2 Specific Fatty Acid Follow-Up Reveals Rumen-Protected Fat Supplementation Effects on Bovine Oocyte Quality and Embryo Development

Abstract

Information on how supplementation of high-yield dairy cows with rumen-protected fat affects fertility in cattle herds is scarce. Here, Holstein-Friesian heifers (n = 84) received a supplement consisting of either rumen-protected conjugated linoleic acid (CLA; cis-9,trans-11-CLA and trans-10,cis-12-CLA) or stearic acid 18 : 0 (SA) on top of an isocaloric grass silage diet. Two supplementation doses were used (100 and 200 g d–1). Blood and follicular fluid were collected at the start and end of the supplementation period for analysis of cholesterol, insulin-like growth factor (IGF), and nonesterified fatty acids (NEFA), and for fatty acid profiling. Although cholesterol, IGF, and NEFA levels did not differ among experimental groups, lipid profiles in blood and follicular fluid were affected in a dose-dependent manner by both supplements. After 45 days of supplementation, oocytes were collected by ovum pick-up (OPU). The mRNA relative abundance of target genes (IGF1r, GJA1, FASN, SREBP1, and SCAP) was analysed in single in vitro- (24 h IVM) and in vivo-matured (collected by OPU 20 h after GnRH injection) oocytes and in vitro-produced blastocysts (Day 8) by qPCR (n = 6/group). Lipid profiling of individual oocytes from the CLA-supplemented (n = 37) and the SA-supplemented (n = 50) was performed by desorption electrospray ionization mass spectrometry (DESI-MS). Oocytes from the CLA-supplemented (n = 413) and the SA-supplemented (n = 350) groups were used for assessing maturation and blastocysts development rates. In immature oocytes, CLA supplementation led to an increase of triacylglycerol 52 : 3 [TAG (52 : 3)] and TAG (52 : 2), squalene, palmitic acid 16 : 0, and oleic acid 18 : 1, and decreased abundance of TAG (56 : 3), TAG (50 : 2) and TAG (48 : 1). In vitro-matured oocytes showed different lipid profiles, with increased abundances of TAG (52 : 3), and TAG (52 : 2) as well as phosphatidylinositol 34 : 1 [Plo (34 : 1)], whereas phosphatidylglycerol (34 : 1) [PG (34 : 1)] and palmitic acid 16 : 0 were less abundant in in vitro-matured oocytes. SCAP was significantly down-regulated in in vitro-matured oocytes from supplemented heifers compared with their in vivo-matured counterparts. Maturation (CLA = 74% v. SA = 67%) and blastocyst rates (CLA = 22.4% v. SA = 12.7%) were different among experimental groups. One-way ANOVA and the Tukey-Kramer test were applied for a multiple comparison of means (P-value ≤ 0.05 was considered as statistically significant). In conclusion, we demonstrate here that fatty acid monitoring along different compartments (i.e. blood system, follicular fluid, and intra-oocyte) after rumen-protected fat supplementation of dairy heifer diet reveals nutritional footprints on oocyte quality and embryo development. These results demonstrate the close relationship between nutrition and cattle herd's fertility and, at the same time, support the role of the bovine model for understanding nutritional-dependent fertility impairments.

Cell Signalling During Blastocyst Morphogenesis

“…Dietary supplementation of rumen-protected conjugated linoleic acid (CLA) has been shown to help overcome fertility problems by increasing oocyte maturation and blastocyst development. This beneficial effect is linked to altered fatty acid composition and gene expression patterns of oocytes and embryos (Gonzalez-Serrano et al 2013a). The development of techniques sufficiently sensitive to determine the fatty acid profile of individual oocytes and preimplantation embryos may help to elucidate signalling events involving fatty acids, their transporters and downstream metabolic pathways further after maternal dietary challenge (Gonzalez-Serrano et al 2013b).…”

49 Effects of Dietary Conjugated Linoleic Acid Supplementation on Bovine Oocyte Lipid Metabolism, Lipid Composition, and Embryo Cryotolerance

“…A slightly different mass spectrometry technique known as desorption electrospray ionization (DESI-MS) has been used to evaluate embryo lipids in oocytes and embryos from cows (Ferreira et al, 2011(Ferreira et al, , 2012bGonzález-Serrano et al, 2013a;González-Serrano et al, 2013b) and mice (Ferreira et al, 2012a). This is an ambient ionization used for MS analysis of lipids directly from biological samples with no sample preparation.…”