Protective Effects of Ginseng Extract Against Oxidative Stress in Chilled Rooster Semen: Implications for Sperm Quality and Fertility

Oxidative stress is a primary driver of sperm deterioration during chilled storage of poultry semen, and identifying effective natural antioxidant supplements for semen extenders is an important practical goal for poultry reproductive management. This study evaluated the protective effects of ginseng extract (Panax ginseng) supplementation on sperm viability, motility, oxidative stress biomarkers, antioxidant defense, and fertility in chilled Leung Hang Kao rooster semen. Pooled semen was diluted in IGGKPh extender supplemented with ginseng extract at 0, 1, 2, 3, or 4 mg/mL and stored at 5 °C for 0, 24, and 48 h. Sperm viability, total motility, progressive motility, malondialdehyde (MDA) concentration, total antioxidant capacity (T-AOC), glutathione peroxidase (GPx) activity, catalase (CAT) activity, and fertility following artificial insemination were evaluated at each time point. All ginseng-supplemented groups showed significantly lower MDA concentrations and higher GPx activity than the unsupplemented control throughout storage. At 48 h, total motility and progressive motility were highest in the 2 and 3 mg/mL groups, while T-AOC was best maintained in the 1 and 2 mg/mL groups. CAT activity did not differ significantly among groups at 48 h (p = 0.2498). Fertility was significantly higher in the 1 and 2 mg/mL groups than in the control after 24 and 48 h of storage, and the alignment between T-AOC and fertility across storage time points indicated that overall antioxidant buffering capacity was a stronger determinant of fertilizing competence than individual enzyme activities or MDA concentration alone. Concentrations of 3–4 mg/mL, despite producing lower MDA at 48 h, did not confer superior fertility outcomes, suggesting a hormetic dose–response relationship. Based on integrated evidence from sperm quality, antioxidant status, and in vivo fertility, ginseng extract supplementation at 1–2 mg/mL is recommended as the most suitable range for preserving chilled Leung Hang Kao rooster semen and may represent a practical natural antioxidant strategy for Thai native poultry breeding programs.