Thanks for asking to healthcaremagic.I understand your concern. Brief answer:Yes,might help improve the semen quantity. Detailed answer:I believe,the drug levofloxacin has been prescribed by your doctor empirically to treat chronic bacterial prostatitis/Urinary tract infection(like urethritis) which might be the reasons for reduced semen quantity in the ejaculate .However I would advise you to consult with your doctor (preferably an urologist) who can examine,assess the condition of prostate,seminal vesicles and to rule out any ejaculatory duct obstruction with few investigations like trans rectal ultrasound and direct you in the right path.Hope this information helps you.