Effect of nano-spirulina (Spirulina platensis) supplementation to tris egg yolk extender on CASA motility and functional quality of cryopreserved Zaraibi goat sperm.

Cryopreservation plays an essential role in artificial insemination programs and germplasm banking; however, it exposes the sperm cell to oxidative stress, leading to lipid peroxidation with a decline in sperm fertilizing capacity. The current study examined the effects of supplementing Zaraibi goats' semen extender with spirulina nanoparticles (SNPs) on post-thaw semen quality. Four fertile bucks' ejaculates were collected, pooled, and diluted using tris-egg yolk extender supplemented with 0, 10, 25, or 50 µg/mL of SNPs. After being cooled down gradually, equilibrated, and frozen in liquid nitrogen, the samples were assessed for CASA-based motility, plasma membrane and acrosomal integrity, total antioxidant capacity (TAC), lipid peroxidation (malondialdehyde; MDA), and DNA integrity (comet assay). Supplementation with 25 µg/mL SNPs significantly improved total and progressive motility, plasma membrane integrity, and TAC, while reducing MDA concentration and DNA fragmentation compared to the control group (P < 0.05). Higher SNP concentrations (50 µg/mL) provided no added benefit and slightly decreased acrosomal integrity compared to the control and 25 µg/mL SNPs. These results indicate that nano-spirulina, especially at a concentration of 25 µg/mL, improves antioxidant defense and preserves sperm quality during goat semen cryopreservation, demonstrating its potential as a natural antioxidant additive in cryo-extender.