Search

The present study examined whether the effects of dietary-induced hyperlipidaemia on preimplantation embryo development depend on the predominant fatty acid (FA) type in the diet. In a combined in vivo-in vitro bovine model, two groups of cows (n≤3 in each group) were fed with three diets consecutively (4 weeks feeding for each) (1) a maintenance control diet (CONT); (2) a high-starch diet rich in saturated fat (SAT); and (3) a high-starch diet rich in omega-3 unsaturated fat (UNSAT). Two feeding sequences were used to test for carry-over effects Group A was fed CONT, SAT1 and then UNSAT2, whereas Group B was fed CONT, UNSAT1 and then SAT2. Serum was collected after each dietary period, analysed and tested in bovine in vitro embryo culture. Introducing SAT and UNSAT diets induced hyperlipidaemia (specifically hypercholesterolaemia and elevated free FAs) and reduced insulin sensitivity. Carry-over effects in serum metabolites and FA profile were dependent on the diet and feeding sequence. SAT1 and SAT2 serum decreased blastocyst rates and altered blastocyst mRNA expression related to apoptosis and oxidative stress. UNSAT1 and UNSAT2 serum resulted in normal embryo development and quality. Other in vitro effects depended on the sequence of feeding. In conclusion, substitution of saturated fat with omega-3 fat in a high-caloric diet induced hyperlipidaemia with an FA profile yielding similar rates and quality of blastocysts compared with normolipidaemic controls. © CSIRO 2017.

Lipolytic metabolic conditions are traditionally associated with elevated non-esterified fatty acid (NEFA) concentrations, but may also be accompanied by hyperglycaemia in obesity or by hypoglycaemia during a negative energy balance status. Elevated NEFA concentrations disrupt oocyte and embryo development and quality, but little is known about whether the effects of lipolytic conditions on oocyte developmental competence are modulated by glucose availability. To answer this, bovine cumulus-oocyte complexes (COCs) were matured under different conditions physiological NEFA (72M) and normal glucose (5.5mM), pathophysiologically high NEFA (420M) and normal glucose, high NEFA and high glucose (9.9mM), high NEFA and low glucose (2.8mM). Developmental potential, cumulus expansion and metabolism of COCs exposed to high NEFA and low glucose were affected to a greater extent compared with COCs matured under high NEFA and high glucose conditions. High NEFA and high glucose conditions caused a moderate increase in oocyte reactive oxygen species compared with their high NEFA and low glucose or control counterparts. Blastocyst metabolism and the transcriptome of metabolic and oxidative stress-related genes were not affected. However, both lipolytic conditions associated with hyper-or hypoglycaemia led to surviving embryos of reduced quality with regards to apoptosis and blastomere allocation.

In this study, the hypothesis that embryo development during routine IVF procedures is determined by the pre-ovulatory follicular fluid composition was tested. Follicular fluid from women with obesity ('obese') and a 'positive' or 'negative' IVF outcome was added during the in-vitro maturation of bovine oocytes. 'Negative' and 'obese' follicular fluid reduced bovine embryo development, compared with laboratory control embryo development (P < 0.05 or P < 0.1). The addition of follicular fluid also altered bovine blastocyst gene expression. Furthermore, LDHA and PPARGC1B gene expression differed between follicular fluid groups. Data suggest that pre-ovulatory follicular fluid can potentially affect oocyte developmental competence and embryo quality. Furthermore, the bovine model may be used as a screening tool. © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Maternal metabolic disorders linked to lipolysis are major risk factors for reproductive failure. A notable feature of such disorders is increased non-esterified fatty acid (NEFA) concentrations in the blood, which are reflected in the ovarian follicular fluid. Elevated NEFA concentrations impact on the maturing oocyte and even alter subsequent embryo physiology. The aetiological mechanisms have not been fully elucidated. Therefore, in the present study, bovine in vitro maturing cumulus-oocyte complexes were exposed (24h) to three different maturation treatments containing (1) physiological (72 M) NEFA concentrations (≤control); (2) elevated (75 M) stearic acid (SA) concentrations (≤HIGH SA); and (3) elevated (425 M) NEFA concentrations (≤HIGH COMBI). Zygotes were fertilised and cultured following standard procedures. Transcriptomic analyses in resulting Day 7.5 blastocysts revealed that the major pathways affected are related to lipid and carbohydrate metabolism in HIGH COMBI embryos and to lipid metabolism and cell death in HIGH SA embryos. Furthermore, lower glutathione content and a reduced number of lipid droplets per cell were observed in HIGH SA-exposed oocytes and resulting morulae, respectively, compared with their HIGH COMBI-exposed counterparts. Vitrified embryos originating from HIGH SA-exposed oocytes tended to exhibit lower survival rates compared with controls. These data suggest possible mechanisms explaining why females across species suffering lipolytic disorders experience difficulties in conceiving. � 2015 CSIRO.

Objective To study how long-term elevated non-esterified fatty acid (NEFA) concentrations, typical in metabolic disorders such as obesity or type 2 diabetes, affect murine follicular development, follicle quality, and subsequent oocyte developmental competence in vitro. Design Experimental study. Setting In vitro culture setting. Animal(s) Female and male 13-day old, B6CBAF1 mice of proven fertility were sacrificed for harvesting ovaries and epididymal sperm, respectively. Intervention(s) Early secondary murine follicles were cultured in vitro in the presence of NEFAs until the antral stage (12 days). Treatments consisted of one or a mixture of NEFAs (stearic acid [SA], palmitic acid [PA], oleic acid [OA]) in physiological (basal) or pathological (high SA, high OA, high NEFA) concentrations. Main Outcome Measure(s) Follicular development; follicle and oocyte diameters; secretion of progesterone, estradiol, and inhibin B; and luteinized granulosa cell gene expression patterns were investigated. Oocytes from NEFA-exposed follicles were fertilized in vitro, and presumptive zygotes were cultured until the blastocyst stage. Result(s) Exposure to high SA reduced follicle diameters and day-12 antrum formation. Elevated NEFA concentrations changed luteinized granulosa cell messenger-ribonucleic acid abundance of genes related to energy/fatty acid/steroid metabolism, apoptosis, and oxidative stress. High NEFA and high SA treatments increased progesterone synthesis, compared with high OA follicles. Oocyte developmental competence was substantially reduced in oocytes retrieved from high OA-, high SA-, and high NEFA-exposed follicles compared with basal-treated follicles. Conclusion(s): This study showed, for the first time, that lipolysis-linked, elevated NEFA concentrations can potentially impair fertility, by altering follicular physiology and reducing oocyte developmental competence. © 2014 by American Society for Reproductive Medicine.

Elevated plasma nonesterified fatty acid (NEFA) concentrations are associated with negative energy balance and metabolic disorders such as obesity and type II diabetes. Such increased plasma NEFA concentrations induce changes in the microenvironment of the ovarian follicle, which can compromise oocyte competence. Exposing oocytes to elevated NEFA concentrations during maturation affects the gene expression and phenotype of the subsequent embryo, notably prompting a disrupted oxidative metabolism. We hypothesized that these changes in the embryo are a consequence of modified energy metabolism in the oocyte. To investigate this, bovine cumulus oocyte complexes were matured under elevated NEFA conditions, and energy metabolism-related gene expression, mitochondrial function, and ultrastructure evaluated. It was found that expression of genes related to REDOX maintenance was modified in NEFA-exposed oocytes, cumulus cells, and resultant blastocysts. Moreover, the expression of genes related to fatty acid synthesis in embryos that developed from NEFA-exposed oocytes was upregulated. From a functional perspective, inhibition of fatty acid b-oxidation in maturing oocytes exposed to elevated NEFA concentrations restored developmental competence. There were no clear differences in mitochondrial morphology or oxygen consumption between treatments, although there was a trend for a higher mitochondrial membrane potential in zygotes derived from NEFA-exposed oocytes. These data show that the degree of mitochondrial fatty acid b-oxidation has a decisive impact on the development of NEFA-exposed oocytes. Furthermore, the gene expression data suggest that the resulting embryos adapt through altered metabolic strategies, which might explain the aberrant energy metabolism previously observed in these embryos originating from NEFA-exposed maturing oocytes. © 2013 Society for Reproduction and Fertility.

Reduced oocyte and embryo quality are recognised as major factors in the problem of disappointing fertility in high producing dairy cows. This review aims to shed more light on the importance of the intrafollicular environment in the subfertility problem in dairy cows. Metabolic disturbances associated with negative energy balance (NEB) early postpartum are associated with ovarian dysfunction. Changes in the growth pattern of the ovarian follicle during a period of NEB can indirectly affect oocyte quality. Furthermore, a maternal metabolic disorder (linked with NEB or nutritionally induced) may alter the endocrine and biochemical composition of the follicular fluid, the micro-environment of the growing and maturing female gamete. The maturing oocyte is very sensitive to any perturbation in its direct environment and in vitro maturation models revealed that some of these metabolic changes reduce the oocyte's developmental competence. Also, embryo quality is significantly reduced due to maturation in adverse conditions. Well balanced and timed oocyte metabolism and gene expression are crucial to safeguard an optimal oocyte development. In that perspective, metabolome and transcriptome parameters of the oocyte may serve to predict reproductive success rates. Finally, there is growing evidence that adverse conditions for oocyte growth and maturation may also jeopardise the health and performance of the offspring. © IETS 2012.

Elevated concentrations of serum non-esterified fatty acids (NEFA), associated with maternal disorders such as obesity and type II diabetes, alter the ovarian follicular micro-environment and have been associated with subfertility arising from reduced oocyte developmental competence. We have asked whether elevated NEFA concentrations during oocyte maturation affect the development and physiology of zygotes formed from such oocytes, using the cow as a model. The zygotes were grown to blastocysts, which were evaluated for their quality in terms of cell number, apoptosis, expression of key genes, amino acid turnover and oxidative metabolism. Oocyte maturation under elevated NEFA concentrations resulted in blastocysts with significantly lower cell number, increased apoptotic cell ratio and altered mRNA abundance of DNMT3A, IGF2R and SLC2A1. In addition, the blastocysts displayed reduced oxygen, pyruvate and glucose consumption, up-regulated lactate consumption and higher amino acid metabolism. These data indicate that exposure of maturing oocytes to elevated NEFA concentrations has a negative impact on fertility not only through a reduction in oocyte developmental capacity but through compromised early embryo quality, viability and metabolism. © 2011 Van Hoeck et al.

Background Obesity is associated with female reproductive abnormalities. Hyperlipidaemia might alter the embryonic micro-environment and potentially result in reduced fertility. We aimed to induce hyperlipidaemia nutritionally and investigate the consequences of hyperlipidaemic culture conditions on bovine in vitro embryo development, embryo quality and gene expression patterns. Methods Bovine zygotes (n = 1545) were cultured in synthetic oviductal fluid medium supplemented with serum from heifers (n = 3), each fed three successive dietary treatments (i) control serum, following a hay-based diet, (ii) hyperlipidaemic serum, following a carbohydrate and protected palm-oil-rich diet (FatCh) or (iii) hyperlipidaemic serum, following a protected palm-oil-rich diet (Fat). Blastocysts were evaluated for development, cell count, picnotic and mitotic indexes and cryotolerance. Selected mRNA transcripts were measured by quantitative RT-PCR. Results FatCh and Fat diets approximately doubled the total cholesterol concentrations, compared with controls (167.1 ± 11.9, 150.0 ± 12.8 versus 83.4 ± 13.7 mg/dl, respectively, P < 0.05), and fatty acid concentrations (8146.60 ± 214.61, 6935.56 ± 1081.04 versus 3944.0 ± 425.07 mol/l, respectively, P < 0.05). Supplementation of culture media with FatCh and Fat serum significantly reduced blastocyst rates, compared with controls (27.8, 23.4 versus 36.2, respectively, P < 0.01), total cell number (103.3 ± 30.1, 95.6 ± 28.2 versus 146.9 ± 34.2, respectively, P < 0.01), mitotic index (1.3 ± 1.1, 1.7 ± 2.4 versus 3.6 ± 2.2, respectively, P < 0.01) and hatching rates after vitrification (20.4, 13.8 versus 35.7, respectively, P = 0.03). Embryos in FatCh and Fat groups exhibited significantly higher mRNA levels for genes related to apoptosis and metabolism, compared with controls. Conclusion SThis combined in vivo and in vitro model indicates that the exposure of preimplantation embryos to hyperlipidaemic conditions may result in reduced embryo

The feasibility of repeated collection and enzymatic isolation of large numbers of viable primordial and primary follicles from living donor cows were tested. Ovarian cortical biopsies were collected transvaginally by the Biopsy Pick-Up (BPU) device, a modi. cation of an Ovum Pick-Up instrument. Follicles were enzymatically isolated from the retrieved cortical tissue samples, and follicle viability was determined by a live/dead. fluorescent assay. Six cows were subjected to BPU once per week during 4 consecutive weeks, and in each BPU session 4 cortical tissue samples were collected per ovary. Over the 4-week trial period, a total of 1443 primordial and primary follicles were collected, 1358 (94%) of which were primordial and 85 (6%) were primary follicles. In each BPU session, an average 60.1 +/- 10.7 (mean +/- SEM) primordial and primary follicles were isolated per cow. The number of follicles varied considerably throughout the trial period and between cows. Statistical analysis of the data, however, did not support the presence of any distinct trends in the follicle yields over time or between cows. A total of 111 enzymatically isolated follicles were analyzed for viability with fluorescent probes. The vast majority of isolated follicles (92.8%) were totally viable. We conclude that the standardized BPU procedure generates sufficiently large numbers of vital primordial and primary follicles, thus validating BPU as a new tool for research into early bovine follicular development.