| This thesis studied issues related to sex control in mammals, and it is arranged in two parts: part I includes chaper I and chaper II, which is a review of literatures; part II includes chaper III-VI, which deals with the experimental work.The objectives of these studies in chaper III and chaper IV were to determine the effect of flow cytometrically-sorted, stained and unsorted sperm on in vitro fertilization and blastocyst development of bovine oocytes and determine if the sorting procedure and staining cause chromosomal abnormalities. A total of 4273 oocytes aspirated from slaughterhouse ovaries and three types of frozen sperm (sorted, stained and unsorted sorted, stained and unsorted) from 3 bulls (3 to 5 replicates of each bull) were used for IVF. In addition, a total of 351 IVF biastocysts (6 d-8 d) were subjected to cytogenetic analysis. Data were analyzed by ANOVA procedures or Chisquare. The results reveal that: 1) there was no significant difference in blastocyst rate among the three types of sperm (20.4%, 22.6% and 22.1% for sorted, stained and unsorted sperm, respectively); however, the cleavage rate with sorted sperm (53.1%) was lower (p<0.05) than that with unsorted sperm (69.7%); 2) there were significant differences in cleavage and blastocyst rates among bulls tested, i.e. there was significant reduction in cleavage (40.6% vs 74.4% and 69.8%; p<0.05) when using sperm from bull H008 compared to bull H010 and HO16; and there was also significant reduction in biastocysts (17.4% vs 25.1% ; p<0.05) when using spermfrom bull H008 compared to bull H010. 3) there were no significant differences in chromosomal abnormaiity(mosaic) rate of blastocysts derived from sorted, stained unsorted and unsorted sperm (57%, 82/145; 59%, 59/106 and 65.0%, 65/100, respectively); 4) Chromosomal abnormality rates were variant among three bulls, i.e. there was a significant difference in chromosomal abnormalities rate between buil H016 and H008 (30% vs 45%; p<0.05); 5) there was no significant difference in chromosomal abnormality rate of blastocysts in D6, D7, and D8. These results indicated that: 1) neither sorting procedure nor staining affec embryo development to blastocysts stage and the chromosomal composition of embryos, which demonstrates that flow cytometrically-sorted sperm can be effectively used for in vitro production of bovine embryos; 2) chromosomal composition of embryos is not affected by development stage of embryos.This study in chaper V was to compare the development and chromosomal composition status of bovine embryos produced by iC SI and IVF with flow cytometrically-sorted X and Y-chromosome-bearing sperm, as well as unsorted sperm from one bull (H010) in order to determinate if sorted sperm have an influence on the results of ICSI. Analysis revealed that l)there was no significant difference either in cleavage or blastocyst development rates between ICSI and IVF with three types of sperm (the cleavage rate with sorted sperm in IVF was lower than that with unsorted sperm, p<0.05) ; 2) there was also no significant difference either in cleavage or blastocyst development rates with the same type of sperm for IVF and ICSI, and the rates of cleavage and blastocyst with sorted sperm for ICSI were similar to that for IVF (71.75% vs 65%, 22.1% vs 25.6%). Blastocysts on day 7 and day 8 were treated with hypotonic solution and fixed on slide and stained for cell count and analysis of chromosomes. The results indicate that there were no significant difference in cell numbers of embryos from ICSI and1VF with three types of sperm (X, Y, and unsorted sperm (p>0.1), but cell numbers of ICSI embryos were lower than that of IVF embryos (p<0.005); There were no significant difference in the rates of chromosomal abnormalities with X, Y, and unsorted sperm in ICSI or IVF embryos produced, and there were also no significant difference in the rates of chromosomal abnormalities between ICSI (30.9%) and IVF (33.6%). In conclusion, sorted sperm has no influence on the development of embryos from ICSI. Neith...
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