Effects of foraging effort on body fat and food hoarding in Siberian hamsters

Day, Diane E.; Bartness, Timothy J.

doi:10.1002/1097-010x(20010215)289:3<162::aid-jez2>3.0.co;2-n

Cited by 42 publications

(58 citation statements)

References 18 publications

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“…In these studies, food intake remained mostly constant, with the exception of a slight increase at 10 revolutions per pellet (Day & Bartness 2001). Foodhoard size exhibited an inverse 'U' function with increases in foraging effort, as expected.…”

Section: External Factors (A)supporting

confidence: 81%

“…That is, animals with an active running wheel in their cage (free wheel/free food group) hoarded four times as much food as the sedentary controls (blocked wheel/ free food group). At the lower foraging efforts (10 and 50 revolutions), food hoarding also was greater (threefold increase) than that of the sedentary controls (blocked wheel/free food), but it was equal to or below sedentary control levels for animals forced to forage at the highest efforts (100 and 200 revolutions, respectively; Day & Bartness 2001). These studies, along with those from laboratory rats and birds, appear to confirm that food hoarding is an adaptive strategy to maintain energy homeostasis when food availability is either limited or unpredictable.…”

Section: External Factors (A)mentioning

confidence: 89%

“…R. Soc. B (2010) In a study examining the effects of foraging effort on food hoarding as well as on body fat levels (Day & Bartness 2001), we noticed that the epididymal white adipose tissue (EWAT) pad that surrounds the testes was decreased across all the foraging efforts even though total body fat only decreased at the highest foraging effort (Day & Bartness 2001). Therefore, we methodically and explicitly manipulated lipid levels by excising varying amounts of WAT by removing both EWAT pads (EWAT lipectomy; EWATx), both inguinal WAT pads (IWATx; each IWAT pad is approximately twice the size of an EWAT pad) or both EWAT and IWAT pads (EWATx þ IWATx; Dailey & Bartness 2008b).…”

Section: Peripheral Physiological Factorsmentioning

confidence: 99%

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Physiological mechanisms for food-hoarding motivation in animals

Keen-Rhinehart

Dailey

Bartness

2010

Phil. Trans. R. Soc. B

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The study of ingestive behaviour has an extensive history, starting as early as 1918 when Wallace Craig, an animal behaviourist, coined the terms 'appetitive' and 'consummatory' for the two-part sequence of eating, drinking and sexual behaviours. Since then, most ingestive behaviour research has focused on the neuroendocrine control of food ingestion (consummatory behaviour). The quantity of food eaten, however, is also influenced by the drive both to acquire and to store food (appetitive behaviour). For example, hamster species have a natural proclivity to hoard food and preferentially alter appetitive ingestive behaviours in response to environmental changes and/or metabolic hormones and neuropeptides, whereas other species would instead primarily increase their food intake. Therefore, with the strong appetitive component to their ingestive behaviour that is relatively separate from their consummatory behaviour, they seem an ideal model for elucidating the neuroendocrine mechanisms underlying the control of food hoarding and foraging. This review focuses on the appetitive side of ingestive behaviour, in particular food hoarding, attempting to integrate what is known about the neuroendocrine mechanisms regulating this relatively poorly studied behaviour. An hypothesis is formed stating that the direction of 'energy flux' is a unifying factor for the control of food hoarding.

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Section: External Factors (A)supporting

confidence: 81%

Section: External Factors (A)mentioning

confidence: 89%

Section: Peripheral Physiological Factorsmentioning

confidence: 99%

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Physiological mechanisms for food-hoarding motivation in animals

Keen-Rhinehart

Dailey

Bartness

2010

Phil. Trans. R. Soc. B

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“…We used a wheel-running training regimen that eases the hamsters into their foraging efforts without large changes in body mass or food intake (Day and Bartness, 2001). Specifically, hamsters were given free access to the food pellets for 2 d while they adapted to the running wheel.…”

Section: Foraging Training Regimenmentioning

confidence: 99%

MTII attenuates ghrelin- and food deprivation-induced increases in food hoarding and food intake

Keen-Rhinehart

Bartness

2007

Hormones and Behavior

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Food deprivation triggers a constellation of physiological and behavioral changes including increases in peripherally-produced ghrelin and centrally-produced agouti-related protein (AgRP). Upon refeeding, food intake is increased in most species, however hamsters primarily increase food hoarding. Food deprivation-induced increases in food hoarding by Siberian hamsters are mimicked by peripheral ghrelin and central AgRP injections. Because food deprivation stimulates ghrelin as well as AgRP synthesis/release, food deprivation-induced increases in hoarding may be mediated by melanocortin 3 or 4 receptor (MC3/4-R) antagonism via AgRP, the MC3/4-R inverse agonist. Therefore, we asked: Can a MC3/4-R agonist block food deprivation-or ghrelin-induced increases in foraging, food hoarding and food intake? This was accomplished by injecting melanotan II (MTII), a synthetic MC3/4-R agonist, into the 3 rd ventricle in food deprived, fed or peripheral ghrelin injected hamsters and housed in a running wheel-based food delivery foraging system. Three foraging conditions were used: a) no running wheel access, non-contingent food, b) running wheel access, non-contingent or c) a foraging requirement for food (10 revolutions/pellet). Food deprivation was a more potent stimulator of foraging and hoarding than ghrelin. Concurrent injections of MTII completely blocked food deprivation-and ghrelin-induced increases in food intake and attenuated, but did not always completely block, food deprivation-and ghrelin-induced increases in food hoarding. Collectively, these data suggest that the MC3/4-R are involved in ghrelin-and food deprivation-induced increases in food intake, but other neurochemical systems, such as previously demonstrated with neuropeptide Y, also are involved in increases in food hoarding as well as foraging.

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“…Increases in imposed foraging effort in Siberian hamsters results in decreased food intake, food hoarding and foraging [48]. Compensation for increased energy demands are handled similarly to what has been shown for rats ( Figure 1B).…”

Section: Hoardingmentioning

confidence: 63%

Feeding behavior, obesity, and neuroeconomics

Rowland

Vaughan

Mathes

et al. 2008

Physiology & Behavior

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For the past 50 years, the most prevalent theoretical models for regulation of food intake have been based in the physiological concept of energy homeostasis. However, several authors have noted that the simplest form of homeostasis, stability, does not accurately reflect the actual state of affairs and most notably the recent upward trend in body mass index observed in the majority of affluent nations. The present review argues that processes of natural selection have more likely made us first and foremost behavioral opportunists that are adapted to uncertain environments, and that physiological homeostasis is subservient to that reality. Examples are presented from a variety of laboratory studies indicating that food intake is a function of the effort and/or time required to procure that food, and that economic decision making is central to understanding how much and when organisms eat. The discipline of behavioral economics has developed concepts that are useful for this enterprise, and some of these are presented. Lastly, we present demonstrations in which genetic or physiologic investigations using environmental complexity will lead to more realistic ideas about how to understand and treat idiopathic human obesity. The fact is that humans are eating more and gaining weight in favorable food environments in exactly the way predicted from some of these models, and this has implications for the appropriate way to treat obesity. KeywordsBehavioral economics; food intake; foraging; closed economy; weight regulation OverviewMost analysts agree that the contemporary increase in body mass index, both at a crosssectional population level and longitudinally within individuals, that is occurring in many parts of the world results from a combination of increased food intake and decreased physical activity [1]. In contrast to this observed increase, theoretical model(s) of control of food intake and body weight emphasize stability. These models are mostly biomedical in nature, meaning that physiological signals in the body and brain are hypothesized to act in a self-regulatory manner to produce an optimal or stable situation for the organism. The foundation of these models is the concept of homeostasis and body weight set point [2,3]. According to such models, if we eat more and gain weight, then several hormonal signals will act in the brain to inhibit further food seeking. Conversely, if we eat too little, the system will increase food seeking and intake, Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. and the net result will be relative stability of body weight across ...

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Effects of foraging effort on body fat and food hoarding in Siberian hamsters

Cited by 42 publications

References 18 publications

Physiological mechanisms for food-hoarding motivation in animals

Physiological mechanisms for food-hoarding motivation in animals

MTII attenuates ghrelin- and food deprivation-induced increases in food hoarding and food intake

Feeding behavior, obesity, and neuroeconomics

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