Feed restriction and a diet's caloric value: The influence on the aerobic and anaerobic capacity of rats

Background

The influence of feed restriction and different diet's caloric value on the aerobic and anaerobic capacity is unclear in the literature. Thus, the objectives of this study were to determine the possible influences of two diets with different caloric values and the influence of feed restriction on the aerobic (anaerobic threshold: AT) and anaerobic (time to exhaustion: Tlim) variables measured by a lactate minimum test (LM) in rats.

Methods

We used 40 adult Wistar rats. The animals were divided into four groups: ad libitum commercial Purina^? diet (3028.0 Kcal/kg) (ALP), restricted commercial Purina^? diet (RAP), ad libitum semi-purified AIN-93 diet (3802.7 Kcal/kg) (ALD) and restricted semi-purified AIN-93 diet (RAD). The animals performed LM at the end of the experiment, 48 h before euthanasia. Comparisons between groups were performed by analysis of variance (p < 0,05).

Results

At the end of the experiment, the weights of the rats in the groups with the restricted diets were significantly lower than those in the groups with ad libitum diet intakes. In addition, the ALD group had higher amounts of adipose tissue. With respect to energetic substrates, the groups subjected to diet restriction had significantly higher levels of liver and muscle glycogen. There were no differences between the groups with respect to AT; however, the ALD group had lower lactatemia at the AT intensity and higher Tlim than the other groups.

Conclusions

We conclude that dietary restriction induces changes in energetic substrates and that ad libitum intake of a semi-purified AIN-93 diet results in an increase in adipose tissue, likely reducing the density of the animals in water and favouring their performance during the swimming exercises.     

Cu2+ Doped PVA Passivated ZnSe Nanoparticles-Preparation, Characterization and Properties

Cu²⁺ doped ZnSe nanoparticles are prepared by simple chemical method at room temperature with polyvinyl alcohol (PVA) as the passivating agent. The prepared sample is characterized by using X-ray diffraction, optical, photoluminescence, electron paramagnetic resonance (EPR) and FT-IR techniques. The average crystallite size is calculated from X-ray diffraction pattern and it is about 8 nm. The presence of the paramagnetic Cu²⁺ species in ZnSe is identified by optical and EPR measurements. The site symmetry for Cu²⁺ is ascribed as tetragonally distorted octahedral site symmetry. Crystal field, spin-Hamiltonian and bonding parameters are evaluated. Room temperature photoluminescence spectrum of Cu²⁺ doped ZnSe exhibits emission peaks at 343, 353 and 411 nm which corresponds to UV region at the excitation wavelength of 310 nm. FT-IR spectrum indicates the presence of various functional groups of PVA in ZnSe nanoparticles. Different physical parameters are also evaluated for the prepared sample.