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Effects of bulls with different field fertility on in vitro embryo cleavage and development using sperm co-culture systems
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Theriogenology EFFECTS OF BULLS WITH DIFFERENT FIELD FERTILITY ON IN VITRO EMBRYO CLEAVAGE AND DEVELOPMENT USING SPERM CO-CULTURE SYSTEMS CS Schneider JE Ellington and RW Wright Jr. Department of Animal Sciences, Washington State University Pullman WA 99 164-6332
Development of an in vitro assay system to determine bull fertility would result in tremendous economic savings compared to expensive field fertility trials. The objectives of these experiments were to compare rates of in vitro fertilization and embryo development following oocyte exposure to sperm from bulls of known field fertility. Concomitantly, the effects of sperm co-culture systems using Bovine Oviductal Epithelial Cells (BOEC), Buffalo Rat Liver Cells (BRLC) or cell free cultures (Control) were examined. Semen from nine bulls (Select Sires Inc.) was classified, by 60-90 day nonreturn rates, as having either: high (n=3) 73.2k3.0, medium (s3) 70.3f1.9 or low (n=3) 65.8ti.7 field fertility. An initial experiment was performed to determine the optimal level of heparin needed to facilitate capacitation in the different bulls. Analysis of embryo cleavage rates indicated that addition of 10 IU of heparin to the fertilization media smliciently capacitated sperm from all bulls. In experiment II, a total of 1,321 oocytes were exposed to IVMAVF yielding .737 embryos 2 2 cell which developed into 343 embryos 2 compact morula. There was no difference in embryo cleavage rates between the high (57.5*18%), medium (56.8fi3%) and low (56.9+18%) fertility groups. Development to morula or beyond of oocytes fertilized with semen from high (52.630%) and low (58.1X27 %) fertility groups tended (p>O.O5) to be higher than those fertilized by medium fertility bulls (33ti8%). Regression analysis indicated that there was no correlation between sire fertility and in vitro embryo cleavage (R* = .1517) or development to compact morula or beyond (R* = .03). In the sperm co-culture system there were no differences in embryo cleavage rates between BOEC monolayers (5 1.2K?2%), BRLC monolayers (60.1 fiO%) and the cell free controls (59.8+17%). The BRLC monolayer treatment had a significantly higher number of embryos developing to compact morula or beyond (60.8&28%) compared to the BOEC monolayers (42.3*33%) and control wells (39.1K24). In conclusion, these studies suggest that there is not a predictive relationship between bull field fertility and in vitro embryo cleavage or development, however oocytes inseminated with sperm co-cultured on BRLC monolayers develop to the morula stage or beyond at a higher rate compared to BOEC or cell free systems.
Theriogenology EFFECTS OF BULLS WITH DIFFERENT FIELD FERTILITY ON IN VITRO EMBRYO CLEAVAGE AND DEVELOPMENT USING SPERM CO-CULTURE SYSTEMS CS Schneider JE Ellington and RW Wright Jr. Department of Animal Sciences, Washington State University Pullman WA 99 164-6332
Development of an in vitro assay system to determine bull fertility would result in tremendous economic savings compared to expensive field fertility trials. The objectives of these experiments were to compare rates of in vitro fertilization and embryo development following oocyte exposure to sperm from bulls of known field fertility. Concomitantly, the effects of sperm co-culture systems using Bovine Oviductal Epithelial Cells (BOEC), Buffalo Rat Liver Cells (BRLC) or cell free cultures (Control) were examined. Semen from nine bulls (Select Sires Inc.) was classified, by 60-90 day nonreturn rates, as having either: high (n=3) 73.2k3.0, medium (s3) 70.3f1.9 or low (n=3) 65.8ti.7 field fertility. An initial experiment was performed to determine the optimal level of heparin needed to facilitate capacitation in the different bulls. Analysis of embryo cleavage rates indicated that addition of 10 IU of heparin to the fertilization media smliciently capacitated sperm from all bulls. In experiment II, a total of 1,321 oocytes were exposed to IVMAVF yielding .737 embryos 2 2 cell which developed into 343 embryos 2 compact morula. There was no difference in embryo cleavage rates between the high (57.5*18%), medium (56.8fi3%) and low (56.9+18%) fertility groups. Development to morula or beyond of oocytes fertilized with semen from high (52.630%) and low (58.1X27 %) fertility groups tended (p>O.O5) to be higher than those fertilized by medium fertility bulls (33ti8%). Regression analysis indicated that there was no correlation between sire fertility and in vitro embryo cleavage (R* = .1517) or development to compact morula or beyond (R* = .03). In the sperm co-culture system there were no differences in embryo cleavage rates between BOEC monolayers (5 1.2K?2%), BRLC monolayers (60.1 fiO%) and the cell free controls (59.8+17%). The BRLC monolayer treatment had a significantly higher number of embryos developing to compact morula or beyond (60.8&28%) compared to the BOEC monolayers (42.3*33%) and control wells (39.1K24). In conclusion, these studies suggest that there is not a predictive relationship between bull field fertility and in vitro embryo cleavage or development, however oocytes inseminated with sperm co-cultured on BRLC monolayers develop to the morula stage or beyond at a higher rate compared to BOEC or cell free systems.