Semen quality, antioxidant status and reproductive performance of rabbits bucks fed milk thistle seeds and rosemary leaves

•A study on natural antioxidants on rabbit semen quality is proposed.•Milk thistle seeds and rosemary leaves were added at different levels in rabbit diet.•Rosemary leaves at 5 g/kg diet improved semen quality and fertility.•Milk thistle at 10 g/kg improved semen quality, fertility and economic efficiency.

The study aimed to investigate the effects of milk thistle seeds (MTS) and rosemary leaves (RL) both at 5 and 10 g/kg diet on reproductive performance, semen quality and blood metabolites of rabbit bucks. A total of 35 rabbit bucks were randomly distributed into five experimental groups (7 bucks/group). All the groups were fed the same basal diet. The 1st group (control) did not have MTS and RL in its basal diet. The 2nd and 3rd groups were supplemented with MTS at 5 and 10 g/kg, respectively. The 4th and 5th groups were fed the basal diet supplemented with RL at 5 and 10 g/kg, respectively. The sperm concentration (SC), total sperm output (TSO), live sperm (LS), total live sperm (TLS) and total motile sperm (TMS) were significantly greater in the bucks fed MTS at 10 and RL at 5 g/kg diet than the control group. Bucks fed MTS at 10 g/kg diet had higher fertility than the control. Also, RL 5 g/kg group showed higher testosterone and fertility than the control, but the MTS 10 g/kg group showed the highest value for both parameters. In conclusion, MTS and RL at 10 and 5 g/kg, respectively, significantly improved the semen quality and the fertility and MTS also increased the economic efficiency of rabbit bucks.