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) (c9,t11 CLA and t10,c12 CLA) or stearic acid 18:0 (SA) on top of an isocaloric grass silage diet. Two supplementation doses were used (100 g/d and 200 g/d). Blood and follicular fluid were collected at the start and end of the supplementation period for analysis of cholesterol, IGF, NEFA and for fatty acid profiling. While 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. The relative abundance of target genes (IGF1r, GJA1, FASN, SREBP1 and SCAP) was analyzed in single in vitro (24h IVM) and in vivo matured (collected by OPU 20h after GnRH injection) oocytes and in vitro produced blastocysts (d8) by qPCR (n=6/group). Lipid profiling of individual oocytes (n=82) was performed by desorption electrospray ionization mass spectrometry (DESI-MS). In vitro maturation (n=541) and blastocysts (n=222) rates were assessed. 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 in comparison to their in vivo matured counterparts. Maturation (CLA=74% vs. SA=67%) and blastocyst rates (CLA=22.4% vs. 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.
Specific Fatty Acid Follow-Up Reveals Rumen-Protected Fat Supplementation Effects on Bovine Oocyte Quality and Embryo Development
PIRRO, VALENTINA;
2014-01-01
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) (c9,t11 CLA and t10,c12 CLA) or stearic acid 18:0 (SA) on top of an isocaloric grass silage diet. Two supplementation doses were used (100 g/d and 200 g/d). Blood and follicular fluid were collected at the start and end of the supplementation period for analysis of cholesterol, IGF, NEFA and for fatty acid profiling. While 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. The relative abundance of target genes (IGF1r, GJA1, FASN, SREBP1 and SCAP) was analyzed in single in vitro (24h IVM) and in vivo matured (collected by OPU 20h after GnRH injection) oocytes and in vitro produced blastocysts (d8) by qPCR (n=6/group). Lipid profiling of individual oocytes (n=82) was performed by desorption electrospray ionization mass spectrometry (DESI-MS). In vitro maturation (n=541) and blastocysts (n=222) rates were assessed. 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 in comparison to their in vivo matured counterparts. Maturation (CLA=74% vs. SA=67%) and blastocyst rates (CLA=22.4% vs. 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.
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