Quality assessment of bovine cryopreserved sperm after sexing by flow cytometry and their use in in vitro embryo production

The objective was to evaluate the structural and functional quality of bull sperm after sexing by flow cytometry. Frozen non-sexed (NS), sexed for X (SX) and sexed for Y (SY) sperm from four bulls was used. Frozen-thawed sperm was analyzed for motility, sperm head agglutination, morphology, capacitation, and integrity of the plasma membrane, acrosome, and chromatin. After Percoll centrifugation (45:60% gradients), the pellet was used for sperm analysis or IVF. Data were analyzed using generalized linear models (P < 0.05) and were reported as least squares means ± standard error (SEM). Based on sperm evaluations, NS sperm had better (P < 0.05) quality than sexed sperm, including higher motility and greater percentages of cells with an intact membrane and acrosome (58.0 ± 3.0, 58.2 ± 3.0, and 60.9 ± 3.3) than SX (29.6 ± 1.3, 36.0 ± 2.9, and 37.1 ± 3.3), and SY (26.2 ± 2.1, 36.4 ± 2.9, and 37.5 ± 3.3). There were no differences (P > 0.05) among groups for fertilization and cleavage rates. Similarly, blastocyst rate on Day 8 (Day 0 = day of insemination) did not differ among groups (22.2 ± 3.2, 18.1 ± 3.3, and 14.8 ± 2.9 for NS, SX, and SY, respectively). Regarding embryo development kinetics, all groups had similar developmental stages from Days 6 to 9. Although the sex-sorting procedure affected sperm characteristics, it did not significantly affect fertilization or embryo development.