Aim and Background: Silver nano particles(NPs) or nanosilver (NS) are clusters of silver atoms that range in diameter from 1 to 100nm and are attracting interest as antibacterial and antimicrobial agents of applications in medicine.Resistance to antimicrobial agents by pathogenic bacteria has emerged in recent years and is a major reason for replacing of antibiotics with nano silver, but yet nanoparticle hazardous and toxic effects have not been studied extensively.

Materials and Methods: One of the agent of semen extenders is antibiotics. We replaced antibiotics with nano silver and investigated mobility, progressive of sperm . also result of nano silver on the growth of semen's bacteria was studied and them was compared with penicillin and streptomycin in similar conditions.

  Semen was diluted with citrate sodium, Yolk extender and was divided into nine portions. The control(sham) semen extender solution contained extended semen and no antibiotic and nanosilver, whereas streptomycin and penicillin solutions contained extended semen plus 1.0 mg/mL of streptomycin and penicillin. Also semen was diluted with Citrate sodium, Yolk extender supplemented with different concentrations of silver nano particle .

  Here, the effects of different concentration of silver NPs on bull sperm at frequent times after1, 3 hours was evaluated. Results: Mean percentages of motile and progressively motile sperm did not differ significantly among control(sham) and antibiotic and nanosilver -containing solutions after 1 hour. but after 3 hour, nanosilver was cytotoxic on bull sperm cells in more than 0.1mL concentration .(p<0.001)

  Control extended semen samples from ejaculates of bulls were contaminated with gram pasitive bacteria. Samples of antibiotic and concentration of 0.005mL , 0.01mL nanosilver had growth a few of bacteria.

Conclusion: Nanosilver has good antibacterial properties in semen extender in more than 0.05mL concentration . It can be suggested that antibiotics may be replaced with nano silver as antimicrobial agent in semen extenders in Some few concentration.