Spirulina (Arthrospira platensis) extract promotes motility, microscopic, and antioxidative parameters of ram semen during refrigerated storage

Abstract

This study investigated the effect of spirulina ethanolic extract (SEE) on the quality of ram semen during low-temperature liquid storage and the relationship between sperm features. Ejaculates were collected from five Djallonké rams, pooled, extended with Tris-egg yolk (TEY) enriched with 0 (control), 20 (SEE20), 40 (SEE40), and 80 µg/mL (SEE80) of SEE to reach the concentration of 200 × 106 spz/mL, and stored at 4°C for 72 h. Extended semen samples were assessed for total motility, progressive motility, sperm motion characteristics, viability, membrane integrity, and morphology at 6, 24, 48 and 72 h of storage. Moreover, malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase, (SOD) and catalase (CAT) levels were measured at 72 h of storage. The enrichment of TEY with SEE at 40 and 80 µg/mL, improved sperm total motility at 48 and 72 h of storage (P < 0.05). Also, all SEE-treated samples evidenced higher progressive motility in comparison to the control at 48 and 72 h (P < 0.05). SEE80 group showed the highest percentages of viability (76.26 ± 0.90%) and membrane integrity (58.19 ± 1.50%); whereas, SEE40 demonstrated the lowest percentage of morphological abnormality (18.14 ± 1.01%) at 72 h of storage. SEE did not influence NO levels; however, at 40 µg/mL, it reduced MDA concentration and improved SOD and CAT activities (P < 0.05). Total motility was positively correlated to progressive motility (r = 0.69, P < 0.01), viability (r = 0.91, P < 0.01), and membrane integrity (r = 0.49, P < 0.05); while, morphological abnormality was negatively correlated to the other sperm parameters. Furthermore, MDA was negatively correlated to total motility (r = - 0.91, P < 0.01), progressive motility (r = -0.70, P < 0.01), and viability (r = -0.91, P < 0.01), and positively correlated to morphological abnormality (r = 0.70, P < 0.01). An entirely opposite figure was recorded for SOD. Overall, the results indicated that SEE, especially at 40 µg/mL, can protect ram semen against liquid storage-associated damages. Furthermore, positive and negative correlations exist between semen parameters.