Motility (mean±SD) after thawing of X. helleri sperm cryopreserved with 14% glycerol alone (open circles), and 14% glycerol combined with fetal bovine serum at 5% (open triangles), 10% (open squares), 15% (filled circles), and 20% (filled triangles), and centrifuged at 1000 ×g for 10 min at 4 °C with the removal of supernatant, and replacement of fresh HBSS. Motility was monitored at 2, 18, 42, 66, 90, 138, 182, and 230 h after centrifugation.