IGF-1 outperforms vitamin E and crocin in improving semen quality, antioxidant profile and fertility gene expression in cryopreserved goat (Capra hircus) semen

Semen cryopreservation combined with artificial insemination (AI) benefits germplasm conservation, production, and breeding. Sperm cells are vulnerable to oxidative and other stressors during cryopreservation, necessitating the use of additives/antioxidants to mitigate this damage. This study aimed to evaluate the effects of vitamin E, IGF-1, and crocin supplementation on the quality of cryopreserved goat semen. A total of 48 pooled ejaculates from six goat bucks were diluted in Tris-Citrate-Fructose-Egg Yolk-Glycerol (TCFEYG) extender and divided into four groups: a control group (no antioxidant addition) and groups supplemented with 2 mM vitamin E, 125 ng/mL IGF-1 and 1 mM crocin. The semen samples were cryopreserved in liquid nitrogen (LN2) and analyzed post-thaw for sperm quality attributes, antioxidant enzyme activities and mRNA expression levels. IGF-1 supplementation significantly (P < 0.05) enhanced in vitro sperm quality, and antioxidant enzyme viz., catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S transferase (GST) and superoxide dismutase (SOD) compared to other treatments. Lipid peroxidation (LPO) levels were significantly (P < 0.05) lower, and fertility-related mRNA transcripts (NFE2L2, GPx4, CAT, and SOD2) were significantly (P < 0.05) upregulated in the IGF-1 group. No significant (P > 0.05) differences in pregnancy rates were observed among treatments after AI. In conclusion, IGF-1 supplementation significantly improved the post-thaw quality of cryopreserved goat semen, enhancing antioxidant activity and fertility- related mRNA expression compared to vitamin E and crocin treatments.