Efeitos de dieta hiperproteica contendo proteína do soro do leite associada ou não ao treinamento físico resistido em ratos

Abstract

The effects of high-protein diet (HD) administration, associated or not to resistance training (RT), are little-known. The present study verified the effects of the HD administration containing whey protein isolate (WPI) and of the resistance training (RT) performed on ladder on the biochemical and hematological parameters as well as on the animal´s performance. Thirty-two male Wistar rats, 45 days old (at the beginning of the experiment), were divided into four groups (n=8/group): normal protein diet sedentary (NS) and trained (NT); high-protein diet sedentary (HS) and trained (HT). NS and NT received a diet with 14% of WPI, while HS and HT received 35% of WPI. TR consisted in 8 climbs/3x week, during 6 weeks. At the 1th and 2nd weeks, the rats carried out a load of 70% of the maximal load determined by maximal load test (MLT), performed at the first and last days of training. The load was adjusted each 2 weeks for 80% and 85% of the MLT, respectively. After 12h of fasting, the rats were anesthetized and euthanized. Quadriceps (Q), anterior tibial (AT), gastrocnemius (G), soleus and long finger extensor, kidneys, liver and heart tissues were excised and weighed. The performance (g) showed to be improved in the last MLT in HT (964,8±117,6) compared to the other groups (HS: 730,6±89,7; NT: 472,6±72,7 and NS: 323,0±63,7). There was no difference in plasma levels of testosterone, insulin-like growth factor-1, hepatic enzymes, creatinine and β-hydroxybutyrate. Blood glucose (mg/dL) was lower in HT (151±21) if compared to NT (176±22), being similar to NS (165±14) and HS (155±16), respectively. The urea concentration (mg/dL) was higher in HT (57±7,1) when compared to NT (38±6,1) and NS (45±4,7), but similar to HS (53±7,1).Total cholesterol levels were significantly lower in HS (145,90±52,62) when compared to NT (200,00±31,92), NS (202,60±29,21), and HT (237,40±34,00). HDL-c levels were greater in NT (100,80±21,20) and HT (104,5±26,05) compared to NS (73,96±15,70) and HS (60,86±12,03). LDL-c levels were significantly lower in HS (70,64±47,65) when compared to NS (115,3±20,19) and HT (116,40±22,41). There was no difference in VLDL-c levels and triacylglycerols between groups. The kidney weight (g) was higher in HS (0,72±0,05) and HT (0,70±0,04) if compared to NS (0,58±0,04) and NT (0,59±0,02). The liver weight (g) was higher in HT (2,93±0,21) compared to NS (2,62±0,19) and NT (0,59±0,02). The heart weight (g) was higher in HS (0,32±0,02) in relation to NS (0,28±0,02) and NT (0,27±0,01). There was difference in G and Q weights (g), being HT (1,16±0,09; 1,67±0,09) higher in comparison to NT (1,04±0,08; 1,53±0,09), respectively. The association between RT and HD containing WPI improved the performance of animals as well as increased the weight of muscles and organs; there was no significant change in the biochemical and tissue parameters and the animals remained healthy (proven by hematological values) throughout the experiment.