Study question
Are there any differences between the effect of each member of the branched-chain amino acids (BCAAs) on sperm parameters and plasma amino acids profile?
Summary answer
Valine supplementation had destructive effects on sperm parameters and viability. However, blood amino acids profile were similar among treatments.
What is known already
BCAAs, a group of three essential amino acids, have a crucial role on protein synthesis, besides being strongly associated with impaired glucose and fat metabolism. Although BCAAs supplements are one of the most demanding products for the fitness industry to increase the lean body mass and boost exercise performance, little information exists on the advantages and disadvantages of dietary BCAAs on male fertility.
Study design, size, duration
Fifty NMRI mature male mice were divided into five groups and were fed diets as follow: Control (CTR): 2.4% Beta-alanine, Leucine (Leu): 1.18% Leu + 1.2% Beta-alanine, Isoleucine (Ile): 0.58% Ile + 1.8% Beta-alanine, Valine (Val): 0.65% + 1.7% Beta-alanine, and BCAAs (Leu:Ile:Val ratio of 2:1:1): 2.4% BCAA: 1.18% Leu + 0.58% Ile + 0.65% Val. After 5 weeks, testes and epididymides were dissected, and sperm parameters and plasma amino acids profile were assessed.
Participants/materials, setting, methods
Semen parameters were evaluated by a Computer-Aided Semen Analysis (CASA) system. Plasma amino acids concentrations were determined by HPLC. Data were analyzed using SPSS and statistical differences among various groups were determined by ANOVA and Tukey’s post-hoc test.
Main results and the role of chance
Higher BCAAs intake, particularly Val, increased the destructive mechanisms on sperm viability. The results showed no significant difference on body weight after 40 days. Sperm concentration (8.4 vs. 4.5 ×106), progressive motility (51.5 vs. 27.2 %), and viability (67 vs. 56 % for CTR and Val group, respectively) decreased dominantly in the Val group compared to CTR (p≤0.05). The immotile parameter was significantly higher in the Val group compared to the CTR (p≤0.05). In addition, there were no significant differences on plasma amino acids profile.
Limitations, reasons for caution
The current study's limitation is that only one level of BCAAs was used. Given the potential role of Val on sperm cell death, further data on different levels of all BCAAs, especially Val administration and evaluation of the related mechanisms are needed.
Wider implications of the findings
The findings of our study show, for the first time, that individual levels of Ile and Leu have different effects on sperm parameters compared with all BCAAs or Val. More attention should be given to BCAAs supplementation and semen quality that was previously ignored.
Trial registration number
not applicable