title: Effects of diets supplemented with branched-chain amino acids on the performance and fatigue mechanisms of rats submitted to prolonged physical exercise.
abstract: This study aimed to determine the effects of diets chronically supplemented with branched-chain amino acids (BCAA) on the fatigue mechanisms of trained rats. Thirty-six adult Wistar rats were trained for six weeks. The training protocol consisted of bouts of swimming exercise (one hour a day, five times a week, for six weeks). The animals received a control diet (C) (n = 12), a diet supplemented with 3.57% BCAA (S1) (n = 12), or a diet supplemented with 4.76% BCAA (S2) (n = 12). On the last day of the training protocol, half the animals in each group were sacrificed after one hour of swimming (1H), and the other half after a swimming exhaustion test (EX). Swimming time until exhaustion was increased by 37% in group S1 and reduced by 43% in group S2 compared to group C. Results indicate that the S1 diet had a beneficial effect on performance by sparing glycogen in the soleus muscle (p &lt; 0.05) and by inducing a lower concentration of plasma ammonia, whereas the S2 diet had a negative effect on performance due to hyperammonemia (p &lt; 0.05). The hypothalamic concentration of serotonin was not significantly different between the 1H and EX conditions. In conclusion, chronic BCAA supplementation led to increased performance in rats subjected to a swimming test to exhaustion. However, this is a dose-dependent effect, since chronic ingestion of elevated quantities of BCAA led to a reduction in performance.
authors.affiliation: Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo 05508900, Brazil. ginafalavigna@yahoo.com.br
authors.forename: Gina
authors.initials: G
authors.lastname: Falavigna
authors.forename: Jonas
authors.initials: J
authors.lastname: Alves de Araújo
authors.forename: Marcelo Macedo
authors.initials: MM
authors.lastname: Rogero
authors.forename: Ivanir Santana de Oliveira
authors.initials: IS
authors.lastname: Pires
authors.forename: Rogério Graça
authors.initials: RG
authors.lastname: Pedrosa
authors.forename: Eivor
authors.initials: E
authors.lastname: Martins
authors.forename: Inar
authors.initials: I
authors.lastname: Alves de Castro
authors.forename: Julio
authors.initials: J
authors.lastname: Tirapegui
mesh_terms: D000597:Amino Acids, Branched-Chain / Q000008:administration & dosage*; D000641:Ammonia / Q000097:blood; D000818:Animals; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005221:Fatigue; D006003:Glycogen / Q000032:analysis; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry; D010805:Physical Conditioning, Animal / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013550:Swimming
chemical_list: D000597:Amino Acids, Branched-Chain; D000641:Ammonia; D006003:Glycogen