A Novel Automated System Yields Reproducible Temporal Feeding Patterns in Laboratory Rodents

ABSTRACT Background The impact of temporal feeding patterns remains a major unanswered question in nutritional science. Progress has been hampered by the absence of a reliable method to impose temporal feeding in laboratory rodents, without the confounding influence of food-hoarding behavior. Objective The aim of this study was to develop and validate a reliable method for supplying crushed diets to laboratory rodents in consistent, relevant feeding patterns for prolonged periods. Methods We programmed our experimental feeding station to deliver a standard diet [StD; Atwater Fuel Energy (AFE) 13.9% fat] or high-fat diet (HFD; AFE 45% fat) during nocturnal grazing [providing 1/24th of the total daily food intake (tdF/I) of ad libitum–fed controls every 30 min] and meal-fed (3 × 1-h periods of ad libitum feeding) patterns in male rats (Sprague-Dawley: 4 wk old, 72–119 g) and mice [C57/Bl6J wild-type (WT): 6 mo old, 29–37 g], and ghrelin-null littermates (Ghr−/−; 27–34 g). Results Grazing yielded accurate, consistent feeding events in rats, with an approximately linear rise in nocturnal cumulative food intake [tdF/I (StD): 97.4 ± 1.5% accurate compared with manual measurement; R2 = 0.86; tdF/I (HFD): 99.0 ± 1.4% accurate; R2 = 0.86]. Meal-feeding produced 3 nocturnal meals of equal size and duration in StD-fed rats (tdF/I: 97.4 ± 0.9% accurate; R2 = 0.90), whereas the second meal size increased progressively in HFD-fed rats (44% higher on day 35 than on day 14; P < 0.01). Importantly, cumulative food intake in grazing and meal-fed rats was identical. Similar results were obtained in WT mice except that less restricted grazing induced hyperphagia (compared with meal-fed WT mice; P < 0.05 from day 1). This difference was abolished in Ghr−/− mice, with meal initiation delayed and meal duration enhanced. Neither pattern elevated corticosterone secretion in rats, but meal-feeding aligned ultradian pulses. Conclusions We have established a consistent, measurable, researcher-defined, stress-free method for imposing temporal feeding patterns in rats and mice. This approach will facilitate progress in understanding the physiologic impact of feeding patterns.

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Effects of meal frequency on energy utilization in rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1988.255.4.r616 ◽

1988 ◽

Vol 255 (4) ◽

pp. R616-R621 ◽

Cited By ~ 1

Author(s):

J. O. Hill ◽

J. C. Anderson ◽

D. Lin ◽

F. Yakubu

Keyword(s):

Body Composition ◽

Body Weight ◽

Food Intake ◽

Energy Expenditure ◽

Body Weight Gain ◽

Energy Utilization ◽

Male Rats ◽

Major Influence ◽

Meal Frequency ◽

Ad Libitum

The effects of differences in meal frequency on body weight, body composition, and energy expenditure were studied in mildly food-restricted male rats. Two groups were fed approximately 80% of usual food intake (as periodically determined in a group of ad libitum fed controls) for 131 days. One group received all of its food in 2 meals/day and the other received all of its food in 10-12 meals/day. The two groups did not differ in food intake, body weight, body composition, food efficiency (carcass energy gain per amount of food eaten), or energy expenditure at any time during the study. Both food-restricted groups had a lower food intake, body weight gain, and energy expenditure than a group of ad libitum-fed controls. In conclusion, these results suggest that amount of food eaten, but not the pattern with which it is ingested, has a major influence on energy balance during mild food restriction.

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Genetic components of growth and ultrasonic fat depth traits in Meishan and Large White pigs and their reciprocal crosses

Animal Science ◽

10.1017/s0003356100020626 ◽

1992 ◽

Vol 54 (1) ◽

pp. 105-115 ◽

Cited By ~ 21

Author(s):

C. S. Haley ◽

E. d'Agaro ◽

M. Ellis

Keyword(s):

Growth Rate ◽

Food Intake ◽

Performance Test ◽

Subcutaneous Fat ◽

Additive Effect ◽

Food Conversion ◽

Large White ◽

Male And Female ◽

Ad Libitum ◽

The Impact

AbstractGenes from the Chinese Meishan pig have the potential to enhance reproductive performance of European pigs. In order to allow prediction of the impact of Meishan genes in a range of alternative improvement programmes all traits of economic importance must be evaluated and genetic crossbreeding effects estimated. Entire male and female pigs of four genotypes, purebred Meishan (MS) and Large White (LW) pigs and both reciprocal Fl crossbred genotypes (MS ♂ × LW ♀ and LW ♂ × MS ♀), were farrowed in Edinburgh and subsequently performance tested at either Edinburgh or Newcastle. In Edinburgh, animals were penned in groups of four and fed ad libitum between pen mean weights of approximately 30 and 80 kg. At the end of test fat depths at the shoulder, last rib and loin were measured ultrasonically. In Newcastle, animals were penned in groups of six and fed ad libitum between pen mean weights of approximately 30 and 70 kg. Genotypic means and genetic crossbreeding effects (additive and heterosis direct effects and additive maternal effects) were estimated using restricted maximum likelihood.When compared with the LW, the direct additive effect of genes from the MS produced increased growth rate up to the time of weaning, no change in growth rate between weaning and start of test and greatly reduced growth rate during the performance test. The maternal additive effect of genes from the MS was to reduce growth rate up to the time of weaning, with little effect thereafter. There was substantial direct heterosis for growth rate in all periods measured, but heterosis was less in males than in females during the performance test. The combined effect was such that, within sex, the LW and the two crossbred genotypes were of similar ages when they reached 70 and 80 kg, but MS pigs were 38 to 60 days older. The direct additive effect of MS genes was to increase subcutaneous fat levels and there was little evidence for the effects of maternal genes or direct heterosis on these traits. There was a direct additive effect of MS genes reducing food intake and increasing food conversion ratio and there was direct heterosis for increased food intake. There were significant interactions between genotype and sex. Male and female LW pigs had a similar performance but male MS pigs had slower growth rates on the performance test with lower food intakes, food conversion ratios and subcutaneous fat levels than the females.

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The flexibility of feeding patterns in individually housed pigs

Animal Science ◽

10.1017/s135772980005181x ◽

2000 ◽

Vol 70 (3) ◽

pp. 457-469 ◽

Cited By ~ 13

Author(s):

H. L. I. Bornett ◽

C. A. Morgan ◽

A. B. Lawrence ◽

J. Mann

Keyword(s):

Food Intake ◽

Feeding Behaviour ◽

Live Weight ◽

Feeding Pattern ◽

Time Budgets ◽

Feeding Patterns ◽

Large White ◽

Period 2 ◽

Access To Food ◽

The Impact

AbstractGroup-housed pigs may be prevented from expressing their desired feeding pattern by more dominant individuals in the group. Indeed, when compared with individually housed pigs, group housed pigs eat less frequent, but larger meals. Therefore, it would be advantageous for pigs to have flexible feeding patterns in order to decrease the impact of group housing. The aim of this study was to assess the flexibility of feeding patterns by restricting the time of access to food of pigs previously given food ad libitum and then returning them to 24-h access. Thirty-two Large White x Landrace pigs were used in an experiment of two blocks (16 pigs per block) each comprising three, 2-week periods. In each block; during period 1, all pigs were allowed 24-h access to food after which, in period 2, eight of the pigs had access to the feeder restricted between 11:00 and 13:00 h of each day. The remaining eight pigs continued on 24-h access to food and acted as controls. In period 3, all pigs were again returned to 24-h access to food. Daily feeding pattern and food intake were recorded throughout. Behavioural observations in the form of scan samples were made and pigs were weighed twice a week. In period 2 the restricted pigs had fewer visits to the feeder per day, 34·0 v. 70·1 (P < 0·001); of a longer duration, 98·3 v. 64·5 s (P < 0·01); with a higher food intake per visit, 64·9 v. 33·3 g (P < 0·001) than the control pigs. Daily food intake and live-weight gain were lower (P < 0·001) for the restricted pigs in period 2 than for the control pigs. Restricted pigs spent more time rooting (P < 0·05), and less time sleeping (P < 0·05) than the control pigs in period 2. In addition, there was a trend for pigs to spend more time alert in the observation session prior to access to food in the second period when they were restricted and they made attempts to gain access to the feeders in this session. An indication of flexibility was gained by comparing feeding behaviour and time budgets between periods 1 and 3. The pigs that experienced a period of restricted feeding either resumed their previous behaviour or showed the same trend as the controls. In periods 1 and 3 daily feeder visits were 66·2 and 68·1 for control pigs, and 65·6 and 67·1 for restricted pigs. Mean durations of visits were 79·3 and 47·5 s, and 74·4 and 61·7 s respectively. It was concluded that feeding behaviour was flexible and time budgets were resilient across periods.

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Decreased brown adipose tissue thermogenic activity following a reduction in brain serotonin by intraventricular p-chlorophenylalanine

Bioscience Reports ◽

10.1007/bf01121875 ◽

1987 ◽

Vol 7 (2) ◽

pp. 121-127 ◽

Cited By ~ 16

Author(s):

Nigel J. Fuller ◽

Dorothy M. Stirling ◽

Stephen Dunnett ◽

Gavin P. Reynolds ◽

Margaret Ashwell

Keyword(s):

Adipose Tissue ◽

Food Intake ◽

Brown Adipose Tissue ◽

Male Rats ◽

Brain Serotonin ◽

Interscapular Brown Adipose Tissue ◽

Sympathetic Control ◽

Brown Adipose ◽

Ad Libitum ◽

Established Role

The effects of reducing brain serotonin (5-HT) levels by means of intracerebral-ventricular injections of the tryptophan antagonist p-chlorophenylalanine (PCPA) were investigated in male rats. Six days after the operation, PCPA-treated rats, either fed ad libitum or pair-fed to the food intake of control rats, showed decreased thermogenic activity and capacity in their interscapular brown adipose tissue (BAT) and also increased fat storage in their white adipose tissue (WAT). These results indicate that serotonergic synapses might play a regulatory role in the sympathetic control of BAT thermogenesis and in the rate of WAT deposition (by an as yet unidentified mechanism), in addition to their well established role in controlling food intake.

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Acute inflammation reduces kisspeptin immunoreactivity at the arcuate nucleus and decreases responsiveness to kisspeptin independently of its anorectic effects

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00081.2010 ◽

2010 ◽

Vol 299 (1) ◽

pp. E54-E61 ◽

Cited By ~ 43

Author(s):

J. M. Castellano ◽

A. H. Bentsen ◽

M. Romero ◽

R. Pineda ◽

F. Ruiz-Pino ◽

...

Keyword(s):

Food Intake ◽

Acute Inflammation ◽

Arcuate Nucleus ◽

Metabolic Stress ◽

Reproductive Function ◽

Male Rats ◽

Inflammatory Phase ◽

Gonadotropic Function ◽

Gonadotropic Axis ◽

The Impact

Severe inflammatory challenges are frequently coupled to decreased food intake and disruption of reproductive function, the latter via deregulation of different signaling pathways that impinge onto GnRH neurons. Recently, the hypothalamic Kiss1 system, a major gatekeeper of GnRH function, was suggested as potential target for transmitting immune-mediated repression of the gonadotropic axis during acute inflammation, and yet key facets of such a phenomenon remain ill defined. Using lipopolysaccharide S (LPS)-treated male rats as model of inflammation, we document herein the pattern of hypothalamic kisspeptin immunoreactivity (IR) and hormonal responses to kisspeptin during the acute inflammatory phase. LPS injections induced a dramatic but transient drop of serum LH and testosterone levels. Suppression of gonadotropic function was associated with a significant decrease in kisspeptin-IR in the arcuate nucleus (ARC) that was not observed under conditions of metabolic stress induced by 48-h fasting. In addition, absolute responses to kisspeptin-10 (Kp-10), in terms of LH and testosterone secretion, were significantly attenuated in LPS-treated males that also displayed a decrease in food intake and body weight. Yet pair-fed males did not show similar alterations in LH and testosterone secretory responses to Kp-10, whose magnitude was preserved, if not augmented, during food restriction. In summary, our data document the impact of acute inflammation on kisspeptin content at the ARC as key center for the neuroendocrine control of reproduction. Our results also suggest that suppressed gonadotropic function following inflammatory challenges might involve a reduction in absolute responsiveness to kisspeptin that is independent of the anorectic effects of inflammation.

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Pyroglutamylated RFamide Peptide 43 Stimulates the Hypothalamic-Pituitary-Gonadal Axis via Gonadotropin-Releasing Hormone in Rats

Endocrinology ◽

10.1210/en.2007-1562 ◽

2008 ◽

Vol 149 (9) ◽

pp. 4747-4754 ◽

Cited By ~ 41

Author(s):

Sejal R. Patel ◽

Kevin G. Murphy ◽

Emily L. Thompson ◽

Michael Patterson ◽

Annette E. Curtis ◽

...

Keyword(s):

Food Intake ◽

Intraperitoneal Administration ◽

Gonadotropin Releasing Hormone ◽

Male Rats ◽

Sex Steroid ◽

The Novel ◽

Gnrh Release ◽

Ad Libitum ◽

Influence Behavior

Although it is established that other members of the RFamide family stimulate the hypothalamic-pituitary-gonadal axis, the influence of the novel pyroglutamylated RFamide peptide 43 (QRFP43) is not known. We show intracerebroventricular (icv) administration of QRFP43 (2 nmol) to male rats increased plasma LH and FSH levels at 40 min after injection. icv administration of 3 nmol QRFP43 did not affect food intake in ad-libitum-fed male rats. The icv administration of 2 nmol QRFP43 did not significantly influence behavior in male rats. Intraperitoneal administration of doses up to 1200 nmol/kg QRFP43 in male rats did not significantly influence circulating gonadotropin or sex steroid levels. In vitro, QRFP43 stimulated GnRH release from hypothalamic explants from male rats and from GT1-7 cells. Pretreatment with a GnRH receptor antagonist, cetrorelix, blocked the increase in plasma LH levels after icv administration of QRFP43 (2 nmol). These results suggest that icv QRFP43 activates the hypothalamic-pituitary-gonadal axis via GnRH.

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High Caloric Diet Induces Memory Impairment and Disrupts Synaptic Plasticity in Aged Rats

Current Issues in Molecular Biology ◽

10.3390/cimb43030162 ◽

2021 ◽

Vol 43 (3) ◽

pp. 2305-2319

Author(s):

Sara L. Paulo ◽

Catarina Miranda-Lourenço ◽

Rita F. Belo ◽

Rui S. Rodrigues ◽

João Fonseca-Gomes ◽

...

Keyword(s):

Synaptic Plasticity ◽

Memory Impairment ◽

Overweight And Obesity ◽

Synaptic Function ◽

Male Rats ◽

Standard Diet ◽

Aged Rats ◽

High Caloric Diet ◽

The Impact

The increasing consumption of sugar and fat seen over the last decades and the consequent overweight and obesity, were recently linked with a deleterious effect on cognition and synaptic function. A major question, which remains to be clarified, is whether obesity in the elderly is an additional risk factor for cognitive impairment. We aimed at unravelling the impact of a chronic high caloric diet (HCD) on memory performance and synaptic plasticity in aged rats. Male rats were kept on an HCD or a standard diet (control) from 1 to 24 months of age. The results showed that under an HCD, aged rats were obese and displayed significant long-term recognition memory impairment when compared to age-matched controls. Ex vivo synaptic plasticity recorded from hippocampal slices from HCD-fed aged rats revealed a reduction in the magnitude of long-term potentiation, accompanied by a decrease in the levels of the brain-derived neurotrophic factor receptors TrkB full-length (TrkB-FL). No alterations in neurogenesis were observed, as quantified by the density of immature doublecortin-positive neurons in the hippocampal dentate gyrus. This study highlights that obesity induced by a chronic HCD exacerbates age-associated cognitive decline, likely due to impaired synaptic plasticity, which might be associated with deficits in TrkB-FL signaling.

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Feeding motivation of sows fed a sugarbeet pulp diet

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600022571 ◽

1992 ◽

Vol 1992 ◽

pp. 146-146

Author(s):

F Brouns ◽

S A Edwards ◽

P R English

Keyword(s):

Food Intake ◽

Taste Aversion ◽

Metabolic Effects ◽

Standard Diet ◽

Measured Rate ◽

Feeding Motivation ◽

High Fibre ◽

Ad Libitum ◽

Voluntary Food Intake

Voluntary food intake of dry sows fed ad libitum diets containing high levels of unmolassed sugarbeet pulp (SBP) was low in comparison to those fed other high fibre diets (Brouns et al., 1991). It is not known whether this is caused by a taste aversion, or whether physical/metabolic effects during digestion restrict intake. In this experiment the feeding motivation of sows fed SBP diets was determined by measuring their rate of feeding.Twelve multiparous pregnant sows housed in straw bedded pens, but individually fed in feeding stalls, were used for this experiment. The sows were allocated between two treatments according to their measured rate of eating when given a standard diet on 2 pretrial days. Treatments were 2.3 kg of a diet containing 500g/kg SBP or 2.0 kg of a barley-based diet (C) (Table 1) providing the same total DE. Both diets were fed once a day in pelleted form. Any refusals were recorded to calculate intake.

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Effect of opioid receptors agonists on feeding behaviour using different diets in ad libitum fed neonatal chicken

Czech Journal of Animal Science ◽

10.17221/2/2016-cjas ◽

2017 ◽

Vol 62 (No. 3) ◽

pp. 98-109

Author(s):

S. Arva ◽

M. Zendehdel ◽

Y. EbrahimNezhad ◽

J. Ghiasi Ghalehkandi ◽

S. Hassanpour ◽

...

Keyword(s):

Food Intake ◽

Opioid Receptor ◽

Feeding Behaviour ◽

Receptor Agonist ◽

Energy Ratio ◽

Standard Diet ◽

Opioid Receptor Agonist ◽

Group A ◽

Ad Libitum

Despite progress in studying the role of opioids in reward, the effect of opioid receptors on feeding behaviour in ad libitum fed meat-type chicken offered different diet types is still unclear. So in this study, 12 experiments (each included 4 groups) were designed to determine the role of μ, δ, and κ receptors with different diets on feeding responses in ad libitum fed neonatal chicken. In Experiment 1, group A chicken were intracerebroventricularly (ICV) injected with saline, groups B–D chicken were ICV injected with DAMGO (µ-opioid receptor agonist; 125, 250, and 500 pmol), then standard diet without fat was offered. In Experiment 2, group A chicken were ICV injected with saline, groups B–D chicken were ICV injected with DAMGO (125, 250, and 500 pmol) and diet with nutrient energy ratio 20% below standard was provided to the birds. Experiments 3–4 were similar to Experiment 1, except after injection, diets containing nutrient energy ratio 20% above standard and standard diet with fat were provided to the birds, respectively. In Experiment 5, chicken were ICV injected with saline, DPDPE (δ-opioid receptor agonist) at doses of 20, 40, and 80 nmol, and then received standard diet without fat. Experiments 6–8 were similar to Experiment 5 in which diet containing nutrient energy ratio by 20% lower than standard, diet containing nutrient energy ratio by 20% higher than standard, and diet containing fat were provided instead of standard diet without fat to the birds, respectively. In Experiment 9, birds received ICV injection of saline and U-50488H (κ-opioid receptor agonist; 10, 20, and 40 nmol) and were provided standard diet without fat. Experiments 10–12 were similar to Experiment 9 but after ICV injection, birds were fed diet containing by 20% lower nutrient energy ratio, diet containing by 20% higher nutrient energy ratio, and standard diet containing fat, respectively. Then the cumulative food intake was measured until 180 min post injection. According to the results, DAMGO decreased while DPDPE and U-50488H increased the food intake (P < 0.05). These findings suggest endogenous governing food preferences via δ- and κ-opioid receptor in ad libitum fed neonatal chicken.

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Increased Male Offspring’s Risk of Metabolic-Neuroendocrine Dysfunction and Overweight after Fructose-Rich Diet Intake by the Lactating Mother

Endocrinology ◽

10.1210/en.2009-1353 ◽

2010 ◽

Vol 151 (9) ◽

pp. 4214-4223 ◽

Cited By ~ 38

Author(s):

Ana Alzamendi ◽

Daniel Castrogiovanni ◽

Rolf C. Gaillard ◽

Eduardo Spinedi ◽

Andrés Giovambattista

Keyword(s):

Food Intake ◽

Metabolic Disorders ◽

Tap Water ◽

Adult Life ◽

Male Offspring ◽

Sprague Dawley ◽

Leptin Sensitivity ◽

Lactating Mothers ◽

Ad Libitum ◽

The Impact

An adverse endogenous environment during early life predisposes the organism to develop metabolic disorders. We evaluated the impact of intake of an iso-caloric fructose rich diet (FRD) by lactating mothers (LM) on several metabolic functions of their male offspring. On postnatal d 1, ad libitum eating, lactating Sprague-Dawley rats received either 10% F (wt/vol; FRD-LM) or tap water (controls, CTR-LM) to drink throughout lactation. Weaned male offspring were fed ad libitum a normal diet, and body weight (BW) and food intake were registered until experimentation (60 d of age). Basal circulating levels of metabolic markers were evaluated. Both iv glucose tolerance and hypothalamic leptin sensitivity tests were performed. The hypothalamus was dissected for isolation of total RNA and Western blot analysis. Retroperitoneal (RP) adipose tissue was dissected and either kept frozen for gene analysis or digested to isolate adipocytes or for histological studies. FRD rats showed increased BW and decreased hypothalamic sensitivity to exogenous leptin, enhanced food intake (between 49–60 d), and decreased hypothalamic expression of several anorexigenic signals. FRD rats developed increased insulin and leptin peripheral levels and decreased adiponectinemia; although FRD rats normally tolerated glucose excess, it was associated with enhanced insulin secretion. FRD RP adipocytes were enlarged and spontaneously released high leptin, although they were less sensitive to insulin-induced leptin release. Accordingly, RP fat leptin gene expression was high in FRD rats. Excessive fructose consumption by lactating mothers resulted in deep neuroendocrine-metabolic disorders of their male offspring, probably enhancing the susceptibility to develop overweight/obesity during adult life.

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