Consequences of exposure to serum, with or without vitamin E supplementation, in terms of the fatty acid content and viability of bovine blastocysts produced in vitro

To determine whether serum supplementation influenced fatty acid content of bovine blastocysts and whether vitamin E addition to culture medium containing serum could improve development in vitro, cleaved eggs were cultured in synthetic oviduct fluid supplemented with bovine serum albumin (BSA, 0.4% w/v, fraction V) (SVBSA), fetal calf serum (FCS, 10% v/v) (SFCS) or FCS ( 10% v/v) plus 100 mum vitamin E (SFCS+ E). Blastocyst yields were recorded and fatty acid composition was determined by gas chromatography. Day 7 blastocysts were incubated with [2-C-14] pyruvate for 3 h and then fixed for cell counts. Yields of good quality blastocysts were greatest from cleaved eggs cultured in serum-free conditions ( P < 0.01). In the presence of serum, supplementation with vitamin E increased both total and good quality blastocyst yields ( P < 0.01). Presence of serum increased fatty acid content ( mean +/- SEM) of blastocysts ( SVBSA v. SFCS= 57 +/- 2 v. 74 +/- 2 ng embryo(-1); P < 0.001). In contrast, pyruvate metabolism was greater in blastocysts produced without serum ( 27 +/- 3 v. 21 +/- 3 picomoles embryo(-1) 3h(-1); P < 0.01) but, on a per cell basis, no differences were detected. Addition of vitamin E to the serum-supplemented formulation did not alter either the fatty acid content ( 73 +/- 2 ng embryo(-1)) or pyruvate metabolism index ( 19 +/- 1 pmol embryo(-1) 3h(-1)) of SFCS+ E blastocysts. Thus, despite lipid accumulation, supplementary vitamin E improved blastocyst yields in embryos exposed to serum.