Exercise training at MLSS decreases weight gain and increases aerobic capacity in obese Zucker rats.

This study aimed to identify the aerobic capacity enhancement and subsequent body weight (BW) status of obese Zucker rats (OZRs) after 4 weeks of treadmill running exercise at the maximal lactate steady state (MLSS). In addition to obese Zucker rats (OZRs), lean Wistar Kyoto rats (WKYs) were used, and both species were divided into control and exercise groups as follows: obese exercise (OZR-EX, n=5), obese control (OZR-CON, n=5), lean exercise (WKY-EX, n=5) and lean control (WKY-CON, n=5). The OZR and WKY exercise groups trained 5 days per week at 12.5 m.min-1 and 20 m.min-1, respectively. After 4 weeks of training, MLSS was ascertained to evaluate the animals' aerobic capacity using 3 different velocities (12.5, 15 and 17.5 m.min-1 for OZRs and 25, 30 and 35 m.min-1 for WKYs). The MLSS of OZR-EX was identified at the velocity of 15 m.min-1, representing a 20% increase in aerobic capacity after the exercise program. The MLSS of WKY-EX was identified at 30 m.min-1 with a 50% increase of in aerobic capacity. Obese animals that exercised showed reduced weight gain compared to the non-exercise obese control group (p <0.05). Our results thus show that exercise training at MLSS intensity increased the aerobic capacity in both obese and non-obese animals and also reduced BW gain.

Identification of a novel subtype of feline immunodeficiency virus in a population of naturally infected felines in the Brazilian Federal District.

The feline immunodeficiency virus (FIV) is a retrovirus that is found worldwide, and it can be assigned to six subtypes (A, B, C, D, E, and a putative subtype F) based on sequencing analysis of the env and gag genes. Subtypes A and B are the most common worldwide. In Brazil, several authors have isolated only subtype B, and its prevalence differs markedly among investigated populations. Blood samples from 200 domestic felines from the Federal District in Brazil were analyzed by PCR. Samples that tested positive for FIV were then cloned, sequenced, and analyzed phylogenetically and statistically. The results represent the first description of FIV infection in the Central Region of Brazil and suggest that only 2 % of felines in this region are positive for the virus. In addition, the analysis showed that one out of the four positive samples that we detected could not be assigned to any of the six classical subtypes. This sample was taken as a putative novel subtype of the FIV virus. The remaining three positive samples were assigned to subtype B, with differences existing among these samples.

Determination of the maximal lactate steady state in obese Zucker rats.

This study aims to identify the maximum lactate steady state (MLSS) in obese rats in order to provide a more effective tool in the exercise training prescription for this important animal model. To make such determination, obese (Zucker, n=5) (390.0±18.8 g) and lean (Wistar, n=5) (227.3±26.2 g) rats were studied. After adaptation of animals to treadmill, the MLSS was determined by using 3 different velocities (10 m.min⁻¹, 12.5 m.min⁻¹ and 15 m.min⁻¹ for Zucker and 15 m.min⁻¹, 20 m.min⁻¹ and 25 m.min⁻¹ for Wistar). The MLSS was defined as the highest blood lactate concentration that increased up to 1 mmol.L⁻¹ during constant exercise. In obese rats, the MLSS was found in a velocity considerably lower than in lean controls (12.5 m.min⁻¹ and 20 m.min⁻¹), respectively (p<0.05). Therefore, the identification of MLSS in obese Zucker rats is an important tool for exercise prescription and evaluation in obese rat models.