The Use of Plant Extracts to Improve Male Reproductive Performance: A Review Focusing on Mammalian Semen Quality and Preservation

In African countries and many developing countries, communal farmers rely on livestock such as cattle, goats, and sheep to support food security, income, and agricultural activities. Fertility in these animals is often limited by poor semen quality, which reduces sperm concentration, total motility, and morphology. Assisted reproductive biotechnologies, including semen cryopreservation and artificial insemination, are increasingly essential to enhance reproductive efficiency and productivity. Although cryopreservation preserves valuable genetic material, it can damage sperm cells, making high-quality extenders critical for protection. Common extenders, such as Tris-egg yolk glucose, citrate-sugar-based, and skimmed milk solutions, supply nutrients and protect sperm membranes. To further minimize oxidative stress, antioxidants are incorporated, with growing interest in plant-derived compounds. Many plants contain bioactive substances, including antioxidants and phytomelatonin, which can enhance sperm quality safely and effectively. This review examines the use of plant-based antioxidants during semen cryopreservation and highlights their potential to improve fertility in mammalian livestock.