Adding chitosan nanoparticles of green tea extract in diluent and thawing temperatures ameliorate the post-thawed quality of Boer buck semen

To improve the quality of post-thawing Boer buck semen for artificial insemination by adding green tea extract chitosan nanoparticles to skimmed egg yolk diluent, and the proper thawing temperature. The ejaculate of Boer buck was added to skimmed egg yolk diluent without (the control group) and with adding 1 μg of chitosan nanoparticles of green tea extract per mL of diluent (the treatment group). Then, the diluted semen was filled in French mini straws containing 60× 106 live sperm per straw, frozen in a standard protocol, and stored as frozen semen at -196 °C for a week. Six replicates from each group were diluted for 30 s at 37 °C or 39 °C sterile water to evaluate the semen quality. Post-thawing (at 37 °C or 39 °C) of live sperm, progressive motility, and plasma membrane integrity were lower compared to those of the pre-freezing stage (P<0.05). Thawing at 37 °C resulted in no significant difference in live sperm, progressive motility, and plasma membrane between the control group and the treatment group (P>0.05). The live sperm, progressive motility, and plasma membrane of the treatment group in the pre-freezing stage, and post-thawed at 39 C were higher compared to those of the control group (P<0.05). There was no significant difference in malondialdehyde (MDA) concentration, DNA fragmentation, and catalase concentration of thawing at 37 °C compared to those of 39 °C in the same group. The MDA concentration and DNA fragmentation in thawing at 37 °C and 39 °C of the treatment group were significantly lower than those of the control group (P<0.05). However, the catalase concentration in thawing at 37 °C and 39 °C of the treatment group was not significantly different than the control group (P>0.05). Higher quality post-thawing Boer buck semen is achieved by adding 1 μg/mL of chitosan nanoparticles of green tea extract to the skimmed egg yolk diluent and thawing at 39 °C.