Development of one-cell porcine embryos in two culture systems.

The effect of culture system and protein supplementation on the development of one-cell porcine embryos was investigated. One hundred and sixty-four one-cell embryos were collected at slaughter from 19 handmated gifts. Culture systems evaluated were microdrops of Whitten's medium (WM) under paraffin oil (M) or tubes with 4.0 ml of WM (T). Also tested was T with a 2.0 ml paraffin oil overlay (O). Media evaluated were WM with: no bovine serum albumin (-BSA), 15 mg/ml BSA (+BSA) or 10% (v/v) heat-treated porcine serum (+HTPS). Twenty-nine, 29, 28, 29, 28 and 21 one-cell embryos were assigned to treatments T + BSA + O, T - BSA, M + BSA, M - BSA and M + HTPS, respectively. All cultures were conducted at 37 C in a humidified atmosphere of 5% CO2 in air. At the cessation of division, embryos were fixed and stained, and each was assigned a cleavage index bases on the number of divisions completely in culture. The mean cleavate indexes for embryos cultured in T + BSA + O (2.07) and T + BSA (1.97) were not significantly different, but both were greater (P less than .05) than the indexes for T - BSA (1.09), M + BSA (1.12), M - BSA (.82) and M + HTPS (.86). Mean cleavage indexes for embryos cultured in T - BSA, M + BSA, M - BSA and M + HTPS were not significantly different. More (P less than .05) embryos developed to the blastocyst stage in T + BSA + O (6/29) than in either T - BSa (0.28) or M BSA (0.28). Fragmentation was greater (P less than .05) in embryos cultured in M - BSA than in embryos cultured in tubes. These results suggest that culture tubes of WM with 1.5% BSA are superior to microdrops and WM with 10% HTPS in supporting the in vitro development of one-cell porcine embryos.