RESUMO
This study aimed to evaluate the effects of protein-restricted (PR) and energy restriction (ER) on male repro-ductive function. Eighteen weaning Wistar rats were divided into three groups, and were fed an experimental diet for five months. The first group, a control (C), received a diet containing 20% casein and 1.7×106 J/kg diet. The ER was given 50% less calories vs. C, while the PR group was given a low-protein diet (10% casein). The reproductive function was evaluated on serum and testis using anthropometrical, histological, hormonal, and oxidative parameters. The body weight was reduced by 37% and 40%, respectively, in the PR and ER groups vs. C. In the PR group, the testis relative weight was decreased, whereas that of the seminal vesicles was higher than that of C. The epididymis and prostate relative weights remained unchanged in the three experimental groups. Furthermore, serum testosterone concentrations were respectively 1.4- and 2.8-fold lower in the PR and ER groups vs. C, whereas no significant difference was found in luteinizing hormone and follicle-stimulating hormone levels among the groups. Compared with the C group, thiobarbituric acid reactive substance, carbonyl levels, glutathione, and glutathione reductase activity reduced significantly in PR, and specifically in ER rat's testis, whereas, catalase and superoxide dismutase activities increased. Furthermore, the testis and epididymis examination revealed histological alterations in the PR and ER groups. In conclusion, ER and PR diets could reduce the oxidant markers, even though they may alter the reproductive activity by probably altering testosterone production.