Efeitos de dieta hiperproteica contendo proteína isolada do soro do leite em ratos submetidos ao treinamento resistido de saltos na água

Abstract

Changes in the proportions and types of macronutrients alter metabolic processes, such as energy generation and heat dissipation. High protein diets (HD) with reduced amount of carbohydrate, associated or not to the resistancetraining (RT), are known to reduce the body fat reserves, stimulate satiety, reduce body weight, in addition to promoting muscle hypertrophy.Due to the different amino acid composition, high digestibility and rapid absorption, whey protein isolate (WPI) can present enhanced action if compared to other protein sources.The present study has verified the effects of HDcontainingWPI on various blood parameters, food (FI) and water (HI)intakes,relative weight of organs, muscle and adipose tissue, morphological analysis of liver and muscle tissues, in addition to protein expression of GLUT-4 and p70s6k in gastrocnemius muscleof rats subjected to RT of aquatic jumps. Thirty-two male Wistar rats (60 days of age) were separated, randomly, into 4 groups (n = 8/group): Sedentary Normoproteic (WPI14%) (SN); Sedentary Hiperproteic (WPI35%) (SH); Trained Normoproteic (WPI14%) (NT), and Trained Hiperproteic (WPI35%) (HT).The RT was performed 5 x/wk and consisted of 4 x 10 jumps in the water (1 min between sets), with progressive load of 25 to 55% of body weight (BW), during 8 wk. The FI and HI as well as BW were registered 5 x/wk. After anesthesia and euthanasia, blood samples were collected and centrifuged to obtain serum in order to determine biochemical and hormonal parameters, followed by median laparotomy with excision for determining the weights of the heart, kidneys, gastrocnemius and soleus muscles and perirenal, omental, epididymal and subcutaneous inguinal fat tissues.For morphological analysis, portions of the liver and muscles have been immersed in OCT solution, frozen in isopentane and stained with HE.A gastrocnemius portion was used for the determination of protein expression of GLUT-4 and p70s6k by western blotting assay. A) FI (g/100 g) (p < 0.001) and BW (g) (p < 0.01) were higher in SN when compared to SH, TH and NT. B) Relative weight of tissue/organ (g): perirenal and retroperitoneal adipose tissues were lower (p < 0.01) in SH and TH compared to SN (no difference to TN); omental and subcutaneous adipose tissues were higher (p < 0.03) in SNif compared to SH.The epididymal adipose tissue was higher (p < 0.01) in SN when compared to other groups.The heart was higher (p < 0.01) inTHif compared toTN and SN, without difference to SH; Kidneys and liver (g) were higher (p < 0.001) in TH and SH when compared to SN and TN; gastrocnemius was lower (p = 0.04) in SN if compared to other groups; soleus was higher (p < 0.001) in SH in relation to other groups.C) Biochemical parameters (mg/dL): the concentration of triglycerides was reduced (p = 0.03) in the TH groups compared to SH, TN and SN.D) Hormonal parameters: there were no changes in the concentrations of adiponectin and leptin. E) Molecular parameters: there was no change in the protein expression of GLUT-4 and p70s6k .HD containingWPIimproved body composition (i.e. reduced fatty deposits), increased the weight of the heart, kidneys, liver and gastrocnemius and soleus muscles; However, this kind of diet maintained normal the histomorphology of muscle and liver and, when associated RT, reduced the serum levels of triglycerides.Such results, especially those related to deposits of fat can be attributed, at least in part, to the increase of the thermogenesis induced by higher protein metabolism by these organs, being this via ineffective in providing chemical energy (ATP) culminating, thus, in higher lipolysis without tissue and/or organic injuries occurrence. In addition, this hypothesis is strengthened by the fact that the biochemical markers remained unchanged at the end of the experimental period.