Figure 1.
Oxylet Neonatal Indirect Calorimetry System.
To collect metabolic data, the Panlab Oxylet neonatal rodent indirect calorimetry system prototype was used in conjunction with associated apparati. The following components are identified: (A) LE 405 gas analyzer, (B) LE 400 Air Supply and Switching unit, (C) 215 ml metabolic chamber with bedding material, (D) 10-gallon aquarium, (E) Plexiglas sheet over water-filled Pyrex pan, and (F) variable-control heating pad.
Figure 2.
The effect of sex on metabolic parameters.
Rats from small (SML), medium (MED) and large (LRG) litters were surveyed on alternate days from P2–P14 at an ambient temperature of 28°C. All data are expressed as means±SEM. No differences between groups were noted for (A) carbon dioxide production (VCO2), (B) oxygen consumption (VO2), (C) respiratory quotient (RQ), or (D) daily energy expenditure (EE).
Figure 3.
The effect of time of day (during the light phase) on metabolic parameters.
Rats from small (SML), medium (MED) and large (LRG) litters were surveyed on alternate days from P2–P14 at an ambient temperature of 28°C. All data are expressed as means±SEM. No differences between groups were noted for (A) carbon dioxide production (VCO2), (B) oxygen consumption (VO2), (C) respiratory quotient (RQ), or (D) daily energy expenditure (EE).
Figure 4.
The effect of litter size on growth outcomes.
Growth measures were collected for each rat subject used from small (SML), medium (MED) and large (LRG) litters at an ambient temperature of 28°C. All data are presented as means±SEM. Analysis of (A) body weight, (B) snout-to-rump (SR) length, and (C) snout-to-occiput (SO) length data revealed that rats from the SML litter showed the greatest increases in growth from P2–P14. Days in which significant differences existed between groups are noted by asterisks.
Table 1.
Mean Growth, Metabolic, and Activity Data for Experiment 1.
Figure 5.
The effect of litter size on metabolic outcomes.
Metabolic parameters from each rat subject in small (SML), medium (MED) and large (LRG) litters were surveyed on alternate days from P2–P14 at an ambient temperature of 28°C. All data are expressed as means±SEM. No differences between groups were noted for (A) carbon dioxide production (VCO2), (B) oxygen consumption (VO2), or (D) daily energy expenditure (EE). Differences between groups were observed for (C) respiratory quotient (RQ), with rats from the SML litter having lower RQ's than rats from the other litters. Days in which significant differences existed between groups are noted by asterisks.
Figure 6.
The effect of ambient temperature on metabolic outcomes.
Metabolic parameters from each rat subject tested at ambient temperatures of 25°C, 30°C, and 34°C were surveyed on alternate days from P2–P6. All data are expressed as means±SEM. Differences between groups were observed for (A) carbon dioxide production (VCO2), (B) oxygen consumption (VO2), (C) respiratory quotient (RQ), and (D) daily energy expenditure (EE). Rats tested at 25°C demonstrated the highest VCO2, VO2, and EE values, while rats tested at 34°C demonstrated the lowest values in the same parameters. Days in which significant differences existed between groups are noted by asterisks.