for 1day before training commences. With a longer period of food deprivation (5days), learning and memory formation does not occur. It has been hypothesized that the levels of insulin in the central nervous system (CNS) are very important for CTA to occur. To test his hypothesis, we injected insulin directly into 5-day food-deprived snails. The injection of insulin, as expected, resulted in a decrease in hemolymph glucose concentration. Consistent with our hypothesis with insulin injection, learning and memory formation of CTA occurred. That is, the ‘insulin spike’ is more important than an increase in hemolymph glucose concentration for CTA-LTM. If we injected an insulin receptor antibody into the snails before the insulin injection, learning was formed but memory formation was not, which is consistent with our previous study. Therefore, a rise in the insulin concentration (i.e., insulin spike) in the CNS is considered to be a key determining factor in the process of CTA-LTM.

Effect of Food Deprivation Period on the Development and Reproduction of Riptortus pedestris (Hemiptera: Alydidae), and Its Egg Parasitism.

The bean bug, Riptortus pedestris (F.) (Hemiptera: Alydidae) is one of the most important pests of soybean (Glycine max L. Merrill) in Korea and Japan. R. pedestris is known to appear early in spring when leguminous seeds such as soybean are not available. Because soybean has been reported to be the most important food source for R. pedestris development, in this study, we assessed the effect of this period of soybean deprivation during the nymphal stage on the development and reproduction of R. pedestris and on egg parasitism by its two egg parasitoids. More than 50% of the R. pedestris population tested survived on barley, even when they did not start feeding on soybean until the fourth instar. Nevertheless, R. pedestris nymphs deprived of soybean developed more slowly and became smaller adults than those provided with soybean. However, no difference was observed in the preovipositional period or fecundity between these groups. In addition, neither the hatch nor the egg parasitism rate by two egg parasitoids was affected by the presence or absence of soybeans in the nymphal diet. This study indicates that R. pedestris nymphs can develop successfully even when lacking this important food source in early life, and that adult reproduction is not affected by the quality of diet ingested during the nymphal period.

Effects of short-term starvation and re-feeding on antioxidant defense status in Mesopotamichthys sharpeyi (Günther, 1874) fingerlings

The objective of this study was to evaluate the impact of short-term starvation and re-feeding on oxidative stress in Mesopotamichthys sharpeyi (Gunther, 1874). After two weeks adaptation to new conditions, a total number of 270 fingerlings were distributed into nine 300-L fiberglass tanks, equipped with aeration system in three treatments including 4, 8 and 16 days starvation (each in 3 replicates). After starvation, all groups were fed for 32 days. At the beginning of trial and at the end of starvation and re-feeding periods, blood samples were collected, plasma was separated and activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) and malondialdehyde (MDA) content were assayed. Based on the results, no significant difference was observed in SOD activity at the end of starvation and also after re-feeding between the different treatments. At the end of starvation the activity of the CAT and GPX increased significantly in 8 and 16 days of starvation groups compared to the base. Moreover, a significant increase in MDA levels of plasma was found during food deprivation. These findings showed that short-time starvation increased antioxidant enzymes activity in plasma of M. sharpeyi but short-term food deprivation and re-feeding periods in this species does not cause disturbances in the antioxidant defense status.

Effects of variation in nutrition on male morph development in the bulb mite Rhizoglyphus robini.

In male dimorphic species, growth influences morph expression and thereby the reproductive success of males. However, how variation in nutritional conditions affects male morph development and whether males can compensate for lost growth is poorly known. Here, we performed an experiment where males of the bulb mite (Rhizoglyphus robini)-which are fighters, able to kill other mites, or benign scramblers-were offered high quality food during the larval stage, but food of high or low quality during the protonymph and tritonymph (=final) stage. When food quality was low during the latter two stages, males matured smaller, later and were more likely to be a scrambler than when food quality was high. We found no evidence for compensatory growth: when males had low quality food only during the protonymph stage, they matured at the same age, but grew at a slower rate and matured at a smaller size than males that had high quality food throughout ontogeny. Furthermore, males that experienced this transient period of low food quality were less likely to mature as a fighter. Interestingly, scrambler increase in body size during the protonymph and tritonymph stages was always lower than that of fighters. Given the strong link between adult size and fitness, combined with the different development times and life histories of the male morphs, the lack of ability to compensate for a transient period of food deprivation during ontogeny is likely to have consequences for the dynamics of bulb mite populations.

ICR 마우스를 대상으로 대두 가수분해물 분획물의 식욕 억제 및 Ghrelin 분비에 대한 연구

The objective of this study was to investigate the effects of soy hydrolysate fractions on appetite suppression and ghrelin releasing. In a short-term experiment, the cumulative food intake and serum ghrelin level were decreased significantly (p<0.05) during a 4-hr period after the interperitoneal injection of soy hydrolysate fractions (0.5, 1 g/kg BW), following a 12-hr period of food deprivation. In a long-term experiment, food efficiency ratio (FER) was also reduced significantly (p<0.05), when soy hydrolysate fractions (0.5, 1% in drinking water) were given orally for 8 wks. Therefore, we found that soy hydrolysate fractions affected food intake through appetite and ghrelin releasing in short-term and long-term experiments. In conclusion, this study indicated that soy hydrolysate fractions would diminish the sensation of hunger by reducing the secretion of orexigenic factors such as ghrelin that send satiety signals to the brain, terminating food intake.

Can Physical Exercise or Food Deprivation Cause Release of Fat‐Stored Cannabinoids?

The aim of this study was to evaluate whether physical exercise or food deprivation may increase cannabinoid levels in serum or urine in abstinent chronic cannabis users. The study took place in a drug detoxification ward parallel to study participants receiving treatment. Six chronic, daily cannabis users (one female, five males, average age 30.0 years; BMI 20.8) were exposed to a 45-min. moderate-intensity workout and a 24-hr period of food deprivation. Serum samples were drawn prior to and after interventions and analysed for Δ9-tetrahydrocannabinol (THC) and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) by liquid chromatography–tandem mass spectrometry (LCMSMS), and all voided urine was tested for THCCOOH by LCMSMS and normalized to the creatinine levels, yielding ng/mg ratios. There were no major differences in the measured cannabinoid levels in serum or urine before and after physical exercise or food deprivation. We conclude that exercise and/or food deprivation are unlikely to cause sufficient cannabinoid concentration changes to hamper correct interpretations in drug testing programmes.

Neuropeptide Y1 receptor is a key element in stress response to food deprivation (1126.7)

The hypothalamic‐pituitary adrenal (HPA) axis functions as a default pathway for the maintenance of energy homeostasis. Food restriction or deprivation leads to prolonged HPA axis activation but the exact mechanism of this continuous HPA activation is not yet well understood. Our experiments were designed to determine whether neuropeptide Y (NPY) Y1 receptors participate in the stress response to food deprivation since NPY expression is elevated during periods of fasting. Food deprivation of male rats for 24 hours caused weight loss, adrenal gland hypertrophy and increased plasma ACTH and corticosterone concentrations. Food deprivation increased NPY mRNA expression in arcuate and brainstem C2/A2 nuclei areas that are known to project to the hypothalamic paraventricular nucleus (PVN). While the total area of CRH mRNA positive cells in the PVN decreased during food deprivation, the CRH mRNA signal intensity increased in the remaining active cells. Food deprivation also increased pCREB‐ir expression in PVN, an indication for neuronal activation. A majority of pCREB‐positive cells were CRH/Y1‐ir neurons. Infusion into the PVN of 1 nmol BIBP3226, a specific Y1 receptor antagonist, eliminated the elevated corticosterone blood levels in food‐deprived animals. Our observations support the notion that hypothalamic NPY Y1 receptors expressed by CRH neurons are pivotal for triggering a strong stress response during periods of food deprivation.Grant Funding Source: Supported by NIMH 62621

Characterization of the endocrine, digestive and morphological adjustments of the intestine in response to food deprivation and torpor in cunner, Tautogolabrus adspersus

The cunner, Tautogolabrus adspersus, is a marine teleost endemic to the cold waters of the Northwest Atlantic Ocean. The cunner is non-migratory and is known for its remarkable ability to endure the freezing winter months with little to no food by entering a torpid/dormant state. To evaluate the physiological strategies employed by the cunner's intestinal tract to withstand food deprivation, fish were sampled for their gut after a four-week period of acute food deprivation during their summer (active/feeding) state, as well as after 4months of overwinter fasting. Digestive capacity was evaluated by measuring digestive enzyme activity and related mRNA transcript expression for trypsin, alkaline phosphatase, alanine aminopeptidase and lipase. In order to assess how gut hormones affect/are affected by acute fasting and torpor, we examined the intestinal mRNA expression of several putative appetite regulators, i.e. CCK, apelin, orexin and mTOR. Short-term summer fasting induced a reduction in the activity, but not the transcript expression, of all digestive enzymes examined as well as a reduction in gut apelin mRNA. Torpor induced a reduction in the activity of all enzymes with the exception of alanine aminopeptidase, and a decrease in mRNA levels of alanine aminopeptidase, orexin, CCK and mTOR. Our results suggest that both acute fasting and long-term fasting induce a reduction in the intestinal function of cunner, as evidenced by an overall decrease in the activities of digestive enzymes and mRNA expression of several factors involved in feeding and digestion.