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

Abstract

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 micro M vitamin E (SFCS + E). Blastocyst yields were recorded and fatty acid composition was determined by gas chromatography. Day 7 blastocysts were incubated with [2-(14)C] 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.

Predictive value of bovine follicular components as markers of oocyte developmental potential

“…Increased concentrations of both palmitic acid and stearic acid impair meiosis, cleavage rate and blastocyst formation as well as exerting adverse effects on both bovine and human (Mu et al 2001) granulosa cell growth and function. High concentrations of fatty acids are associated with impaired embryo quality through lipid accumulation (Reis et al 2003), and developmentally competent human oocytes exhibit low levels of saturated fatty acids (Haggarty et al 2006). In the present study, the follicular fluid associated with oocytes that formed blastocysts had higher concentrations of the n-3 PUFA linolenic acid.…”

Effects of omega-3 and -6 polyunsaturated fatty acids on ovine follicular cell steroidogenesis, embryo development and molecular markers of fatty acid metabolism

“…Lipid accumulation by ovine embryos cultured in the presence of serum has been reported previously and this was also associated with markers of impaired embryo quality (Thompson et al 1995, Reis et al 2003a. Lipid peroxidation was also enhanced in Day-3 sheep embryos cultured with FAF-BSA, to which DHA (C22:6n-3) was complexed, leading to arrested development at the 8-16-cell stage (Reis et al 2003b).…”

Metabolite concentrations in follicular fluid may explain differences in fertility between heifers and lactating cows

“…This taken together with the compositional differences observed in the present study supports the hypothesis that high palmitic acid levels may have a negative impact on oocyte and embryo quality. Ultimately, the high levels of SFA in cows will lead to the accumulation of these lipids in the oocytes and embryos, and excessive lipid accumulation has been shown to impair embryo quality (Abe et al 1999, Reis et al 2003. The total PUFA fraction and the percentage contribution of PUFA to the total fatty acid pool are significantly higher in follicular fluid from cows compared with heifers.…”