Introduction: Obesity and high fat diet (HFD) has side effects on male fertility. The aim of this study was to evaluate the effect of apple vinegar on spermatogenesis and serum total antioxidant status (TAS) in rats under HFD.

Methods: Twenty-four Wistar male rats were divided to three groups, including (n = 8): control, HFD, HFD + apple vinegar. The control group received 16.6 kcal/day and the other two groups received HFD containing 51.6 kcal/day. After 16 weeks, group 3 received 5% apple vinegar in drinking water orally for six weeks. At the end of the experiment, epididymis sperm parameters including: count, morphology and motility, were measured. Serum level of TAS, testosterone and estradiol was assayed with enzyme linked immunosorbent assay (ELISA). Testicular apoptosis was assayed with terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) and spermatogenesis was studied with quantitative histologic method. Statistical analysis was performed using analysis of variance (ANOVA) and Tukey’s test.

Results: Apple vinegar increased count and forward motility of sperms, when compared with HFD (P < 0.05). However, it was not effective on morphology. Numbers of apoptotic cells reduced in the vinegar-treated group (P < 0.001). Vinegar increased serum levels of testosterone and TAS compared with HFD (P < 0.05). However, estradiol level was not changed. Vinegar reduced the lee index, when compared with HFD (P < 0.001). The numbers of spermatogonia, primary pachytene and leptotene spermatocyte, and round spermatids were not changed. However, the numbers of elongated spermatids were increased compared with HFD (P < 0.05).

Conclusions: This study indicated that daily use of apple vinegar in rats under HFD for six weeks improved spermatogenesis through reduction of testis apoptosis, increasing serum TAS and testosterone.