scholarly journals Non-esterified fatty acids in follicular fluid of dairy cows and their effect on developmental capacity of bovine oocytes in vitro

Reproduction ◽  
2005 ◽  
Vol 130 (4) ◽  
pp. 485-495 ◽  
Author(s):  
J L M R Leroy ◽  
T Vanholder ◽  
B Mateusen ◽  
A Christophe ◽  
G Opsomer ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Dairy Cows ◽  
Follicular Fluid ◽  
Post Partum ◽  
Cumulus Cells ◽  
Negative Control ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Esterified Fatty Acids

In this study concentration and composition of non-esterified fatty acids (NEFA) in follicular fluid (FF) of high-yielding dairy cows were determined during the period of negative energy balance (NEB) early post partum. NEFA were then added during in vitro maturation at concentrations measured previously in FF to evaluate their effect on the oocyte’s developmental competence. At 16 and 44 days post partum, FF of the dominant follicle and blood were collected from nine high-yielding dairy cows. Samples were analysed for NEFA concentration and composition. NEFA concentrations in FF (0.2–0.6 mmol/l) during NEB remained ± 40% lower compared with serum (0.4–1.2 mmol/l). The NEFA composition differed significantly between serum and FF with oleic acid (OA), palmitic acid (PA) and stearic acid (SA) being the predominant fatty acids in FF. Based on these results, 5115 oocytes were matured for 24 h in serum-free media with or without (negative control) the addition of 0.200 mmol/l OA, 0.133 mmol/l PA or 0.067 mmol/l SA dissolved in ethanol or ethanol alone (positive control). Matured oocytes were fertilized and cultured for 7 days in SOF medium. Addition of PA or SA during oocyte maturation had negative effects on maturation, fertilization and cleavage rate and blastocyst yield. More (late) apoptotic cumulus cells were observed in cumulus–oocyte complexes matured in the presence of SA or PA. Ethanol or OA had no effect. These in vitro results suggest that NEB may hamper fertility of high-yielding dairy cows through increased NEFA concentrations in FF affecting oocyte quality.

327 UNSATURATED AND SATURATED NON-ESTERIFIED FATTY ACIDS DIFFERENTLY AFFECT LIPID STORAGE AND DEVELOPMENTAL COMPETENCE OF BOVINE OOCYTES

2010 ◽  
Vol 22 (1) ◽  
pp. 319
Author(s):  
H. Aardema ◽  
P. Vos ◽  
H. Knijn ◽  
B. Roelen ◽  
B. Gadella
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Palmitic Acid ◽  
Lipid Droplet ◽  
Lipid Droplets ◽  
Post Partum ◽  
Developmental Competence ◽  
Negative Effects ◽  
Esterified Fatty Acids

Fertility in high-producing dairy cows has declined over the last decades. An increased serum and follicular fluid concentration of non-esterified fatty acids (NEFAs), due to body fat mobilization in the early post partum period, has been postulated as a cause for this fertility decline. NEFA concentrations and composition may change in the environment of the oocyte and thus might affect the storage depots of esterified NEFAs in the oocyte. We exposed COCs to unsaturated (oleic acid) or saturated (palmitic acid) NEFAs during maturation and subsequently examined lipid droplets and developmental competence of the oocytes. COCs from 3-8 mm follicles of slaughterhouse ovaries were cultured in control maturation medium (TCM-199) and medium containing 100, 250, or 500 μM oleic and/or palmitic acid (10 mM fatty acid was bound to 10% BSA fatty acid free). These concentrations were based on in vivo measured NEFA concentrations in follicular fluid in the early post partum period (Leroy et al. 2005 Reproduction 130, 485-495). After 23 h of maturation, COCs were fertilized (450 per group) and cultured till the blastocyst stage, or fixed (80 per group) for lipid droplet staining with C1-BODIPY® 500/510 C12. Confocal microscopy was performed to determine lipid droplet size in (im(mean) and the number of lipid droplets per oocyte. Lipid droplet number and the log of size were analyzed using analysis of variances with condition as fixed factor. Variation was described as the standard error of the mean. Similar concentrations of palmitic or oleic acid had an opposite effect on the size of lipid droplets in oocytes. The number of lipid droplets dramatically decreased in oocytes exposed to 500 μM palmitic acid (178 ± 20), whereas the number increased after exposure to 500 μM oleic acid (554 ± 15). The number of lipid droplets of oocytes exposed to a combination of 250 μM palmitic acid and 250 μM oleic acid (421 ± 23) was comparable with the control and lower oleic and palmitic acid concentrations. Exposure of COCs to palmitic acid during maturation resulted in reduced blastocyst development in a dose-dependent manner (from 18 ± 1.4%, 13 ± 2.4% to 2.8 ± 1.3% after exposure to 500 μM) when compared to control (20 ± 2.2%) or oocytes exposed to oleic acid (from 23 ± 1.6%, 23 ± 3.3% till 28 ± 3.3%). Negative effects of palmitic acid were counteracted by simultaneous exposure to oleic acid during in vitro oocyte maturation (26 ± 5.5%). We conclude that palmitic acid elicited negative effects on early embryonic development, possibly because it induces a reduction in the number of lipid droplets. These adverse effects can be offset by oleic acid during maturation. Moreover a high oleic acid concentration increased the number and size of lipid droplets of oocytes. The regulatory pathways involved in the noted differences in lipid storage features of in vitro-matured oocytes as well as the adverse effects of palmitic acid on early embryonic development are currently under research.

206 EFFECT OF ADDITION OF FOLLICULAR FLUID OR GROWTH DIFFERENTIATION FACTOR-9 ON IN VITRO MATURATION OF PORCINE OOCYTES DENUDED 20h AFTER THE START OF IN VITRO MATURATION

2016 ◽  
Vol 28 (2) ◽  
pp. 234
Author(s):  
P. Ferré ◽  
T. T. M. Bui ◽  
M. T. Tran ◽  
T. Wakai ◽  
H. Funahashi
Keyword(s):  
Follicular Fluid ◽  
In Vitro Maturation ◽  
Cumulus Cells ◽  
Developmental Competence ◽  
Dapi Staining ◽  
Experimental Conditions ◽  
Nuclear Maturation ◽  
Differentiation Factor ◽  
Growth Differentiation Factor 9

The interruption of communication between oocyte and cumulus cells (CC) can trigger meiotic resumption and exogenous additives, such as follicular fluid (FF) and growth differentiation factor-9 (GDF9), can improve oocyte quality and the developmental competence. This study was undertaken to examine if the absence and presence of FF from medium follicles (MF; 3–6 mm in diameter) or recombinant human GDF9 (Biovision, Milpitas, CA, USA) during the first or/and second half of in vitro maturation (IVM) had any effects on IVM of oocytes from small follicles (SF; 0.5–2 mm in diameter) or MF when the oocytes were denuded at 20 h after the start of IVM. Cumulus-oocyte complexes (COC) were aspirated from SF or MF of slaughtered prepubertal gilt ovaries. Groups of ~30 COC were cultured in a 300-μL drop of porcine oocyte medium containing 50 µM β-mercaptoethanol (mPOM) with or without 10% (v/v) FF and/or 100 ng mL–1 GDF9 at 39°C and 5% CO2 in air. During the first 20 h after the start of IVM, the medium was supplemented with 1 mM dibutyryl c-AMP, 10 IU mL–1 eCG and 10 IU mL–1 hCG. After the first period of IVM, the CC surrounding the oocytes were removed and the denuded oocytes continued culture for IVM with or without FF or/and GDF9 in the absence of dibutyryl c-AMP and gonadotropins in the same medium for another 24 h. At the end of IVM, meiotic progression of the oocytes was examined by DAPI staining. Statistical analyses from at least 4 replicates data were performed by a 2-way ANOVA and a Tukey’s multiple comparisons test. Removal of CC 20 h after the start of IVM significantly improved the incidence of mature oocytes derived from SF (59.2–64.1% v. 41.6–43.1% in controls, P < 0.05) but not from MF (73.1–78.5% v. 70.6–71.8% in controls), whereas regardless of supplementation with FF or GDF9, the maturation rates were always significantly higher in the denuded oocytes from MF (72.4–83.6%) than SF (57.8–66.2%; P < 0.05). Despite of the origin of COC (SF or MF), maturation rates of oocytes denuded 20 h after the start of IVM were not affected by supplementation with FF or GDF9 during the first and/or second half of IVM (P > 0.05). In summary, CC removal from COC 20 h after the start of IVM promotes nuclear maturation of oocytes from SF. Exogenous additives such as GDF9 and follicular fluid from MF do not seem to affect the promotion of nuclear maturation in our experimental conditions.

scholarly journals Dietary α-linolenic acid from flaxseed oil improved folliculogenesis and IVF performance in dairy cows, similar to eicosapentaenoic and docosahexaenoic acids from fish oil

Reproduction ◽  
2013 ◽  
Vol 146 (6) ◽  
pp. 603-614 ◽  
Author(s):  
U Moallem ◽  
A Shafran ◽  
M Zachut ◽  
I Dekel ◽  
Y Portnick ◽  
...  
Keyword(s):  
Fish Oil ◽  
Dairy Cows ◽  
Linolenic Acid ◽  
Post Partum ◽  
Saturated Fat ◽  
Docosapentaenoic Acid ◽  
Flaxseed Oil ◽  
Omega 3 ◽  
Cleavage Rate

The objectives of this study were to determine the differential incorporation of various omega-3 (n-3) fatty acids (FAs) supplemented to dairy cows into ovarian compartments and assess the effects on IVF. Forty-two 256-day pregnant cows were supplemented with encapsulated fats, in treatments designated as i) SFA – saturated fat at 240 and 560 g/day per cow, prepartum and post partum (PP) respectively; ii) FLX – flaxseed oil at 300 and 700 g/day per cow prepartum and PP respectively; and iii) FO – fish oil at 300 and 700 g/day per cow prepartum and PP respectively. Commencing at 60 days in lactation, ovum pickup (OPU) was performed twice weekly (20 sessions; five cows per group) and in vitro maturation and IVF were conducted. The proportion of α-linolenic acid (ALA) was greater in follicular fluid (FF), granulosa cells, and cumulus–oocyte complexes (COCs) of FLX cows than in other groups (P<0.001). The proportion of docosahexaenoic acid (DHA) was 6.7 times as great in FF of FO as in other groups (P<0.001); docosapentaenoic acid n-3 and DHA were detected in COCs of FO but not in others. The follicle number during OPU was higher in FLX and FO than in SFA (P<0.05), and the oocyte cleavage rate was higher in FLX and FO than in SFA (P<0.01). Also, the percentage of oocytes that developed to blastocysts tended to be higher in both n-3 groups than in SFA (P<0.1). In conclusion, both dietary n-3 FAs similarly improved folliculogenesis and IVF performance; therefore, ALA-rich botanical n-3 seems to be a satisfactory approach to improve oocyte quality.

scholarly journals Developmental competence in vivo and in vitro of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection with fresh or frozen-thawed spermatozoa

Reproduction ◽  
2002 ◽  
pp. 455-465 ◽  
Author(s):  
YH Choi ◽  
CC Love ◽  
LB Love ◽  
DD Varner ◽  
S Brinsko ◽  
...  
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Polar Body ◽  
Cumulus Cells ◽  
Fertilization Rate ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
First Polar Body ◽  
Bovine Oocytes

This study was undertaken to evaluate the development of equine oocytes in vitro and in vivo after intracytoplasmic sperm injection (ICSI) with either fresh or frozen-thawed spermatozoa, without the use of additional activation treatments. Oocytes were collected from ovaries obtained from an abattoir and oocytes classified as having expanded cumulus cells were matured in M199 with 10% fetal bovine serum and 5 microU FSH ml(-1). After 24-26 h of in vitro maturation, oocytes with a first polar body were selected for manipulation. Fresh ejaculated stallion spermatozoa were used for the experiment after swim-up for 20 min in sperm-Tyrode's albumen lactate pyruvate. Frozen-thawed spermatozoa from the same stallion were treated in a similar way. Spermatozoa were immobilized and injected into the oocytes using a Piezo drill. Presumptive zygotes were cultured in G1.2 medium for 20 or 96 h after the injection was administered, or were transferred to the oviducts of recipient mares and recovered 96 h later. In addition, bovine oocytes with first polar bodies were injected with the two types of stallion spermatozoa and fixed 20 h after injection to examine pronuclear formation. Fertilization rate (pronucleus formation and cleavage) at 20 h after injection of spermatozoa was not significantly different between fresh and frozen-thawed sperm groups in either equine or bovine oocytes. Pronucleus formation after injection of spermatozoa into bovine oocytes was significantly higher than that for equine oocytes (P < 0.05). There were no significant differences in cleavage rate or average number of nuclei at 96 h between equine oocytes injected with fresh or frozen-thawed spermatozoa. However, embryos developed in vivo for 96 h had a significantly higher number of nuclei in both sperm treatments compared with those cultured in vitro. These results indicate that good activation rates may be obtained after injection of either fresh or frozen-thawed equine spermatozoa without additional activation treatment. Injection of frozen-thawed equine spermatozoa results in similar embryo development to that obtained with fresh equine spermatozoa. In vitro culture of equine zygotes in G1.2 medium results in a similar cleavage rate but reduced number of cells compared with in vivo culture within the oviduct. Bovine oocytes may be useful as models for assessing sperm function in horses.

The effects of non-esterified fatty acids and β-hydroxybutyrate on the hepatic CYP2E1 in cows with clinical ketosis

2019 ◽  
Vol 86 (1) ◽  
pp. 68-72
Author(s):  
Zhicheng Peng ◽  
Xiaobing Li ◽  
Zhe Wang ◽  
Guowen Liu ◽  
Xinwei Li
Keyword(s):  
Oxidative Stress ◽  
Fatty Acids ◽  
Dairy Cows ◽  
Blood Concentrations ◽  
Cytochrome P4502e1 ◽  
Esterified Fatty Acids ◽  
Cyp2e1 Expression ◽  
Expression And Activity

AbstractDairy cows with ketosis display severe oxidative stress as well as high blood concentrations of non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB). Cytochrome P4502E1 (CYP2E1) plays an important role in the induction of oxidative stress. The aim of this study was to investigate CYP2E1 expression and activity in the liver of clinically ketotic cows (in vivo) and the effects of NEFA and BHB on CYP2E1 expression and activity in hepatocytes (in vitro). Dairy cows with clinical ketosis exhibited a low blood concentration of glucose but high concentrations of NEFA and BHB. Hepatic mRNA, protein expression, and activity of CYP2E1 were significantly higher in cows with clinical ketosis than in control cows. In vitro, both NEFA and BHB treatment markedly up-regulated the mRNA and protein expressions as well as activity of CYP2E1 in cow hepatocytes. Taken together, these results indicate that high levels of NEFA and BHB significantly up-regulate the expression and activity of hepatic CYP2E1, and may be influential in the induction of oxidative stress in cows with clinical ketosis.

scholarly journals Antioxidant Nobiletin Enhances Oocyte Maturation and Subsequent Embryo Development and Quality

2020 ◽  
Vol 21 (15) ◽  
pp. 5340
Author(s):  
Yulia N. Cajas ◽  
Karina Cañón-Beltrán ◽  
Magdalena Ladrón de Guevara ◽  
María G. Millán de la Blanca ◽  
Priscila Ramos-Ibeas ◽  
...  
Keyword(s):  
Embryo Development ◽  
Biological Effects ◽  
Calf Serum ◽  
Cumulus Cells ◽  
Developmental Competence ◽  
Mitochondrial Activity ◽  
Cortical Granules ◽  
Cleavage Rate ◽  
Cytoplasmic Maturation

Nobiletin is a polymethoxylated flavonoid isolated from citrus fruits with wide biological effects, including inhibition of reactive oxygen species (ROS) production and cell cycle regulation, important factors for oocyte in vitro maturation (IVM). Therefore, the objective of the present study was to evaluate the antioxidant activity of nobiletin during IVM on matured bovine oocyte quality (nuclear and cytoplasmic maturation; oocyte mitochondrial activity; intracellular ROS and glutathione (GSH) levels) and their developmental competence, steroidogenesis of granulosa cells after maturation, as well as quantitative changes of gene expression in matured oocytes, their cumulus cells, and resulting blastocysts. Bovine cumulus-oocyte complexes were in vitro matured in TCM-199 +10% fetal calf serum (FCS) and 10 ng/mL epidermal growth factor (EGF) (Control) supplemented with 10, 25, 50, or 100 μM of nobiletin (Nob10, Nob25, Nob50, and Nob100, respectively) or 0.1% dimethyl sulfoxide (CDMSO: vehicle for nobiletin dilution). A significantly higher percentage of matured oocytes in metaphase II was observed in Nob25 and Nob50 compared to other groups. Similarly, cleavage rate and cumulative blastocyst yield on Days 7 and 8 were significantly higher for Nob25 and Nob50 groups. Oocytes matured with 25 and 50 μM nobiletin showed a higher rate of migration of cortical granules and mitochondrial activity and a reduction in the ROS and GSH content in comparison with all other groups. This was linked to a modulation in the expression of genes related to metabolism (CYP51A1), communication (GJA1), apoptosis (BCL2), maturation (BMP15 and MAPK1), and oxidative stress (SOD2 and CLIC1). In conclusion, nobiletin offers a novel alternative for counteracting the effects of the increase in the production of ROS during IVM, improves oocyte nuclear and cytoplasmic maturation, and subsequent embryo development and quality in cattle.

scholarly journals Lipids and oocyte developmental competence: the role of fatty acids and β-oxidation

Reproduction ◽  
2014 ◽  
Vol 148 (1) ◽  
pp. R15-R27 ◽  
Author(s):  
Kylie R Dunning ◽  
Darryl L Russell ◽  
Rebecca L Robker
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Embryo Development ◽  
Oocyte Maturation ◽  
Unsaturated Fatty Acids ◽  
Cumulus Cells ◽  
Developmental Competence ◽  
Oocyte Developmental Competence

Metabolism and ATP levels within the oocyte and adjacent cumulus cells are associated with quality of oocyte and optimal development of a healthy embryo. Lipid metabolism provides a potent source of energy and its importance during oocyte maturation is being increasingly recognised. The triglyceride and fatty acid composition of ovarian follicular fluid has been characterised for many species and is influenced by nutritional status (i.e. dietary fat, fasting, obesity and season) as well as lactation in cows. Lipid in oocytes is a primarily triglyceride of specific fatty acids which differ by species, stored in distinct droplet organelles that re-localise during oocyte maturation. The presence of lipids, particularly saturated vs unsaturated fatty acids, in in vitro maturation systems affects oocyte lipid content as well as developmental competence. Triglycerides are metabolised by lipases that have been localised to cumulus cells as well as oocytes. Fatty acids generated by lipolysis are further metabolised by β-oxidation in mitochondria for the production of ATP. β-oxidation is induced in cumulus–oocyte complexes (COCs) by the LH surge, and pharmacological inhibition of β-oxidation impairs oocyte maturation and embryo development. Promoting β-oxidation with l-carnitine improves embryo development in many species. Thus, fatty acid metabolism in the mammalian COC is regulated by maternal physiological and in vitro environmental conditions; and is important for oocyte developmental competence.

Comparison between two preventive treatments for hyperketonaemia carried out pre-partum: effects on non-esterified fatty acids, β-hydroxybutyrate and some biochemical parameters during peripartum and early lactation

2021 ◽  
Vol 88 (1) ◽  
pp. 38-44
Author(s):  
Enrico Fiore ◽  
Laura Perillo ◽  
Matteo Gianesella ◽  
Claudia Giannetto ◽  
Elisabetta Giudice ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Liver Function ◽  
Dairy Cows ◽  
Repeated Measures ◽  
Post Partum ◽  
Preventive Treatment ◽  
Control Group ◽  
Early Lactation ◽  
Esterified Fatty Acids ◽  
Holstein Dairy Cows

AbstractThe objective of this study was to compare the effect of two different preventive protocols, on serum β-hydroxybutyrate (BHB) concentration and liver health indices pre-partum and during early-lactation in high-yielding Holstein dairy cows. One hundred cows were randomly divided into three groups: control group (CTRL, n = 20, without preventive treatment), second group (SUPP, n = 40 animals treated with a compound based on acetyl-methionine, inositol, cyanocobalamin, l-alanine, l-arginine, l-threonine, l-glutamic acid supplementation and α-lipoic acid) and third group (MON, n = 40 animals treated with monensin). Blood samples were collected from all cows at on 3 occasions pre-partum and 3 occasions post-partum. Body condition (BCS) score was evaluated and glucose, non-esterified fatty acids (NEFA), BHB, triglycerides, total cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltransferase (GGT), total bilirubin, total proteins, globulins, albumin and urea concentrations were assessed. Two-way repeated measures analysis of variance was applied. Statistically significant differences among the three experimental groups were found in the values of all studied parameters (P < 0.05). Our results confirm the established beneficial effect of MON treatment in decreasing BHB levels and increasing glucose availability after calving. Serum biochemical analysis revealed the expected post-partum alterations attributable to adaptations that influenced the metabolism and liver function in CTRL, whereas these alterations were reduced or absent in SUPP and MON. Results from the present study suggest that both preventive protocols, but in particular SUPP, could positively affect selected indicators of energy metabolism reducing the risk of hyperketonaemia and increase of liver function in Holstein dairy cows, both pre- and post-partum.

scholarly journals Elevated free fatty acids affect bovine granulosa cell function: a molecular cue for compromised reproduction during negative energy balance

2019 ◽  
Vol 8 (5) ◽  
pp. 493-505 ◽  
Author(s):  
Arpna Sharma ◽  
Vijay Simha Baddela ◽  
Frank Becker ◽  
Dirk Dannenberger ◽  
Torsten Viergutz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acids ◽  
Energy Balance ◽  
Free Fatty Acids ◽  
Dairy Cows ◽  
Combination Treatment ◽  
Follicular Fluid ◽  
Negative Energy

High-yielding dairy cows postpartum face the challenge of negative energy balance leading to elevated free fatty acids levels in the serum and follicular fluid thus affecting the ovarian function. Here, we investigated effects of physiological concentrations of palmitic acid (PA), stearic acid (SA) and oleic acid (OA) on the viability, steroid production and gene expression in a bovine granulosa cell (GC) culture model. Treatment with individual and combined fatty acids increased the CD36 gene expression, while no significant apoptotic effects were observed. Both PA and SA significantly upregulated the expression of FSHR, LHCGR, CYP19A1, HSD3B1, CCND2 and increased 17β-estradiol (E2) production, while OA downregulated the expression of these genes and reduced E2. Interestingly, STAR was equally downregulated by all fatty acids and combination treatment. E2 was significantly reduced after combination treatment. To validate the effects of OA, in vivo growing dominant follicles (10–19 mm) were injected with bovine serum albumin (BSA) with/without conjugated OA. The follicular fluid was recovered 48 h post injection. As in our in vitro model, OA significantly reduced intrafollicular E2 concentrations. In addition, expression of CD36 was significantly up- and that of CYP19A1 and STAR significantly downregulated in antral GC recovered from aspirated follicles. The ovulation rates of OA-injected follicles tended to be reduced. Our results indicate that elevated free fatty acid concentrations specifically target functional key genes in GC both in vitro and in vivo. Suggestively, this could be a possible mechanism through which elevated free fatty acids affect folliculogenesis in dairy cows postpartum.

1 CUMULUS CELLS PROTECT OOCYTES AGAINST POTENTIAL LIPOTOXICITY FROM ELEVATED FREE FATTY ACID CONCENTRATIONS IN FOLLICULAR FLUID

2013 ◽  
Vol 25 (1) ◽  
pp. 148
Author(s):  
H. Aardema ◽  
F. Lolicato ◽  
B. A. J. Roelen ◽  
P. L. A. M. Vos ◽  
J. B. Helms ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Follicular Fluid ◽  
Animal Health ◽  
Cumulus Cells ◽  
The Impact

Metabolic conditions characterized by elevated free fatty acid levels in the blood are often associated with reduced fertility performance. Increased concentrations of saturated free fatty acids can induce lipotoxicity in cumulus–oocyte-complexes in vitro, while unsaturated fatty acids like oleic acid are mostly harmless and able to counteract the impact of saturated fatty acids (Aardema et al. 2011 Biol. Reprod. 85, 62–69). This study investigates the impact of elevated free fatty acids in the blood on the follicular fluid and the lipid of cumulus and oocytes derived from these follicles. Furthermore, in vitro maturing oocytes were exposed to free fatty acid concentrations measured in follicles of control and metabolically stressed animals from this study to determine the impact on oocyte developmental competence. Cyclic heifers (n = 12) were synchronized (7 days CIDR®) and superstimulated from Day 10 of the synchronized cycle [4 days of Folltropin-V® (Bioniche Animal Health Inc., Belleville, ON, Canada) in decreasing doses; in total 200 mg]. Heifers received ad libitum grass silage, apart from the experimental group (n = 6), which was metabolically stressed during the period of superstimulation. Ovaries were collected by ovariectomy at final maturation, 22 h after the induced LH peak. Follicular fluids and cumulus–oocyte complexes (COC) were collected from follicles of ≥8 mm. To determine the free fatty acid and lipid composition, blood, follicular fluid, cumulus cells, and oocytes were analyzed with mass spectrometry. The COC (4 runs, 400 per group) derived from slaughterhouse ovaries were in vitro matured in a standard medium without or with the dominating free fatty acids, saturated palmitic and stearic and unsaturated oleic acid, in concentrations measured in follicular fluid of control (80, 70, and 100 µM) and experimental heifers (150, 100, and 200 µM) and fertilized and cultured until the blastocyst stage. Culture data were analyzed by one-way ANOVA and lipid data by two-sample t-test (P ≤ 0.05 considered significant). Procedures were approved by the Institutional Animal Care and Use Committee. Metabolic stress resulted in elevated free fatty acid levels in blood (from 430 ± 70 to 1048 ± 190 µM) and follicular fluid (from 357 ± 72 to 670 ± 133 µM), with relatively high oleic acid concentrations in follicular fluid (+10%). The increased levels of free fatty acids in follicular fluid resulted in a massive increase of fatty acids in the cumulus cells, but oocytes did only show marginal changes. In line with this, maturation in the presence of elevated palmitic, stearic, and oleic acid did not impair oocyte developmental competence and resulted in comparable blastocyst rates for the standard medium and the free fatty acid control and metabolic stress medium (31 ± 8.7, 34 ± 7.8, and 28 ± 1.7%). Thus, cumulus cells appear to protect oocytes against potential lipotoxicity from elevated free fatty acid concentrations by the accumulation of these fatty acids. This work was funded by Pfizer Animal Health.

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