Abstract
Background:
One native goat species in Indonesia that faces extinction because of cross-breeding is the Kacang goat (Capra hircus). In addition to ensuring food security as a meat-producing livestock, artificial insemination of the Kacang goat could simultaneously conserve it and improve its genetic quality.

Aim:
The purpose of this study was to investigate the effect of the addition of epigallocatechin-3-gallate nanoparticles (EGCG) to skimmed egg yolk (SM-EY) extender on the quality of post-thawed Kacang buck spermatozoa for artificial insemination.

Methods:
Fresh semen of Kacang buck was diluted in SM-EY without (T0) and with the addition of 50 or 100 mg EGCG/dl extender for T1 and T2, respectively. Extended semen was frozen in liquid nitrogen (−196°C) for a week in French tiny straws with 60 million spermatozoa per straw, following a standard protocol. Six thawed replicates from each group were tested for sperm motility, viability, intact plasma membrane (IPM), malonaldehyde (MDA), DNA integrity, and chromatin density.

Results:
Pre-equilibration sperm motility, viability, and IPM were not significantly different among the groups (p > 0.05). Post-equilibration sperm motility, viability, and IPM were higher (p < 0.05) in the EGCG group than in the control group. In post-thawed semen, the EGCG groups showed higher sperm motility, viability, IPM, and DNA integrity and lower MDA levels (p < 0.05) than the control group. The chromatin density did not differ between the groups (p > 0.05).

Conclusion:
The addition of 50 or 100 mg EGCG/dl SM-EY extender significantly improved the post-thawed spermatozoa quality of Kacang buck.

Key words: Food security, DNA integrity, Extinction risk, Sperm viability, Sperm motility