Cushioned versus noncushioned centrifugation: sperm recovery rate and integrity

It was hypothesized that optimal sperm recovery rate (RR) without damage to the sperm would be obtained after centrifugation without a cushion solution. Semen collected three times from six light breed stallions was extended to 25 × 10(6) sperm/mL and centrifuged at CON (noncentrifuged), 900NC (no-cushion), 900C (cushion), 1800NC, and 1800C × g for 10 minutes. Sperm concentration, motility (TM and PM), and intact plasma membranes (PLM) and acrosomes (ACR) pre- and postcentrifugation (D0) and after 24 hours (D1) of cooling were evaluated. The RR in the CON (100 ± 0.0), 900NC (93.7 ± 2.9), and 1800NC (96.7 ± 2.6) groups was significantly higher than the 900C (68.7 ± 4.6) and 1800C (79.6 ± 3.5) groups. The D0 TM and PM were not different between the CON, 900NC, 900C, and 1800C, but were lower for the 1800NC group. The D1 TM and PM of the 900NC (75.2 ± 3.8 and 71.1 ± 4.1) and 900C (76.2 ± 3.7 and 72.4 ± 4.0) groups were significantly higher than the 1800NC (71.7 ± 4.1 and 67.3 ± 4.4) and 1800C (71.6 ± 4.1 and 67.2 ± 4.4) groups, and the CON (66.2 ± 4.5 and 60.0 ± 4.8) group was significantly lower than the other groups. The D1 PLM of the CON, 900NC, 900C, 1800NC, and 1800C groups were not different. The ACR on D1 was significantly lower for the CON (93.0 ± 2.4) group compared with all other groups. Optimal RR preserving sperm integrity was obtained in the 900NC group.