Limits to sustained energy intake

2001 ◽  
Vol 204 (11) ◽  
pp. 1937-1946 ◽  
Author(s):  
M. S. Johnson ◽  
S. C. Thomson ◽  
J. R. Speakman
Keyword(s):  
Body Mass ◽  
Litter Size ◽  
Reproductive Output ◽  
Resting Metabolic Rate ◽  
Principal Component ◽  
Mammary Tissue ◽  
Tissue Mass ◽  
Litter Mass ◽  
Morphological Variable ◽  
Peak Lactation

SUMMARY Links between resting metabolic rate (RMR) and reproductive output have been previously sought at both inter- and intraspecific levels, but have only been found in some interspecific studies. We aimed to examine correlations between RMR measured both prior to breeding and at peak lactation with litter size and litter mass in Mus musculus. By manipulating the litter size of some females at birth, we aimed to establish the direction of causality in any correlation between litter size and RMR. Correlations between maternal morphology and RMR, litter size and litter mass were also examined. Neither pre-breeding RMR nor mass-independent pre-breeding RMR was correlated with litter size or litter mass. RMR at peak lactation, however, was positively correlated with litter size and negatively correlated with mean pup mass. After correcting for the effects of body mass, residual peak lactation RMR was not correlated with litter size or litter mass. Body size was the major morphological variable influencing litter mass, offspring mass and asymptotic food intake. Mammary tissue mass was correlated with litter size when only the data for mice raising unmanipulated litters were used. RMR at peak lactation was significantly related to the principal component of morphology dominated by carcass mass. This study confirms the findings of previous intraspecific and some interspecific studies that found no correlation between RMR and reproductive output after the effects of body mass had been removed.

Effects of neurosecretory protein GL on food intake and fat accumulation under different dietary nutrient compositions in rats

2021 ◽  
Author(s):  
Keisuke Fukumura ◽  
Kenshiro Shikano ◽  
Yuaki Narimatsu ◽  
Eiko Iwakoshi-Ukena ◽  
Megumi Furumitsu ◽  
...  
Keyword(s):  
Food Intake ◽  
Feeding Behavior ◽  
Body Mass ◽  
Mass Gain ◽  
Chow Diet ◽  
Tissue Mass ◽  
Fat Accumulation ◽  
Intracerebroventricular Infusion ◽  
Body Mass Gain ◽  
Sucrose Diet

Abstract We recently identified a novel hypothalamic small protein, named neurosecretory protein GL (NPGL), which is involved in energy homeostasis in birds and mammals. However, whether the action of NPGL is influenced by nutritional composition remains unknown. Thus, we investigated the effect of chronic intracerebroventricular infusion of NPGL for 13 days on feeding behavior and body mass gain under a normal chow diet (NC), high-fat diet, high-sucrose diet (HSD), and medium-fat/medium-sucrose diet (MFSD) in rats. NPGL stimulated food intake of NC and MFSD, especially during the light period. By contrast, NPGL decreased body mass gain under NC and increased total white adipose tissue mass in HSD- and MFSD-fed rats. These data suggest that the effects of NPGL on feeding behavior, body mass gain, and fat accumulation depend on nutrient type. Among them, sucrose in diets seems to contribute to fat accumulation elicited by NPGL.

NEURAL FACTORS IN THE MAINTENANCE OF LACTATION IN THE RAT

1967 ◽  
Vol 38 (1) ◽  
pp. 51-59 ◽  
Author(s):  
J. A. EDWARDSON ◽  
J. T. EAYRS
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Quantitative Relationship ◽  
Mammary Tissue ◽  
Single Pair ◽  
Endocrine Response ◽  
Peripheral Innervation ◽  
Lactational Performance ◽  
Neural Factors

SUMMARY The role of the peripheral innervation of mammary tissue in the maintenance of lactation has been investigated by the procedure of selective thelectomy combined with denervation of the posterior thoracic nipples. When suckling is restricted to a single pair of nipples bilateral transection of the three adjacent nerves supplying a nipple arrests lactation completely; partial denervation is associated with a reduced level of lactational performance which is directly related to the concentration of the residual innervation. Increase in litter size is associated with an overall increase in milk-yield up to a limit beyond which the addition of further young to the litter is without effect. It is inferred that there is a quantitative relationship between the neural stimulus of suckling and the endocrine response of the hypothalamopituitary system.

scholarly journals The energy allocation trade-offs underlying life history traits in hypometabolic strepsirhines and other primates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bruno Simmen ◽  
Luca Morino ◽  
Stéphane Blanc ◽  
Cécile Garcia
Keyword(s):  
Life History ◽  
Energy Expenditure ◽  
Body Mass ◽  
Life History Traits ◽  
Brain Size ◽  
Energy Allocation ◽  
Interbirth Interval ◽  
Energy Investment ◽  
Litter Mass ◽  
Trade Offs

AbstractLife history, brain size and energy expenditure scale with body mass in mammals but there is little conclusive evidence for a correlated evolution between life history and energy expenditure (either basal/resting or daily) independent of body mass. We addressed this question by examining the relationship between primate free-living daily energy expenditure (DEE) measured by doubly labeled water method (n = 18 species), life history variables (maximum lifespan, gestation and lactation duration, interbirth interval, litter mass, age at first reproduction), resting metabolic rate (RMR) and brain size. We also analyzed whether the hypometabolic primates of Madagascar (lemurs) make distinct energy allocation tradeoffs compared to other primates (monkeys and apes) with different life history traits and ecological constraints. None of the life-history traits correlated with DEE after controlling for body mass and phylogeny. In contrast, a regression model showed that DEE increased with increasing RMR and decreasing reproductive output (i.e., litter mass/interbirth interval) independent of body mass. Despite their low RMR and smaller brains, lemurs had an average DEE remarkably similar to that of haplorhines. The data suggest that lemurs have evolved energy strategies that maximize energy investment to survive in the unusually harsh and unpredictable environments of Madagascar at the expense of reproduction.

Limits to sustained energy intake

2001 ◽  
Vol 204 (11) ◽  
pp. 1947-1956 ◽  
Author(s):  
M. S. Johnson ◽  
S. C. Thomson ◽  
J. R. Speakman
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Litter Size ◽  
Resting Metabolic Rate ◽  
Control Group ◽  
Lower Mass ◽  
Daily Food Intake ◽  
Energy Demands ◽  
Daily Food ◽  
Pregnancy And Lactation

SUMMARYTo determine whether mice were limited in their capacity to absorb energy during late lactation, we attempted to increase the energy burden experienced by a group of female mice during late lactation by mating them at the postpartum oestrus, hence combining the energy demands of pregnancy and lactation. These experimental mice were therefore concurrently pregnant and lactating in their first lactation, and were followed through a normal second lactation. In a control group, females also underwent two lactations but sequentially, with the second mating after the first litter had been weaned. Maternal mass and food intake were measured throughout the first lactation, second pregnancy and second lactation. Maternal resting metabolic rate (RMR) was measured prior to the first mating and then at the peak of both the first and second lactations. Litter size and litter mass were also measured throughout both lactations. In the first lactation, experimental mice had a lower mass-independent RMR (F1,88=5.15, P=0.026) and raised significantly heavier pups (t=2.77, d.f.=32, P=0.0093) than the control mice. Experimental mice delayed implantation at the start of the second pregnancy. The extent of the delay was positively related to litter size during the first lactation (F1,19=4.58, P=0.046) and negatively related to mean pup mass (F1,19=5.78, P=0.027) in the first lactation. In the second lactation, the experimental mice gave birth to more (t=2.75, d.f.=38, P=0.0092) and lighter (t=−5.01, d.f.=38, P<0.0001) pups than did the controls in their second lactation. Maternal asymptotic daily food intake of control mice in the second lactation was significantly higher (t=−4.39, d.f.=37, P=0.0001) than that of the experimental mice and higher than that of controls during their first lactation. Despite the added burden on the experimental females during their first lactation, there was no increase in their food intake, which suggested that they might be limited by their capacity to absorb energy. However, control females appeared to be capable of increasing their asymptotic food intake beyond the supposed limits estimated previously, suggesting that the previously established limit was not a fixed central limitation on food intake. As RMR increased in parallel with the increase in food intake during the second lactation of control mice, the sustained energy intake remained at around 7.0×RMR.

scholarly journals Influence of body composition on physical activity validation studies using doubly labeled water

2004 ◽  
Vol 96 (4) ◽  
pp. 1357-1364 ◽  
Author(s):  
Louise C. Mâsse ◽  
Janet E. Fulton ◽  
Kathleen L. Watson ◽  
Matthew T. Mahar ◽  
Michael C. Meyers ◽  
...  
Keyword(s):  
Physical Activity ◽  
Body Composition ◽  
Energy Expenditure ◽  
Body Mass ◽  
Resting Metabolic Rate ◽  
Fat Free Mass ◽  
Doubly Labeled Water ◽  
Comparison Analysis ◽  
Methods Comparison ◽  
Statistical Procedures

This study investigated the influence of two approaches (mathematical transformation and statistical procedures), used to account for body composition [body mass or fat-free mass (FFM)], on associations between two measures of physical activity and energy expenditure determined by doubly labeled water (DLW). Complete data for these analyses were available for 136 African American (44.1%) and Hispanic (55.9%) women (mean age 50 ± 7.3 yr). Total energy expenditure (TEE) by DLW was measured over 14 days. Physical activity energy expenditure (PAEE) was computed as 0.90 × TEE - resting metabolic rate. During week 2, participants wore an accelerometer for 7 consecutive days and completed a 7-day diary. Pearson's product-moment correlations and three statistical procedures (multiple regressions, partial correlations, and allometric scaling) were used to assess the effect of body composition on associations. The methods-comparison analysis was used to study the effect of body composition on agreement. The statistical procedures demonstrated that associations improved when body composition was included in the model. The accelerometer explained a small but meaningful portion of the variance in TEE and PAEE after body mass was accounted for. The methods-comparison analysis confirmed that agreement with DLW was affected by the transformation. Agreement between the diary (transformed with body mass) and TEE reflected the association that exists between body mass and TEE. These results suggest that the accelerometer and diary accounted for a small portion of TEE and PAEE. Most of the variance in DLW-measured energy expenditure was explained by body mass or FFM.

Abstract 49: Adipose-Specific Knockout of Trib1 Reduces Plasma Lipids and Diet-Induced Insulin Resistance, and Increases Circulating Adiponectin

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Mikhaila A Smith ◽  
Jian Cui ◽  
Sumeet A Kheterpal ◽  
Daniel J Rader ◽  
Robert C Bauer
Keyword(s):  
Body Mass ◽  
Plasma Lipids ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Genetic Associations ◽  
Tissue Mass ◽  
Fed State ◽  
Plasma Adiponectin ◽  
Metabolic Role

Tribbles-1 (TRIB1) was recently identified through genome-wide association studies as a novel mediator of plasma lipids and coronary artery disease in humans. While subsequent in vivo mouse work confirmed a role for hepatic TRIB1 in these associations, little is known about metabolic roles for extra-hepatic Trib1. Interestingly, SNPs near the TRIB1 gene are significantly associated with circulating adiponectin levels in humans, suggesting a metabolic role for adipose TRIB1 . To further investigate this, we generated adipose-specific Trib1 KO mice (Trib1_ASKO) by crossing Trib1 cKO mice to transgenic Adiponectin-Cre mice. Chow-fed Trib1_ASKO mice exhibited no differences in adipose tissue mass and overall body mass as compared to control littermates (N=8/group). However, Trib1_ASKO mice had reduced total (-16.9%, p <0.01), HDL (-16.7%, p <0.01), and non-HDL cholesterol (-17.3%, p =0.068), as well as plasma triglycerides (-28.6%, p <0.001) as compared to WT mice. Trib1_ASKO mice also had increased plasma adiponectin levels, a finding more pronounced in female mice (+33.3%, p <0.001) than in males (+16.4%, p =0.072). Despite this increase, transcript levels of adipoQ were moderately decreased in Trib1_ASKO mice, suggesting a post-transcriptional mode of regulation. Transcript and protein levels of C/EBPα, the best described target of Trib1 and a key regulator of adipogenesis, remained unchanged. To further investigate the metabolic consequences of adipose-specific KO of Trib1 , WT and Trib1_ASKO mice were fed high-fat diet (HFD, 45% kCal fat) for 12 weeks to induce obesity. HFD-fed Trib1_ASKO mice had reduced fasting plasma glucose (-22.3%, p <0.05), insulin (-38.2%, p <0.05), and glucose tolerance (-19.8% AUC, p <0.05) compared to control mice. Body mass and fat mass of HFD-fed Trib1_ASKO mice remained unchanged from WT, and the reductions in plasma lipids and increase in plasma adiponectin persisted in the HFD-fed state. In summary, we present here the first in vivo validation of the human genetic association between TRIB1 and plasma adiponectin, and provide evidence suggesting that adipose TRIB1 contributes to the genetic associations observed in humans between TRIB1 and multiple metabolic parameters.

The ecophysiology of survival in juvenile red kangaroos Macropus rufus: greater demands and higher costs.

2004 ◽  
Vol 26 (2) ◽  
pp. 161 ◽  
Author(s):  
AJ Munn ◽  
TJ Dawson
Keyword(s):  
Body Mass ◽  
Arid Regions ◽  
Resting Metabolic Rate ◽  
High Quality ◽  
Energy Turnover ◽  
Growth And Survival ◽  
Risk Of Predation ◽  
Macropus Rufus ◽  
High Fibre ◽  
Lactating Females

Red kangaroos (Macropus rufus) are large (> 20 kg) herbivorous marsupials common to the arid and semi-arid regions of inland Australia. The population dynamics of M. rufus is tightly linked to environmental factors, which operate partly through the survival of juveniles. A crucial period is the young-at-foot (YAF) stage when juveniles have permanently left the mother?s pouch. YAF and weaned kangaroos have the highest drought-related mortalities of any cohort and show notable differences from adults in their basic physiology. YAF and weaned M. rufus, for example, had a resting metabolic rate (kJ kg-1 d-1) twice that of mature females and 1.5 times that expected for an adult marsupial of equivalent body mass (i.e., kJ kg-0.75 d-1). This greater energy turnover was largely explained by their metabolic demands for growth; juveniles required 70 - 95% of the digestible energy intake (kJ d-1) of mature, non-lactating females. Meeting these costs may not be a problem for juveniles when high-quality, low-fibre forage is available, but they were constrained when only hard-to-digest, high-fibre forage was available. YAF and weaned kangaroos, for example, were unable to sustain growth on forages of more than 40 ? 50% fibre, fibre levels characteristic of forages in arid regions during drought. Yet mature, non-lactating females were capable of maintaining body mass on similar forage. Additionally, juvenile M. rufus required relatively more water than adults for thermoregulation (by up to 2.5-fold), especially under hot conditions, and may need to drink more frequently than adults. Thus, juveniles appear constrained to remain close to water points, increasing their risk of predation and limiting their ability to find the high-quality forage needed for their growth and survival.

Effects of body mass on courtship, pairing, and reproduction in captive mallards

1989 ◽  
Vol 67 (2) ◽  
pp. 495-501 ◽  
Author(s):  
R. K. Pattenden ◽  
D. A. Boag
Keyword(s):  
Clutch Size ◽  
Body Mass ◽  
Reproductive Output ◽  
Breeding Biology ◽  
Laying Date ◽  
Body Reserves ◽  
Pair Bonds ◽  
Breeding Grounds ◽  
Delayed Initiation ◽  
Nutrient Reserves

The object of this study was to examine the influence of body mass, a measure of nutrient reserves, on the breeding biology of captive mallards. Low body mass delayed initiation of courtship and pairing, and decreased the number of permanent pair bonds formed. However, pairing date was not correlated with laying date. Low body mass during winter had a greater influence on laying date than low body mass during spring, but neither affected clutch size. This suggests that an individual arriving on the breeding grounds with low body reserves relative to others will have a lower reproductive output that year.

Reproductive changes in a cyclic population of snowshoe hares

2001 ◽  
Vol 79 (11) ◽  
pp. 2101-2108 ◽  
Author(s):  
Carol I Stefan ◽  
Charles J Krebs
Keyword(s):  
Pregnancy Rate ◽  
Breeding Season ◽  
Litter Size ◽  
Reproductive Output ◽  
Yukon Territory ◽  
The Body ◽  
Decline Phase ◽  
Snowshoe Hares ◽  
Early Increase ◽  
Changes In Pregnancy

Reproductive output was estimated for a cyclic population of snowshoe hares (Lepus americanus) in the Kluane Lake region of the southwest Yukon Territory. Data collected by five researchers were collated over 8 years (1989–1996). Pregnant hares were captured and held in cages until they gave birth so that reproductive characteristics could be measured. Pregnancy rate, litter size, and neonate size fluctuated significantly throughout the cycle, changes occurring about 2 years before corresponding changes in density. Pregnancy rates were nearly 100% early in the breeding season, but declined up to 20% in the last gestation periods of the year. The number of litters produced in a breeding season varied between two (decline phase) and four (low, early increase phase). Litter size varied among years as well as among litters within a year, larger litters being born later in the breeding season. The body mass and size of newborn hares varied by 5–33% among years. The combined changes in pregnancy rate and litter size resulted in a cyclic change in total reproductive output ranging from a low of 6.9 young per female during the decline phase to a maximum of 18.9 during the second year of the low and early increase phases.

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