Effects of sex-sorted spermatozoa on the efficiency of in vitro fertilization and ultrastructure of in vitro produced bovine blastocysts

Frozen-thawed sexed semen from six bulls (Holstein) was used for studying their efficiency in an in vitro fertilization (IVF)-programme and to compare their ultrastructure with in vitro produced bovine blastocysts produced with non-sorted sperm. Progressive motility of sorted spermatozoa, their IVF rate, development of produced blastocysts and the ultrastructure of the blastocysts were analysed. The cleavage rates of sexed sperm of bulls (groups S1, S2 and S4) were significantly lower than that of unsorted control sperm (P 0.05). The remaining five sexed sperm groups resulted in significantly lower developmental rates of blastocysts on day 7 (S1, 4.9%; S2, 0%; S3, 0%, S4, 3.5%; S6, 25.8%, P 0.70), the regression parameter was significant (P < 0.01). Furthermore, with a straw containing 10 × 106 sexed spermatozoa significantly lower number oocytes was fertilized than with the same concentration of non-sexed sperm (P < 0.01). Our results demonstrate that the suitability of sperm sorting for in vitro fertilization (IVF) is lower than no sexed sperm. Our ultrastructural studies showed that blastocysts produced with flow-cytometrically sex-sorted spermatozoa possessed deviations in the number and structure of organelles like mitochondria, rough endoplasmic reticulum (ER) and nuclear envelope. These morphological alterations may be responsible for compromised development that observed in embryos produced with sex-sorted spermatozoa. Thus, we conclude that sperm sex sorting can markedly affect the efficiency of an IVF-programme.Fil: Palma, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Embryo Tech S.A.; Uruguay. Reprobiotec; ArgentinaFil: Olivier, N. S.. Embryo Tech S.A.; UruguayFil: Neumüller, Ch.. Reprobiotec; ArgentinaFil: Sinowatz, F.. University of Munich; Alemani