143DIETARY CARBOHYDRATES AND LIPIDS AFFECT IN VITRO EMBRYO PRODUCTION FOLLOWING OPU IN HEIFERS
Adamiak SJ., Mackie K., Ewen M., Powell KA., Watt RG., Rooke JA., Webb R., Sinclair KD.
<jats:p> The superstimulation protocol of Blondin et al. (2002; Biol. Reprod. 66, 38–43) produces cumulus-oocyte complexes (COCs) of high developmental competence for IVP. Using a similar protocol we assessed the affects of alterations in oocyte donor carbohydrate and lipid metabolism during ovarian stimulation on the production and viability of blastocysts in vitro. A 2×2 factorial experiment offered two diets: Fiber (F) and Starch (S) alone (0) or with 6%w/w (6) protected lipid (calcium soaps of fatty acids). Thirty-two heifers ranked by body condition score (scale: 1=thin, 5=obese) were allocated within score to one of the 4 treatments: F0, F6, S0 and S6. COCs were collected 5 days after estrus by OPU for lipid analysis. Ovarian stimulation (4 doses of FSH (9mg NIADDK oFSH) given 12h apart) commenced 2 days later. COCs were collected 40h after the last FSH injection. GnRH (0.012mg Buserelin) was administered i.v. 6h prior to OPU. A second period of ovarian stimulation and OPU then followed. Following IVM/IVF, zygotes were cultured in SOF with 0.3%w/v fatty acid-free BSA under oil (38.8°C, 5% CO2, 5% O2, 90% N) until Day 8 of development, when blastocysts were subjected to total cell counts and TUNEL analysis. Data were analyzed by ANOVA. Neither follicles aspirated (25.9±1.87) nor oocytes recovered (12.1±0.92) differed between treatments. Total fatty acids in plasma were greater (P&lt;0.001) for the F than for the S diets and increased with the inclusion of protected lipid (0.75, 1.82, 0.50 and 1.39μgmL−1 for F0, F6, S0 and S6, respectively; SED=0.076). The dietary lipid-induced increase in plasma fatty acids was reflected in an increase (P&lt;0.05) in total fatty acids within the oocyte (70.4, 74.7, 69.9 and 78.4 ng/oocyte; SED=3.41). Retrospective analysis by body condition indicated that S diets reduced (P=0.006) blastocyst yields in thin heifers and reduced (P=0.02) cleavage rates in fat heifers (Table 1). Blastocyst yields were lower (P=0.1) for fat heifers on the F0 diet. Total cell numbers were greater for thin heifers on S0 than F0 diet. TUNEL-positive cells averaged 4.2±0.48% and did not differ between treatments. In conclusion, modification of oocyte donor carbohydrate and lipid metabolism prior to OPU can influence IVP outcome in a complex manner dependent on body composition. Supported by Defra and The Perry Foundation. Table 1 In vitro blastocyst yields and total cell numbers </jats:p>