Maintenance energy requirements, energy retention and heat production of young obese (ob/ob) and lean mice fed a high-fat or a high-carbohydrate diet (original) (raw)
Related papers
1979
Maintenance energy requirements were estimated for female obese (ob/ob) and lean littermates housed at 33°.Mice were weaned at 21 days of age and fed either a high-carbohydrate or a high-fat diet at three levels of intake for 21 days. Linear regressions relating changes in total body energy to metabolizable-energy intake were used to estimate maintenance energy requirements. To maintain body energy at 33°,obese and lean mice required approximately 72 and 92 kcal per kg3/* per day, respectively. (One kilocalorie equals 4.184 kilojoules.) Diet did not sig nificantly affect maintenance energy requirements. Lean mice fed either diet and obese mice fed the high-carbohydrate diet retained 61% of the metabolizable energy consumed above the maintenance requirement. But obese mice fed the high-fat diet were more efficient; they retained 81% of the metabolizable energy consumed above maintenance. Lean mice deposited a greater percentage of the metabolizable energy available for gain as protein than did obese mice. As expected, maintenance require ments of lean mice housed at 33°were reduced (approximately 25%) compared with results from an earlier study conducted at 25 to 30°.But maintenance energy requirements of obese mice were not changed when the environmental temperature was increased to 33°.Even though obese mice were more efficient in retaining dietary energy than were lean mice at both temperatures examined, the differences were greater at 25 to 30°t han at 33°.
The Journal of nutrition, 1980
Maintenance energy requirements were estimated for female obese (ob/ob) and lean littermates housed at 33°.Mice were weaned at 21 days of age and fed either a high-carbohydrate or a high-fat diet at three levels of intake for 21 days. Linear regressions relating changes in total body energy to metabolizable-energy intake were used to estimate maintenance energy requirements. To maintain body energy at 33°,obese and lean mice required approximately 72 and 92 kcal per kg3/* per day, respectively. (One kilocalorie equals 4.184 kilojoules.) Diet did not sig nificantly affect maintenance energy requirements. Lean mice fed either diet and obese mice fed the high-carbohydrate diet retained 61% of the metabolizable energy consumed above the maintenance requirement. But obese mice fed the high-fat diet were more efficient; they retained 81% of the metabolizable energy consumed above maintenance. Lean mice deposited a greater percentage of the metabolizable energy available for gain as protein than did obese mice. As expected, maintenance require ments of lean mice housed at 33°were reduced (approximately 25%) compared with results from an earlier study conducted at 25 to 30°.But maintenance energy requirements of obese mice were not changed when the environmental temperature was increased to 33°.Even though obese mice were more efficient in retaining dietary energy than were lean mice at both temperatures examined, the differences were greater at 25 to 30°t han at 33°.
The Journal of physiology, 1984
The energy expenditure of normal and congenitally obese adult female Zucker rats has been measured by continuous indirect calorimetry for periods of 3-10 days at ambient temperatures varied from 30 to 5 degrees C. Rectal temperatures were also recorded. Exposure to cold caused no ill-effects in normal or obese rats. The rectal temperatures of obese rats were about 1 degree C lower than those of normal rats. The rectal temperatures of normal rats did not change measurably with ambient temperature; in obese rats rectal temperature rose slightly as ambient temperature fell. In normal and obese rats, energy expenditure showed a smooth, steeply sloping, negative relationship to ambient temperature. Energy expenditure per rat was higher in obese than in normal rats at all temperatures. The two slightly curvilinear regressions were nearly 'parallel', with a separation of about 40 kJ/day per rat at the mid-point. This study therefore does not confirm suggestions that obese Zucker ra...
British Journal of Nutrition, 1979
I. Groups of lean and genetically obese (oblob) mice were adapted to varying energy intakes and the 2. Lean mice gained less weight when fed above maintenance and lost less weight when fed below 3. Hepatic protein turnover (mg/d) was sigmoidally related to digestible energy intake in lean mice but 4. The changes in protein turnover resulted from changes in both the half-lives of protein synthesis and 5. In the lean mice, protein turnover in kidney and gut was not significantly changed with increasing 6. The findings suggest that protein turnover may be an important cycle for the regulation of energy I 86 B. G. MILLER A N D OTHERS . However, direct evidence for the involvement of protein turnover in either cold adaptation or the maintenance of energy balance is poor.
METHODOLOGICAL EVALUATION OF INDIRECT CALORIMETRY DATA IN LEAN AND OBESE RATS
Clinical and Experimental Pharmacology and Physiology, 1993
1. The applicability of current indirect calorimetry formulae to the study of energy and substrate balances on obese rats has been evaluated. The energy consumption of series of 60-day rats of Wistar, lean and obese Zucker stock were studied by means of direct and indirect calorimetry, and by establishing their energy balance through measurement of food intake and retention. Calorimetric studies encompassed a 24 h period, with gas and heat output measurements every 2 or 5 min, respectively, for direct and indirect calorimetry. 2. The analysis of fat composition (diet, whole rat, and synthesized and oxidized fat) showed only small variations that had only a limited effect on the overall energy equation parameters. 3. A gap in the nitrogen balance, which represents a urinary N excretion lower than the actual protein oxidized, resulted in significant deviations in the estimation of carbohydrate and lipid oxidized when using the equations currently available for indirect calorimetry. 4. Analysis of the amino acid composition of diet and rat protein as well as of the portion actually oxidized, and correcting for the nitrogen gap allowed the establishment of a set of equations that gave better coincidence of the calculated data with the measured substrate balance. 5. The measured heat output of all rats was lower than the estimated values calculated by means of either indirect calorimetry of direct energy balance measurement; the difference corresponded to the energy lost in water evaporation, and was in the range of one-fifth of total energy produced in the three rat stocks. 6. Wistar rats showed a biphasic circadian rhythm of substrate utilization, with alternate lipid synthesis/degradation that reversed that of carbohydrate, concordant with nocturnal feeding habits. Zucker rats did not show this rhythm; obese rats synthesized large amounts of fat during most of the light period, consuming fat at the end of the dark period, which suggests more diurnal feeding habits. Lean Zucker rats showed a similar, but less marked pattern. 7. The results obtained indicate that lean and obese rats can be studied using the same indirect calorimetry formulae provided that there is an adequate measure of protein oxidation and the composition of diet does not differ.
Obesity, 2013
Objective: Protein leverage plays a role in driving increased energy intakes that may promote weight gain. The influence of the protein to carbohydrate ratio (P:C) in diets of C57BL/6J mice on total energy intake, fat storage, and thermogenesis was investigated. Design and Methods: Male mice (9 weeks old) were provided ad libitum access to one of five isocaloric diets that differed in P:C. Food intake was recorded for 12 weeks. After 16 weeks, white adipose tissue (WAT) and brown adipose tissue (BAT) deposits were dissected, weighed, and the expression levels of key metabolic regulators were determined in BAT. In a separate cohort, body surface temperature was measured in response to 25 diets differing in protein, fat, and carbohydrate content. Results: Mice on low P:C diets (9:72 and 17:64) had greater total energy intake and increased WAT and BAT stores. Body surface temperature increased with total energy intake and with protein, fat, and carbohydrate, making similar contributions per kJ ingested. Expression of three key regulators of thermogenesis were downregulated in BAT in mice on the lowest P:C diet. Conclusions: Low-protein diets induced sustained hyperphagia and a generalized expansion of fat stores. Increased body surface temperature on low P:C diets was consistent with diet-induced thermogenesis (DIT) as a means to dissipate excess ingested energy on such diets, although this was not sufficient to prevent development of increased adiposity. Whether BAT was involved in DIT is not clear. Increased BAT mass on low P:C diets might suggest so, but patterns of thermogenic gene expression do not support a role for BAT in DIT, although they might reflect failure of thermogenic function with prolonged exposure to a low P:C diet.
Endocrinology, 2006
The contribution of the caudal brainstem to adaptation to starvation was tested using chronically maintained decerebrate (CD) and neurologically intact controls. All rats were gavage fed an amount of diet that maintained weight gain in controls. CD rats were subjected to a two-stage surgery to produce a complete transection of the neuroaxis at the mesodiencephalic juncture. One week later, the rats were housed in an indirect calorimeter, and 24 h energy expenditure was measured for 4 d. One half of each of the CD and control groups was then starved for 48 h. Fed CD rats maintained a lower body temperature (35 C), a similar energy expenditure per unit fat-free mass but an elevated respiratory quotient compared with controls. They gained less weight, had 20% less lean tissue, and had 60% more fat than controls. Circulating leptin, adiponectin, and insulin were elevated, glucose was normal, but testosterone was dramatically reduced. Responses to starvation were similar in CD and controls; they reduced energy expenditure, decreased respiratory quotient, indicating lipid utilization, defended body temperature, mobilized fat, decreased serum leptin and insulin, and regulated plasma glucose. These data clearly demonstrate that the isolated caudal brainstem is sufficient to mediate many aspects of the energetic response to starvation. In intact animals, these responses may be refined by a contribution by more rostral brain areas or by communication between fore-and hind-brain. In the absence of communication from the forebrain, the caudal brainstem is inadequate for maintenance of testosterone levels or lean tissue in fed or fasted animals.
Integration of body temperature into the analysis of energy expenditure in the mouse
Molecular Metabolism, 2015
Objectives: We quantified the effect of environmental temperature on mouse energy homeostasis and body temperature. Methods: The effect of environmental temperature (4e33 C) on body temperature, energy expenditure, physical activity, and food intake in various mice (chow diet, high-fat diet, Brs3-/y , lipodystrophic) was measured using continuous monitoring. Results: Body temperature depended most on circadian phase and physical activity, but also on environmental temperature. The amounts of energy expenditure due to basal metabolic rate (calculated via a novel method), thermic effect of food, physical activity, and cold-induced thermogenesis were determined as a function of environmental temperature. The measured resting defended body temperature matched that calculated from the energy expenditure using Fourier's law of heat conduction. Mice defended a higher body temperature during physical activity. The cost of the warmer body temperature during the active phase is 4e16% of total daily energy expenditure. Parameters measured in diet-induced obese and Brs3-/y mice were similar to controls. The high post-mortem heat conductance demonstrates that most insulation in mice is via physiological mechanisms. Conclusions: At 22 C, cold-induced thermogenesis is w120% of basal metabolic rate. The higher body temperature during physical activity is due to a higher set point, not simply increased heat generation during exercise. Most insulation in mice is via physiological mechanisms, with little from fur or fat. Our analysis suggests that the definition of the upper limit of the thermoneutral zone should be reconsidered. Measuring body temperature informs interpretation of energy expenditure data and improves the predictiveness and utility of the mouse to model human energy homeostasis.
Estimating energy expenditure in mice using an energy balance technique
International journal of obesity (2005), 2013
To compare, in mice, the accuracy of estimates of energy expenditure (EE) using an energy balance technique (TEEbal: food energy intake and body composition change) vs indirect calorimetry (TEEIC). In 32 male C57BL/6J mice, EE was estimated using an energy balance (caloric intake minus change in body energy stores) method over a 37-day period. EE was also measured in the same animals by indirect calorimetry. These measures were compared. The two methods were highly correlated (r(2)=0.87: TEEbal=1.07*TEEIC-0.22, P<0.0001). By Bland-Altman analysis, TEEbal estimates were slightly higher (4.6±1.5%; P<0.05) than TEEIC estimates (Bias=0.55 kcal per 24 h). TEEbal can be performed in 'home cages' and provides an accurate integrated long-term measurement of EE while minimizing potentially confounding stress that may accompany the use of indirect calorimetry systems. The technique can also be used to assess long-term energy intake.
PLoS ONE, 2011
The mouse is an important model organism for investigating the molecular mechanisms of body weight regulation, but a quantitative understanding of mouse energy metabolism remains lacking. Therefore, we created a mathematical model of mouse energy metabolism to predict dynamic changes of body weight, body fat, energy expenditure, and metabolic fuel selection. Based on the principle of energy balance, we constructed ordinary differential equations representing the dynamics of body fat mass (FM) and fat-free mass (FFM) as a function of dietary intake and energy expenditure (EE). The EE model included the cost of tissue deposition, physical activity, diet-induced thermogenesis, and the influence of FM and FFM on metabolic rate. The model was calibrated using previously published data and validated by comparing its predictions to measurements in five groups of male C57/BL6 mice (N = 30) provided ad libitum access to either chow or high fat diets for varying time periods. The mathematical model accurately predicted the observed body weight and FM changes. Physical activity was predicted to decrease immediately upon switching from the chow to the high fat diet and the model coefficients relating EE to FM and FFM agreed with previous independent estimates. Metabolic fuel selection was predicted to depend on a complex interplay between diet composition, the degree of energy imbalance, and body composition. This is the first validated mathematical model of mouse energy metabolism and it provides a quantitative framework for investigating energy balance relationships in mouse models of obesity and diabetes.