Circadian Feeding Research Articles

Disrupted circadian rhythmicity of the intestinal glucose transporter SGLT1 in Zucker diabetic fatty rats.

Intestinal absorptive capacity shows a circadian rhythm synchronized with eating patterns. Disrupting these coordinated rhythms, e.g., with shift work, may contribute to metabolic disease. Circadian expression of nutrient transporters has not been studied in metabolic disease. We studied the circadian rhythm of intestinal transporter sodium glucose co-transporter type 1 (SGLT1) in an obese diabetic rat. We compared obese Zucker diabetic fatty (ZDF) rats to lean ZDF littermates. Temporal feeding patterns were assessed, then rats were harvested at Zeitgeber (ZT, ZT0 = 7:00 a.m.) 3, 9, or 15 to measure insulin resistance, SGLT1 expression and intestinal glucose absorption capacity. Regulators of SGLT1 (sweet taste receptor T1R2/3; clock genes) were measured to elucidate underlying mechanisms. Both groups exhibited altered circadian food intake. Obese ZDF rats lost circadian rhythmicity of SGLT1 mRNA expression and functional activity. Lean ZDF rats maintained rhythmicity of SGLT1 mRNA expression but that of functional glucose absorption was blunted. Circadian rhythms of intestinal clock genes were maintained in both groups. Neither group had discernible rhythms of intestinal GLUT2 (glucose transporter) or T1R2 (sweet taste receptor component) mRNA expression. In summary, lean and obese ZDF rats exhibited similar disruptions in circadian feeding. Glucose intolerance was evident in lean rats, but only obese rats further developed diabetes and exhibited disrupted circadian rhythmicity of both SGLT1 mRNA expression and function. Our findings suggest that disrupted circadian feeding rhythms contribute to glucose intolerance, but additional factors (genetics, changes in nutrient sensing/transport) are needed to lead to full diabetes.

Differential regulation of feeding rhythms through a multiple‐photoreceptor system in an avian model of blindness

All organisms have evolved photodetection systems to synchronize their physiology and behavior with the external light-dark (LD) cycles. In nonmammalian vertebrates, the retina, the pineal organ, and the deep brain can be photoreceptive. Inner retinal photoreceptors transmit photic information to the brain and regulate diverse nonvisual tasks. We previously reported that even after preventing extraretinal photoreception, blind GUCY1* chickens lacking functional visual photoreceptors could perceive light that modulates physiology and behavior. Here we investigated the contribution of different photoreceptive system components (retinal/pineal and deep brain photoreceptors) to the photic entrainment of feeding rhythms. Wild-type (WT) and GUCY1* birds with head occlusion to avoid extraocular light detection synchronized their feeding rhythms to a LD cycle with light >12 lux, whereas at lower intensities blind birds free-ran with a period of >24 h. When released to constant light, both WT and blind chickens became arrhythmic; however, after head occlusion, GUCY1* birds free-ran with a 24.5-h period. In enucleated birds, brain illumination synchronized feeding rhythms, but in pinealectomized birds only responses to high-intensity light (≥800 lux) were observed, revealing functional deep brain photoreceptors. In chickens, a multiple photoreceptive system, including retinal and extraretinal photoreceptors, differentially contributes to the synchronization of circadian feeding behavior.

Paraventricular NUCB2/nesfatin-1 rises in synchrony with feeding suppression during early light phase in rats

Obesity often results from hyperphagia and involves rhythm disorder. Circadian feeding pattern is suggested to be implicated in energy homeostasis while its disorder in obesity. However, the mechanism underlying circadian feeding is little known. PVN is considered a regulatory center for feeding and circadian activities of hormone release and autonomic nerve. Nucleobindin2 (NUCB2) and its processing product nesfatin-1 (NUCB2/nesfatin-1) are localized in the hypothalamic paraventricular nucleus (PVN) and implicated in regulation of feeding. This study aimed to clarify whether the PVN NUCB2/nesfatin-1 expression exhibits diurnal rhythm and, if so, whether it is related to circadian feeding. Here we show that NUCB2 mRNA expression in the PVN rises during early light phase (LP) in parallel with suppression of food intake. Immunoneutralization of PVN NUCB2/nesfatin-1 with anti-nesfatin-1 IgG during LP, but not dark phase, increased food intake. PVN-selective shRNA-induced knockdown of NUCB2 mRNA expression elevated food intake. Furthermore, the rise of PVN NUCB2 mRNA during LP was blunted in Zucker-fatty obese rats which exhibited LP-preferential hyperphagia. The increases in food intake during LP and 24h were significantly corrected by intracerebroventricular injection of nesfatin-1 during LP. These results reveal the diurnal rhythm of PVN NUCB2 mRNA expression characterized by early LP rise, which may serve as a factor to limit LP food intake, contributing to circadian feeding. Furthermore, impaired NUCB2/nesfatin-1 rhythm may be related to dysregulated feeding pattern and hyperphagia in Zucker-fatty rats.

Characterization of neuropeptide Y in snakeskin gourami and the change in its expression due to feeding status and melanocortin 4 receptor expression

In this study, we characterized the neuropeptide Y (NPY) mRNA in snakeskin gourami (Trichogaster pectoralis) (TpNPY). TpNPY displayed characteristics typical of previously reported NPYs, and it exhibited a high degree of homology with the NPY proteins of other vertebrates. A phylogenetic analysis demonstrated that TpNPY was closely related to the NPYs found in the acanthomorpha and salmoniformes fish species. TpNPY was found to be ubiquitously expressed in all brain regions when assessed by real-time RT-PCR and in situ hybridization. In addition, a graded expression level of TpNPY was observed in peripheral tissues; for example, a moderate level of TpNPY was found in the gills, liver, kidney, stomach, intestine, spleen and gonads, while a low level of TpNPY was found in the muscle. The change in expression of TpNPY with respect to daily feeding habits was investigated in distinct brain regions, including the telencephalon, mesencephalon, metencephalon, and diencephalon. Fluctuations in the expression level of TpNPY were observed for a 24h post-prandial period. Except for the telencephalon, a reduction in TpNPY expression was found after a meal, while a peak level of TpNPY was observed 1h before the scheduled breakfast. Furthermore, there was a positive correlation between TpNPY and TpMC4R in the telencephalon and diencephalon throughout the circadian feeding cycle, which suggests that there is a connection between the function of NPY and the melanocortin system for the regulation of daily feeding. Fish brains were incubated with an MC4R antagonist (i.e., HS024), and the expression of TpNPY and TpMC4R was measured. Interestingly, there was a significant relationship between the expression of TpNPY and TpMC4R under the effects of HS024, which demonstrates that there are interactions between MC4R and NPY, particularly in a hyperphagic state.

Shift of Circadian Feeding Pattern by High-Fat Diets Is Coincident with Reward Deficits in Obese Mice

Recent studies provide evidence that high-fat diets (HF) trigger both i) a deficit of reward responses linked to a decrease of mesolimbic dopaminergic activity, and ii) a disorganization of circadian feeding behavior that switch from a structured meal-based schedule to a continuous snacking, even during periods normally devoted to rest. This feeding pattern has been shown to be a cause of HF-induced overweight and obesity. Our hypothesis deals with the eventual link between the rewarding properties of food and the circadian distribution of meals. We have investigated the effect of circadian feeding pattern on reward circuits by means of the conditioned-place preference (CPP) paradigm and we have characterized the rewarding properties of natural (food) and artificial (cocaine) reinforcers both in free-feeding ad libitum HF mice and in HF animals submitted to a re-organized feeding schedule based on the standard feeding behavior displayed by mice feeding normal chow (“forced synchronization”). We demonstrate that i) ad libitum HF diet attenuates cocaine and food reward in the CPP protocol, and ii) forced synchronization of feeding prevents this reward deficit. Our study provides further evidence that the rewarding impact of food with low palatability is diminished in mice exposed to a high-fat diet and strongly suggest that the decreased sensitivity to chow as a positive reinforcer triggers a disorganized feeding pattern which might account for metabolic disorders leading to obesity.

Leptin-sensitive neurons in the arcuate nuclei contribute to endogenous feeding rhythms

Neural sites that interact with the suprachiasmatic nuclei (SCN) to generate rhythms of unrestricted feeding remain unknown. We used the targeted toxin, leptin conjugated to saporin (Lep-SAP), to examine the importance of leptin receptor-B (LepR-B)-expressing neurons in the arcuate nucleus (Arc) for generation of circadian feeding rhythms. Rats given Arc Lep-SAP injections were initially hyperphagic and rapidly became obese (the "dynamic phase" of weight gain). During this phase, Lep-SAP rats were arrhythmic under 12:12-h light-dark (LD) conditions, consuming 59% of their total daily intake during the daytime, compared with 36% in blank-SAP (B-SAP) controls. Lep-SAP rats were also arrhythmic in continuous dark (DD), while significant circadian feeding rhythms were detected in all B-SAP controls. Approximately 8 wk after injection, Lep-SAP rats remained obese but transitioned into a "static phase" of weight gain marked by attenuation of their hyperphagia and rate of weight gain. In this phase, Arc Lep-SAP rats exhibited circadian feeding rhythms under LD conditions, but were arrhythmic in continuous light (LL) and DD. Lep-SAP injections into the ventromedial hypothalamic nucleus did not cause hyperphagia, obesity, or arrhythmic feeding in either LD or DD. Electrolytic lesion of the SCN produced feeding arrhythmia in DD but not hyperphagia or obesity. Results suggest that both Arc Lep-SAP neurons and SCN are required for generation of feeding rhythms entrained to photic cues, while also revealing an essential role for the Arc in maintaining circadian rhythms of ad libitum feeding independent of light entrainment.

Circadian Feeding Drive of Metabolic Activity in Adipose Tissue and not Hyperphagia Triggers Overweight in Mice: Is There a Role of the Pentose-Phosphate Pathway?

High-fat (HF) diets trigger an increase in adipose tissue and body weight (BW) and disordered eating behavior. Our study deals with the hypothesis that circadian distribution of energy intake is more relevant for BW dynamics than diet composition. Four-week-old mice were exposed for 8 wk to a HF diet and compared with animals receiving control chow. HF mice progressively increased BW, decreased the amount of nocturnal (1800-0900 h) calories (energy or food intake) (30%) and increased diurnal (0900-1800 h) caloric intake (energy or food intake), although total daily intake was identical between groups. Animals were killed at 3-h intervals and plasma insulin, leptin, corticosterone, glucose, and fatty acid levels quantified. Adipose tissue was weighed, and enzymatic activities integral to the pentose phosphate pathway (PPP) assayed in lumbar adipose tissue. Phosphorylated AMP-dependent protein kinase and fatty acid synthase were quantified by Western blotting. In HF mice, there was a shift in the circadian oscillations of plasma parameters together with an inhibition of PPP activity and a decrease in phosphorylated AMP-dependent protein kinase and fatty acid synthase. In a second experiment, HF mice were forced to adhere to a circadian pattern of food intake similar to that in control animals. In this case, BW, adipose tissue, morning plasma parameters and PPP activity appeared to be normal. These data indicate that disordered feeding behavior can trigger BW gain independently of food composition and daily energy intake. Because PPP is the main source of reduced nicotinamide adenine dinucleotide phosphate, we suggest that PPP inhibition might be an early marker of adipose dysfunction in diet-induced obesity.

Circadian differences between two rat strains in their feeding and drinking micro- and macrostructures

Basal divergences in circadian feeding and drinking patterns among different rat strains may bias comparative physiological and pharmacological studies. To examine this issue in detail, Long-Evans (Turku/AB) (L-E) and Han/Wistar (Kuopio) (H/W) rats were monitored with an automated system for seven consecutive days after a habituation period. For the analysis, days were split into hours or into four diurnal periods, and the chronologically repetitive nature of the data was taken into account. While L-E rats displayed two distinct peaks in feeding and drinking that coincided with the light shifts, H/W rats exhibited their lowest consummatory activity at the morning light shift. Further differences were recorded in a number of variables including numbers of meals and drinking episodes as well as their durations. These findings reveal surprisingly wide inter-strain differences. Hence, one should be careful in generalizing ingestive behavioural data obtained from a single rat strain to the entire species.

Circadian integration of sleep-wake and feeding requires NPY receptor-expressing neurons in the mediobasal hypothalamus

Sleep and feeding rhythms are highly coordinated across the circadian cycle, but the brain sites responsible for this coordination are unknown. We examined the role of neuropeptide Y (NPY) receptor-expressing neurons in the mediobasal hypothalamus (MBH) in this process by injecting the targeted toxin, NPY-saporin (NPY-SAP), into the arcuate nucleus (Arc). NPY-SAP-lesioned rats were initially hyperphagic, became obese, exhibited sustained disruption of circadian feeding patterns, and had abnormal circadian distribution of sleep-wake patterns. Total amounts of rapid eye movement sleep (REMS) and non-REMS (NREMS) were not altered by NPY-SAP lesions, but a peak amount of REMS was permanently displaced to the dark period, and circadian variation in NREMS was eliminated. The phase reversal of REMS to the dark period by the lesion suggests that REMS timing is independently linked to the function of MBH NPY receptor-expressing neurons and is not dependent on NREMS pattern, which was altered but not phase reversed by the lesion. Sleep-wake patterns were altered in controls by restricting feeding to the light period, but were not altered in NPY-SAP rats by restricting feeding to either the light or dark period, indicating that disturbed sleep-wake patterns in lesioned rats were not secondary to changes in food intake. Sleep abnormalities persisted even after hyperphagia abated during the static phase of the lesion. Results suggest that the MBH is required for the essential task of integrating sleep-wake and feeding rhythms, a function that allows animals to accommodate changeable patterns of food availability. NPY receptor-expressing neurons are key components of this integrative function.

Examining the daily feeding rhythms of amago Oncorhynchus masou masou using self-feeding systems

Knowledge of circadian feeding rhythms in farmed fish species can help farmers determine the optimal feeding times to maximise feed consumption and minimise feed wastage. This study examined i) the circadian feeding rhythms, ii) the inter-day variability in feed demanded and iii) feed wastage of amago, Oncorhynchus masou masou, fed using self-feeding systems. Three replicate groups of 16 fish were held under a 12:12 light:dark cycle at 16 °C for 56 days. After a 28-day self-feeder acclimation period all three groups had become competent self-feeders and the treatment period ran from day 28 to day 56. Under the experimental light and temperature regime utilised amago appear to be visual self-feeders, actuating self-feeders almost exclusively during the light phase (99.9% of actuations). All three groups exhibited a distinct diurnal feeding rhythm within the light phase and demonstrated significant ( P < 0.05) crepuscular peaks in feed demand. In addition, one group also displayed a significant peak at midday. Daily ration varied both within and between groups but no clear rhythmicity was observed in these variations. Feed waste was very low (always < 2%) for each group. The results of this study suggest that farmers can optimise daily feed consumption by feeding amago exclusively during the light phase, specifically at dawn and dusk, with a possible extra meal at midday.

Characterization of melanocortin 4 receptor in Snakeskin Gourami and its expression in relation to daily feed intake and short-term fasting

In this study, melanocortin 4 receptor ( MC4R) was characterized in Snakeskin Gourami ( Trichogaster pectoralis) and designated as TpMC4R. The TpMC4R contained predicted regions that were structural features of MC4R subtypes of vertebrates. In addition, phylogenetic analyses showed that TpMC4R were in MC4R orthologues and closely related to piscine MC4Rs. The TpMC4R transcripts were detected in embryos at all developmental stages. Further, its mRNA was detectable in unfertilized eggs, suggesting that TpMC4R could be classified as maternal mRNA. Using real-time RT-PCR, graded expression at each central and peripheral tissue was demonstrated. Localization of TpMC4R expression in the brain was performed by in situ hybridization. An experiment was conducted to determine the expression profile of TpMC4R during daily feeding in each region of the brain. Fish were fed twice a day at 10:00 and 16:00, and the level of TpMC4R expression was analyzed at 9:00, 11:00, 13:00 and 15:00. The expression level of TpMC4R was significantly reduced at 15:00 compared to that at all previous times (9:00, 11:00 and 13:00). Moreover, significantly higher expression levels of TpMC4R were observed at 18- and 24-h fasting periods. The finding of variation in MC4R expression level during daily feeding and fasting period revealed some direct and/or indirect relations of the MC4R expression to circadian feeding rhythm and short-term food deprivation in fish.

Disruption of Circadian Feeding Patterns in Obese ZDF Rats

Disruption of Circadian Feeding Patterns in Obese ZDF Rats

High-salt diet advances molecular circadian rhythms in mouse peripheral tissues

Dietary compounds influence the expression of various genes and play a major role in changing physiological and metabolic states. However, little is known about the role of food ingredients in the regulation of circadian gene expression. Here, we show that feeding mice with a high-salt (HS) diet ad libitum for over 2 weeks advanced the phase of clock gene expression by about 3 h in the liver, kidney, and lung, but did not change circadian feeding, drinking, and locomotor rhythms. Focused DNA microarray analysis showed that the expression phase of many genes related to metabolism in the liver was also advanced. Immediately before phase advancement in peripheral tissues, the mRNA expression of sodium–glucose cotransporter 1 ( Sglt1) and glucose transporter 2 ( Glut2), that are responsible for glucose absorption, was increased in the jejunum. Furthermore, blood glucose uptake increased more rapidly after consuming the HS diet than the control diet. Moreover, phloridzin, a specific inhibitor of SGLT1, prevented the increased glucose transporter expression in the jejunum and phase advancement in the livers of mice on the HS diet. These results suggest that increased glucose absorption induced by dietary HS alters the food entrainment of peripheral molecular circadian rhythms.

Neurohormonal regulation of feed intake and response to nutrients in fish: aspects of feeding rhythm and stress

The regulation of feed intake is very complex and involves interaction among the circadian and homeostatic control systems within the central nervous system, the gastrointestinal tract and the environment. The hypothalamus, which receives, integrates and transmits relevant internal and external signals, is recognized as the primary centre of regulation of feed intake. The neuroendocrine factors that originate from the hypothalamus either stimulate or inhibit feed intake so that nutritional demands of the organism can be ful¢lled and energy balance can be achieved. Appetite regulation is a physiological mechanism in which a variety of neurohormones interact and ¢sh show diierent feeding behaviour (e.g. diurnal, nocturnal). This complicated system is very sensitive to any disturbance. Fish in farms and ¢sh in a natural environment are equipped with the same combination of neurohormones to regulate feed intake, but they meet diierent challenges, particularly with regard to the type of feed and feeding schedule. In this review, the neurohormonal regulation of feed intake is analysed in ¢sh in terms of entrainment of their circadian feeding rhythms and while exposed to diierent stressors in captivity.

Síndrome do comer noturno: aspectos conceituais, epidemiológicos, diagnósticos e terapêuticos

O comportamento e o padrão alimentar são complexos, envolvendo aspectos metabólicos, fisiológicos e ambientais, e apresentando ritmicidade circadiana, herdada e espécie específica, sendo a humana essencialmente diurna. Este estudo tem como objetivo descrever a Síndrome do Comer Noturno, caracterizada por um atraso circadiano do padrão alimentar, mediado por alterações neuroendócrinas ao estresse. Procedeu-se à revisão da bibliografia existente, a partir do exame de artigos publicados pela literatura internacional nas bases de dados dos sites Pubmed, Lilacs, Sirus, referentes ao período de 1955 até as últimas publicações em 2007. Realizou-se um levantamento bibliográfico usando os seguintes descritores: night eating syndrome, sleep, circadian rhythm, appetite, nocturnal eating. Foram localizados 74 artigos e destes foram selecionados 26, cujo tema central era a Síndrome do Comer Noturno. Apesar dos estudos realizados, ainda existe longo percurso a ser percorrido para compreender a gênese da Síndrome do Comer Noturno e as relações intrínsecas desta com outros processos fisiopatogênicos. Tendo em conta que esta síndrome está vinculada ao controle da fome e da saciedade e à dessincronização entre o ritmo alimentar e o ritmo sono/vigília, a compreensão do seu processo gênico poderá demonstrar o impacto da dessincronização dos ritmos circadianos da alimentação no processo saúde-doença, e auxiliar a compreensão de fatores implicados no índice crescente de obesidade da sociedade moderna.

Maize silage particle length modulates feeding patterns and milk composition in loose-housed lactating Holstein cows

This study analysed feeding patterns and feed selective consumption by loose-housed lactating dairy cows fed diets based on maize silage (MS) with different particle length (PL) to establish its effects on overall dry matter intake (DMI) and productive performance. Twelve multiparous Holstein cows were offered a total mixed ration (TMR) with three different PL of MS at harvesting (i.e., long, medium, and short). Results demonstrated greater numbers of day-time meals (i.e., 07:30–19:00 h) when PL was decreased from long to medium ( P < 0.05). Night-time (i.e., 19:00–06:30 h) changes in the feeding pattern included an increased amount of feed per meal ( P < 0.05) and a tendency to increase eating time per meal ( P < 0.10) in cows fed the short-PL diet. Lowering the PL of MS also lowered the selective consumption against physically effective fibre larger than 1.18 mm (peNDF > 1.18 ; P < 0.05) and in favour of fine particles (i.e., particles passing through 1.18 mm screen; P < 0.01). Decreasing PL of MS from long to medium and short increased daily DMI as well as the intake of energy and other nutrients contained in the diet including the amount of peNDF > 1.18 ( P < 0.01). The decrease in the PL of the diet also was associated with increased milk protein and lactose yield and milk urea nitrogen ( P < 0.05). The actual milk yield and fat-corrected milk were not affected by the diet ( P > 0.10). Although lowering of the PL tended to increase daily milk energy output ( P < 0.10), the ratio between energy milk output and the energy intake was linearly decreased ( P < 0.01), indicating a lower milk efficiency for the lower-PL diets. In conclusion, particle length of MS in a TMR has the potential to modulate circadian feeding patterns, selective consumption of the feed, daily DMI, and milk composition in high-producing dairy cows.

Feeding ecology and predation impact of the recently established amphipod, Themisto libellula, in the St. Lawrence marine system, Canada

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 373:53-70 (2008) - DOI: https://doi.org/10.3354/meps07716 Feeding ecology and predation impact of the recently established amphipod, Themisto libellula, in the St. Lawrence marine system, Canada Alexandra Marion1,2, Michel Harvey2,*, Denis Chabot3, Jean-Claude Brêthes1 1Institut des Sciences de la Mer (ISMER), Université du Québec à Rimouski (UQAR), 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada 2Direction des Sciences Océaniques et Environnementales, Ministère des Pêches et des Océans, Institut Maurice-Lamontagne, CP 1000, Mont-Joli, Québec G5H 3Z4, Canada 3Direction des Sciences Halieutique et de l’Aquaculture, Ministère des Pêches et des Océans, Institut Maurice-Lamontagne, CP 1000, Mont-Joli, Québec G5H 3Z4, Canada *Corresponding author. Email: Michel.Harvey@dfo-mpo.gc.ca ABSTRACT: Themisto libellula was virtually absent from the St. Lawrence marine system (SLMS) before 1990. Since then, it has become an abundant, full-time resident of this system. Hyperiid amphipods of the genus Themisto are principally carnivorous and represent an essential link in the trophic pathway from secondary production to higher trophic levels. Sampling of T. libellula was carried out in the lower St. Lawrence Estuary (LSLE) and the northwest Gulf of St. Lawrence (NWGSL) in the fall of 1998, 2003 and 2004 to study the feeding dynamics and predation impact of this species on mesozooplankton and macrozooplankton communities. Our results showed that T. libellula was an opportunistic predator with a circadian feeding cycle; activity was higher during the second part of the night and the sunrise period. Stomach content analyses showed that these amphipods consumed chiefly copepods, in particular, the copepodite stages CIV and CV of Calanus finmarchicus. Euphausiids, chaetognaths, amphipods and mysids constituted other important prey. Digestion time was estimated at 13 h. The daily ingestion rate of T. libellula was estimated using 2 approaches: (1) stomach fullness index and (2) mean number of prey removed per unit of time and converted to prey biomass using the stage-species dry masses of each prey item. We found that the daily ingestion rate of T. libellula ranged from 6.32 to 16.82% of body dry mass per day in both study areas (LSLE and NWGSL). Concerning predation impact, T. libellula consumed between 0.14 and 1.79% of the combined mesozooplankton and macrozooplankton standing stock per day and between 0.43 and 2.48% of the C. finmarchicus standing stock. Themisto libellula may thus exert a significant control on the mesozooplankton and macrozooplankton communities in the SLMS through direct predation. KEY WORDS: Hyperiid amphipod · Themisto libellula · Feeding ecology · Ingestion rate · Digestion time · Predation impact · Gulf of St. Lawrence Full text in pdf format PreviousNextCite this article as: Marion A, Harvey M, Chabot D, Brêthes JC (2008) Feeding ecology and predation impact of the recently established amphipod, Themisto libellula, in the St. Lawrence marine system, Canada. Mar Ecol Prog Ser 373:53-70. https://doi.org/10.3354/meps07716Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 373. Online publication date: December 23, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.

7.1. Circadian clocks, feeding and metabolism

7.1. Circadian clocks, feeding and metabolism

A study of circadian eating and sleeping patterns in night eating syndrome (NES) points the way to future studies on NES and sleep-related eating disorder

1389-9457/$ see front matter 2006 Published by Elsevier B.V. doi:10.1016/j.sleep.2006.06.001 q Article reviewed: O’Reardon JP, Ringel BL, Dinges DF, Allison KC, Rogers NL, Martino NS, Stunkard AJ. Circadian eating and sleeping patterns in the night eating syndrome. Obes Res 2004;12:1789–1796. * Tel.: +1 612 873 6201; fax: +1 612 904 4207. E-mail address: schen010@umn.edu energy intake differed greatly. The temporal pattern of food intake of night eaters was delayed compared to controls. Food intake after the evening meal, as a proportion of the 24-h intake, was more than threefold greater in NES subjects compared to controls (34.6 ± 10.1% vs. 10.0 ± 6.9%, p = 0.001). NES subjects had sleep onset, offset, and total sleep times similar to those of controls. NES subjects reported more awakenings than did controls (1.5 ± 1.0 per night vs. 0.5 ± 0.5; p < 0.001), and their actigraphically monitored awakenings occurred earlier during sleep (at 128 min after sleep onset vs. 193 min, p = 0.01). NES subjects consumed food during 74% of their awakenings vs. 0% for the controls. The frequency with which awakenings were followed by food ingestion declined during the night, from 88.6% the first time to 65.8% the second time, and so on.

Analysis of feeding of &lt;i&gt;Sardina pilchardus&lt;/i&gt; (Walbaum, 1792) larval stages in the central Cantabrian Sea

SUMMARY: Diet analysis of larval fish may clarify the role that zooplankton—not only its abundance but also its size structure and taxonomic composition—may have on larval growth and subsequent recruitment levels. Taking into account the increase in size during larval stages, we followed a larval size-dependent approach for the analysis of prey size in the diet of larval sardine (Sardina pilchardus). Studies on feeding patterns of clupeid larvae typically involve a problem due to regurgitation and defecation of gut contents during capture. Therefore, an alternative sampling method was tested in this study, but no significant differences from conventional methods were found. Despite the low feeding incidence observed (23%), we found a circadian feeding pattern with the highest mean gut contents after dawn, decreasing during the day and with the lowest values at night. Diet was mostly composed of copepod developmental stages, mainly nauplii, and prey size increased with larval size following a power function. Maximum and mean prey size were related to larval mouth gape, though other factors may be restricting the maximum prey size ingested, since most prey width values were between 20 and 40% of larval mandible width.