Theriogenology. 2016 Jan 30. pii: S0093-691X(16)00032-7. doi: 10.1016/j.theriogenology.2016.01.019. [Epub ahead of print]
- 1INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR 7247 Physiologie de la Reproduction et des Comportements, Nouzilly, France; Université François Rabelais de Tours, UMR Physiologie de la Reproduction et des Comportements, Nouzilly, France; IFCE, UMR Physiologie de la Reproduction et des Comportements, Nouzilly, France.
- 2INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR 7247 Physiologie de la Reproduction et des Comportements, Nouzilly, France; Université François Rabelais de Tours, UMR Physiologie de la Reproduction et des Comportements, Nouzilly, France; IFCE, UMR Physiologie de la Reproduction et des Comportements, Nouzilly, France. Electronic address: Sebastien.Elis@tours.inra.fr.
Abstract
The
positive effect of n-3 polyunsaturated fatty acids (FAs) on fertility
in ruminants seems to be partly mediated through direct effects on the
oocyte developmental potential. We aimed to investigate whether
supplementation with physiological levels of docosahexaenoic acid (DHA,
C22:6 n-3 polyunsaturated fatty acids) during IVM has an effect on
oocyte maturation and in vitro embryo development in cattle.
We reported that DHA (0, 1, 10, or 100 μM) had no effect on oocyte
viability or maturation rate after 22-hour IVM. Incubation of
oocyte-cumulus complexes with 1-μM DHA during IVM significantly
increased (P < 0.05) oocyte cleavage rate as compared with control
(86.1% vs. 78.8%, respectively) and the greater than 4-cell embryo rate
at Day 2 after parthenogenetic activation (39.1% vs. 29.7%,
respectively). Supplementation with 1 μM DHA during IVM also induced a
significant increase in the blastocyst rate at Day 7 after IVF as
compared with control (30.6% vs. 17.6%, respectively) and tended to
increase the number of cells in the blastocysts (97.1 ± 4.9 vs.
81.2 ± 5.3, respectively; P = 0.08). On the contrary, 10-μM DHA had no
effects, whereas 100-μM DHA significantly decreased the cleavage rate
compared with control (69.5% vs.78.8%, respectively) and the greater
than 4-cell embryo rate at Day 2 after parthenogenetic activation (19.5%
vs. 29.7%). As was shown by real-time polymerase chain reaction,
negative effects of 100-μM DHA were associated with significant increase
of progesterone synthesis by oocyte-cumulus complexes, a three-fold
increase in expression level of FA transporter CD36 and a two-fold
decrease of FA synthase FASN genes in cumulus cells (CCs) of
corresponding oocytes. Docosahexaenoic acid at 1 and 10 μM had no effect
on expression of those and other key lipid metabolism-related genes in
CC. In conclusion, administration of a low physiological dose of DHA
(1 μM) during IVM may have beneficial effects on oocyte developmental
competence in vitro without affecting lipid metabolism gene expression
in surrounding CCs, contrarily to 100 μM DHA which diminished oocyte
quality associated with perturbation of lipid and steroid metabolism in
CC.
Copyright © 2016 Elsevier Inc. All rights reserved.
KEYWORDS:
Cumulus; Gene expression; IVM; Oocyte competence; n-3 PUFA
