Data Analysis Data were analyzed as an incomplete block design, or a randomized block design, blocked on plate using mi ed model procedures of SAS. At least si replicates were completed for selleck compound each e periment. Fishers protected least significant differences were used for separating least square differences for e per iments 1, 2, 3, and a two tailed Students T test was per formed on data from e periment 4. Least square means S. E. M. are e pressed as the proportion of putative zygotes. All data were subjected to a normality test and were found to be normally distributed. Results In the first e periment addition of 5 M retinol during IVM tended to improve embryonic develop ment to the blastocyst stage, compared to controls. The control blastocyst rate was 21. 9% compared to 26. 1% in 5 M retinol.
Addition of 1 M retinol to the mat uration medium did not appear to affect embryonic devel opment compared to controls. Retinol increased blastocyst development, although not significantly. Cleavage rates did not differ among the four maturation treatments. Further analysis of the maturation data revealed that when development to the blastocyst stage of controls was below 20%, 5 M retinol dramatically improved embryo development. When e pressed as blastocyst cleaved the 5 M retinol treatment also showed a significant improvement in blastocyst development. Neither 1 M nor 10 M retinol treatment improved embryonic development when com pared to those controls that did not achieve a 20% blasto cyst rate. Further e periments were conducted during IVC under both low and atmospheric o ygen tensions.
Under low o ygen conditions concentrations of 1, 2, and 5 M retinol were not statistically different from controls, and 10 M was deleterious. Preliminary dose response studies were performed under atmospheric conditions, and additional e periments were con tinued with the 5 M retinol treatment. Under atmos pheric o ygen conditions the 5 M concentration significantly improved blastocyst development compared to controls. Cleavage rates did not differ significantly among embryos treated with and with out retinol during culture under low or high o ygen. Fertilization rates did not differ signifi cantly among all e periments. Discussion In the present study, over 3000 bovine oocytes were used to evaluate effects of retinol supplementation during IVM and IVC on embryonic development to the blastocyst stage.
Retinol administration during the maturation period alone resulted in concentration dependent effects. Whereas the presence of 1 M retinol had no effect on development, 5 M retinol tended to improve blastocyst rate of development, at the p 0. 07 level, compared to controls. At a concentration of 10 M, Entinostat retinol did not sig nificantly improve embryo development compared to controls. In preliminary studies, higher concentrations were observed to be cytoto ic.