Oxygen consumption of rats with broad intestinal resection

The study was performed to investigate possible alterations in oxygen consumption in an animal model with broad intestinal resection. Oxygen consumption and the thermal effect of a short meal were measured in rats subjected to short bowel syndrome. Four groups of rats were used. Group I was the control group, group II was sham operated, group III was submitted to 80 percent jejunum-ileum resection, and group IV was submitted to 80 percent jejunum-ileum resection with colon interposition. Ninety days after surgery, oxygen consumption was measured over a period of 6 h with the animals fasted overnight. The thermal effect of feeding was determined in another session of oxygen consumption measurement in animals fasted for 12 h. A 12-kcal meal was then introduced into the animal chamber and oxygen consumption was measured for a further 4 h. No differences in fasting oxygen consumption or in the thermal effect of the meal were detected among the groups studied. It is concluded that short bowel syndrome does not affect the overall energy expenditure of rats

Energy balance in subcutaneous melanoma-bearing mice

Energy balance of control and melanoma-bearing mice was determined after 15 days of controlled food intake. Body and tumor energy contents were evaluated after preparing the materials for bomb calorimetry. Neither energy intake nor expenditure was different between control and melanoma mice. Body energy gain was lower in melanoma mice, but including tumor energy both groups had similar energy gain during the experimental period. It is concluded that a two-week skin melanoma did not seriously affect the energy balance of mice, and that tumor growth was achieved by utilizing body energy without promoting any increase in energy intake.

Energy balance of rats subjected to continuous and intermittent food restriction

Data from our laboratory have demonstrated that food restriction leads to alterations in energy balance such as reduced energy expenditure as an energy conservation mechanism. Food restriction may be imposed on the animals in different ways. The most common is to give equal daily amounts of restricted food. Alternatively, food may be given once every two or three days so that the food intake is not constant with the animal tending to eat more on the first day and be very restricted during the subsequent days of period. The former model may elicit habituation to the low food intake-while the latter may decrease the habituatiuon stimulus since the food intake is not constant. Energy balance was determined in 3 groups of female rats weighing 206,7 + or - 2.0 g (N=6 each): control (C), which, received food ad libitum; continuosly food restricted (CR), which received 8 g of food daily, and intermittently food restricted (IR), which received 24 g of food every 3 days. On the 21st day of treatment, the animals from both food-restricted groups showed a similar reduction of body weight (-47,9 + or - 5,1 and -55.8 + or - 4.0 g for CR and IR, respectively) and body energy (-501.0 + or - 65.5 and -427.0 + or - 82.1 for CR and IR, respectively), and they had similar energy expenditure (2643 + or - 72 and 2518 + or - 97 for CR and IR, respectively) which was different from ad libitum controls (4.6 + or - 2.9 body weight gain, 277,3 + or - 42.5 body energy gain and 4574 + or - 290 energy expenditure). Body weight decreased continuously in the CR group while in the IR group it followed the pattern of food intake with up-and-down shifts. We conclude that the energy balance pattern presented by food restricted animals in the same regardless of the form of food restriction imposed

The effect of fasting and refeeding on oxygen consumption by rats

Oxygen consumption is usually measured on fasted animals to avoid the thermal effect of feeding. However, fasting itself may decrease oxyge consumption as a way of conserving energy. The present study was undertaken to determine how long the fasting period should be to avoid the thermal effect of feeding without promoting a further decrease in oxygen consumption by the activation of energy-conservation mechanisms. Oxygen consumption was also measured to evaluate the effect of refeeding after different fasting periods. There was a 16% decrease in oxygen consumption from 0 to 12 h fasting related to the thermal effect of feeding, followed by a less intense (12%) decrease from 12 to 48 h fasting resulting from the energy conservationn mechanism. During refeeding, oxygen consumption was higher during the first 30-min period than during the last 30-min period of the 1-h measurement, indicating the probable presence of a cephalic phase of postprandial thermogenesis. We conclude that 12-h fasting is the most appropriate period to avoid the thermal effect of feeding without significantly stimulating the energy conservation mechanism

Energy balance of pregnant rats

Energy balance of pregnant and non-pregnant female rats was determined after 20 days of gestation. Energy contents of male and female pups and placentae were also determined. The metabolizable energy intake of pregnant rats was 33% higher than that of non-pregnant controls. Body weight gain was 9.4-fold that of non-pregnant rats. Gains in energy was stored, probably for later use in an energy-requiring process such as lactation. Food was processed as expected in pregnant rats, since although gross food efficiency (gain in body energy divided by metabolizable energy intake) was greater in pregnant than in non-pregnant rats (5.4% vs 17.5%), only 53.7% of the extra energy intake was deposited in the dams