scholarly journals Differential Transcript Profiles in Cumulus-Oocyte Complexes Originating from Pre-Ovulatory Follicles of Varied Physiological Maturity in Beef Cows

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 893
Author(s):  
Sarah E. Moorey ◽  
Jenna M. Monnig ◽  
Michael F. Smith ◽  
M. Sofia Ortega ◽  
Jonathan A. Green ◽  
...  
Keyword(s):  
Differentially Expressed Gene ◽  
Beef Cows ◽  
Physiological Status ◽  
Sequencing Data ◽  
Oocyte Competence ◽  
Induced Ovulation ◽  
Cumulus Oocyte Complex ◽  
Follicle Diameter ◽  
Gonadotropin Surge ◽  
Ovulatory Follicles

Small dominant follicle diameter at induced ovulation, but not at spontaneous ovulation, decreased pregnancy rate, fertilization rate, and day seven embryo quality in beef cows. We hypothesized that the physiological status of the follicle at GnRH-induced ovulation has a direct effect on the transcriptome of the Cumulus-Oocyte complex, thereby affecting oocyte competence and subsequent embryo development. The objective of this study was to determine if the transcriptome of oocytes and associated cumulus cells (CC) differed among small (≤11.7 mm) and large follicles (≥12.7 mm) exposed to a GnRH-induced gonadotropin surge and follicles (11.7–14.0 mm) exposed to an endogenous gonadotropin surge (spontaneous follicles). RNA sequencing data, from pools of four oocytes or their corresponding CC, revealed 69, 94, and 83 differentially expressed gene transcripts (DEG) among oocyte pools from small versus large, small versus spontaneous, and large versus spontaneous follicle classifications, respectively. An additional 128, 98, and 80 DEG were identified among small versus large, small versus spontaneous, and large versus spontaneous follicle CC pools, respectively. The biological pathway “oxidative phosphorylation” was significantly enriched with DEG from small versus spontaneous follicle oocyte pools (FDR < 0.01); whereas the glycolytic pathway was significantly enriched with DEG from CC pools obtained from large versus small follicles (FDR < 0.01). These findings collectively suggest that altered carbohydrate metabolism within the Cumulus-Oocyte complex likely contributes to the decreased competency of oocytes from small pre-ovulatory follicles exposed to an exogenous GnRH-induced gonadotropin surge.

147 EFFECT OF OVULATORY FOLLICLE DIAMETER ON THE OOCYTE TRANSCRIPTOME IN BEEF COWS

2016 ◽  
Vol 28 (2) ◽  
pp. 203
Author(s):  
S. E. Dickinson ◽  
J. A. Green ◽  
T. W. Geary ◽  
K. G. Pohler ◽  
G. A. Bridges ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Transcript Abundance ◽  
Beef Cows ◽  
Fetal Mortality ◽  
Physiological Status ◽  
Oocyte Competence ◽  
Follicle Diameter ◽  
Ovulatory Follicle ◽  
Prostaglandin F

Inadequate oocyte competence is a potential explanation for reduced pregnancy rates and(or) embryonic/fetal mortality when small dominant follicles are induced to ovulate prematurely with gonadotropin releasing hormone (GnRH). Our hypothesis was that the physiological status of an ovulatory follicle has a direct effect on competence of the oocyte and resulting embryo. The objective was to determine if the transcriptome of oocytes differ depending on whether they are collected from small or large dominant follicles following a GnRH-induced gonadotropin surge. Suckled beef cows (n = 350) were pre-synchronized with a 5-day CIDR protocol. Following pre-synchronization, GnRH1 was administered on Day –9, prostaglandin F on Day –2, GnRH2 (to initiate the ovulatory process) on Day 0, and dominant follicles were transvaginally aspirated on Day 1 before follicular rupture. On Day 0, cows were divided into small (<11.7 mm; no oestrus expression), or large (>12.5 mm; no oestrus expression) groups based on dominant follicle diameter. Oocytes were individually collected after aspiration, and RNA was later extracted from pools of 4 oocytes (n = 6 oocyte pools from both small and large follicles) and sequenced on an Illumina HiSEqn 2000 (single reads, 100 bases; Illumina Inc., San Diego, CA, USA). The sequences were tiled against a ~23 500 member bovine transcript reference obtained from the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). Tiling to target transcripts required a minimum match of 50 bases with at least 96% identity. Tiling counts were displayed as reads per kilobase of transcript per million mapped reads (RPKM) values, which were obtained by correcting for the length of each target (in kb) and the number of total tiled reads (in millions). Differences between groups were defined by two-tailed t-test and gene lists were selected based on P-values <0.02. Numerous differences in transcript abundance were characterised between oocytes from small and large dominant follicles. Follistatin-like 5 expression was increased (P < 0.02) in oocytes collected from large dominant follicles compared with oocytes collected from small dominant follicles. Several genes were associated with the ubiquitin pathway (e.g. ubiquitin conjugating enzyme, ubiquitin like protein-7) and were up-regulated (P < 0.02) in oocytes from large versus small dominant follicles. In addition, 4 members of the zinc finger protein family were up-regulated (P < 0.02) and 4 members were down-regulated (P < 0.02) in oocytes from large compared with small dominant follicles. In summary, some of the genes that were highly differentially regulated in bovine oocytes between small and large dominant follicles included members of the zinc finger and ubiquitin pathways, which may reflect differences in transcriptional regulation and protein turnover, respectively, between oocytes collected from large and small follicles. Study was supported by AFRI Grant no. 2013–67015–21076 from the USDA National Institute of Food and Agriculture (Washington, DC).

scholarly journals Effect of preovulatory follicle size on cumulus cell and follicular wall transcript abundance in beef cows

2017 ◽  
Author(s):  
◽  
Jenna Marie Monnig
Keyword(s):  
Cumulus Cell ◽  
Cumulus Cells ◽  
Beef Cows ◽  
Preovulatory Follicle ◽  
Dominant Follicle ◽  
Oocyte Competence ◽  
Follicle Diameter ◽  
Follicle Size ◽  
Gonadotropin Surge ◽  
Cell Transcriptome

Gonadotropin releasing hormone (GnRH)-induced ovulation of small dominant follicles decreased pregnancy rates and increased late embryonic/fetal mortality in postpartum beef cows, which could be caused by inadequate oocyte competence and(or) maternal environment. Previous studies revealed that dominant follicle size at GnRHinduced ovulation in beef cows may affect oocyte competence, as higher fertilization rates and higher embryo quality were achieved as dominant follicle diameter at insemination increased. In addition, higher pregnancy rates and increased concentrations of circulating preovulatory estradiol and postovulatory progesterone were observed in recipient cows induced to ovulate large compared to small dominant follicles, which may affect the establishment of pregnancy. The objectives of the current study were to determine the effects of preovulatory follicle size and physiological status on the cumulus cell transcriptome (Experiment 1) and determine the effects of preovulatory follicle size and steroidogenic capacity (i.e. concentrations of circulating estradiol) on the dominant follicle wall transcriptome collected before the preovulatory gonadotropin surge (Experiment 2). In Experiment 1, ovulation was synchronized in suckled beef cows by administering an injection of GnRH on d-9, prostaglandin F2a (PG) on d-2, and a second injection of GnRH on d0. The dominant follicle was trans-vaginally aspirated on d1 and cumulus-oocyte complexes (COC) were collected. The cumulus cells were removed from the oocytes and assigned to one of the following follicle classifications based on follicle diameter and estrus expression: small (n=6; less than 11.7mm; no estrus expression), large (n=6; greater than 12.5 mm; no estrus expression), or spontaneous (n=5; 11.6-13.9 mm; estrus expression and endogenous gonadotropin surge). RNA was extracted from cumulus cells collected from pools of four oocytes and sequenced before being aligned to the Bos taurus genome (UMD3.1). When comparing the cumulus cell transcriptome of small versus large preovulatory follicles, 430 transcripts were more abundant at a false discovery rate (FDR) less than 0.10 in small follicles and 454 were more abundant in large follicles. The glycolytic pathway was enriched in the cumulus cells of large follicles compared to small follicles. In the small versus spontaneous preovulatory follicle comparison, 597 transcripts were more abundant in small follicles and 1012 transcripts were more abundant in spontaneous follicles. The steroid biosynthesis pathway (i.e. cholesterol synthesis) was enriched in the cumulus cells of spontaneous compared to small follicles. In the large versus spontaneous preovulatory follicle comparison, 541 transcripts were more abundant in cumulus cells from large follicles and 951 were more abundant in cumulus cells from spontaneous follicles. In summary, a greater abundance of transcripts encoding for members of the glycolytic pathway in large follicles and transcripts encoding for members of the steroid biosynthesis pathway in the cumulus cells of spontaneous compared to small follicles indicate that oocytes from small follicles may be less competent. Preovulatory follicle development was synchronized in Experiment 2 by administering GnRH on d-9 and PG on d-2 to non-lactating beef cows. The ovaries were harvested at slaughter 48 hr after PG (d0) and the dominant follicle collected. RNA was extracted from approximately half of the follicle wall and sequenced. Cows were divided into two classifications based on dominant follicle diameter at collection: small (n=4; less than 11.5 mm) and large (n=7; greater than 12.5 mm). Nine transcripts were more abundant in small follicles, and two transcripts were more abundant in large follicles. No significant pathways were found. The same 11 follicle walls were also divided into two classifications based on concentration of serum estradiol at 48 hr after PG: low (n=6; less than 4.0 pg/ml) and high (n=5; greater than or equal to 4.0 pg/ml). In the low estradiol classification, 281 transcripts were more abundant in the follicle wall and 40 were more abundant in the follicle wall of the high estradiol classification. No significant pathways were found. Transcripts were analyzed with PANTHER to find significant gene ontology (GO) terms. Differentially abundant transcripts in low estradiol follicles were more highly associated with mitosis, chromosome segregation, and regulation of biological processes. In summary, a small number of transcripts were differentially abundant in the follicle wall of small versus large dominant follicles prior to the preovulatory gonadotropin surge and no specific pathways were identified that might provide insight into how the physiological maturity of a dominant follicle can affect pregnancy rate. Comparisons made between follicle walls from follicles with low or high serum estradiol found a larger number of transcripts were more highly abundant in the low estradiol follicles, possibly indicating that a higher level of transcription is taking place in the low estradiol follicles, and therefore are less mature.

scholarly journals Correlation between Pre-Ovulatory Follicle Diameter and Follicular Fluid Metabolome Profiles in Lactating Beef Cows

Metabolites ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 623
Author(s):  
Casey C. Read ◽  
Lannett Edwards ◽  
Neal Schrick ◽  
Justin D. Rhinehart ◽  
Rebecca R. Payton ◽  
...  
Keyword(s):  
Follicular Fluid ◽  
Cumulus Cells ◽  
Beef Cows ◽  
Pathway Enrichment Analysis ◽  
Induced Ovulation ◽  
Follicle Diameter ◽  
Ovulatory Follicle ◽  
Altered Glucose ◽  
Embryo Cleavage ◽  
Ovulatory Follicles

Induced ovulation of small pre-ovulatory follicles reduced pregnancy rates, embryo survival, day seven embryo quality, and successful embryo cleavage in beef cows undergoing fixed-time artificial insemination. RNA-sequencing of oocytes and associated cumulus cells collected from pre-ovulatory follicles 23 h after gonadotropin-releasing hormone (GnRH) administration to induce the pre-ovulatory gonadotropin surge suggested reduced capacity for glucose metabolism in cumulus cells of follicles ≤11.7 mm. We hypothesized that the follicular fluid metabolome influences metabolic capacity of the cumulus-oocyte complex and contributes to reduced embryo cleavage and quality grade observed following induced ovulation of small follicles. Therefore, we performed a study to determine the correlation between pre-ovulatory follicle diameter and follicular fluid metabolome profiles in lactating beef cows (Angus, n = 130). We synchronized the development of a pre-ovulatory follicle and collected the follicular contents approximately 20 h after GnRH administration. We then performed ultra-high performance liquid chromatography—high resolution mass spectrometry (UHPLC-HRMS) metabolomic studies on 43 follicular fluid samples and identified 38 metabolites within pre-ovulatory follicles of increasing size. We detected 18 metabolites with a significant, positive correlation to follicle diameter. Individual and pathway enrichment analysis of significantly correlated metabolites suggest that altered glucose and amino acid metabolism likely contribute to reduced developmental competence of oocytes when small pre-ovulatory follicles undergo induced ovulation.

Effect of Ovulatory Follicle Size on Steroidogenic Capacity and Molecular Markers of Oocyte Competence prior to GnRH-Induced Ovulation in Nonlactating Beef Cows.

2012 ◽  
Vol 87 (Suppl_1) ◽  
pp. 492-492
Author(s):  
Ky G. Pohler ◽  
Michael F. Smith ◽  
Emma M. Jinks ◽  
Fernanda M. Abreu ◽  
Crystal A. Roberts ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Beef Cows ◽  
Oocyte Competence ◽  
Induced Ovulation ◽  
Ovulatory Follicle ◽  
Follicle Size

Evaluation of oocyte quality: morphological, cellular and molecular predictors

2007 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Qiang Wang ◽  
Qing-Yuan Sun
Keyword(s):  
Transforming Growth Factor ◽  
Polar Body ◽  
Morphological Characteristics ◽  
Transforming Growth Factor Β ◽  
Oocyte Quality ◽  
Developmental Competence ◽  
Meiotic Spindle ◽  
Oocyte Competence ◽  
Cumulus Oocyte Complex ◽  
Glucose 6 Phosphate Dehydrogenase

Mounting evidence that oocyte quality profoundly affects fertilisation and subsequent embryo development drives the continued search for reliable predictors of oocyte developmental competence. In the present review, we provide an overall summary and analysis of potential criteria that can be used to evaluate oocyte quality. These criteria are specifically classified as morphological and cellular/molecular predictors. Traditional methods for the evaluation of oocyte quality are based on morphological classification of the follicle, cumulus–oocyte complex, polar body and/or meiotic spindle. Although the use of morphological characteristics as predictors of oocyte quality is controversial, such a grading system can provide valuable information for the preselection of oocytes with higher developmental competence and, therefore, may maximise embryo developmental outcome. Several intrinsic markers (such as mitochondrial status and glucose-6-phosphate dehydrogenase l activity) and extrinsic markers (such as apoptosis of follicular cells and levels of the transforming growth factor-β superfamily in follicular fluid or serum) have also been reported as useful indicators of oocyte competence and embryo quality. Compared with the morphological parameters, these cellular and molecular predictors of oocyte quality may prove to be more precise and objective, although further studies and refinement of techniques are needed.

scholarly journals Oocyte Competence Biomarkers Associated With Oocyte Maturation: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Batara Sirait ◽  
Budi Wiweko ◽  
Ahmad Aulia Jusuf ◽  
Dein Iftitah ◽  
R. Muharam
Keyword(s):  
Oocyte Maturation ◽  
Blastocyst Stage ◽  
Current Approach ◽  
Developmental Competence ◽  
Matrix Remodeling ◽  
Oocyte Competence ◽  
Nuclear Maturation ◽  
Oocyte Developmental Competence ◽  
Cumulus Oocyte Complex

Oocyte developmental competence is one of the determining factors that influence the outcomes of an IVF cycle regarding the ability of a female gamete to reach maturation, be fertilized, and uphold an embryonic development up until the blastocyst stage. The current approach of assessing the competency of an oocyte is confined to an ambiguous and subjective oocyte morphological evaluation. Over the years, a myriad of biomarkers in the cumulus-oocyte-complex has been identified that could potentially function as molecular predictors for IVF program prognosis. This review aims to describe the predictive significance of several cumulus-oocyte complex (COC) biomarkers in evaluating oocyte developmental competence. A total of eight acclaimed cumulus biomarkers are examined in the study. RT-PCR and microarray analysis were extensively used to assess the significance of these biomarkers in foreseeing oocyte developmental competence. Notably, these biomarkers regulate vital processes associated with oocyte maturation and were found to be differentially expressed in COC encapsulating oocytes of different maturity. The biomarkers were reviewed according to the respective oocyte maturation events namely: nuclear maturation, apoptosis, and extracellular matrix remodeling, and steroid metabolism. Although substantial in vitro evidence was presented to justify the potential use of cumulus biomarkers in predicting oocyte competency and IVF outcomes, the feasibility of assessing these biomarkers as an add-on prognostic procedure in IVF is still restricted due to study challenges.

Fertility in estrus-cycling and noncycling virgin heifers and suckled beef cows after induced ovulation.

1997 ◽  
Vol 75 (5) ◽  
pp. 1343 ◽  
Author(s):  
J S Stevenson ◽  
D P Hoffman ◽  
D A Nichols ◽  
R M McKee ◽  
C L Krehbiel
Keyword(s):  
Beef Cows ◽  
Induced Ovulation

10 TIMED ARTIFICIAL INSEMINATION PROTOCOLS TO SYNCHRONIZATION OF OVULATION IN BOS TAURUS TAURUS SUCKLING BEEF COWS

2015 ◽  
Vol 27 (1) ◽  
pp. 97
Author(s):  
G. A. Pessoa ◽  
A. P. Martini ◽  
J. M. Trentin ◽  
D. R. Dotto ◽  
H. L. D. Neri ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Body Condition Score ◽  
Animal Health ◽  
Beef Cows ◽  
Treated Group ◽  
Conception Rate ◽  
Plasma Progesterone ◽  
Follicle Diameter ◽  
Condition Score ◽  
South Of Brazil

The aim of this study was to compare 3 methods for synchronization of ovulation in anestrous beef cows. The hypothesis of this study was to determine whether low doses of hCG has superior efficacy to cypionate to induce ovulation in anestrous cows and provide higher pregnancy rate in oestrus-synchronization programs. Synchronization of ovulation and conception rate to timed AI (TAI) were evaluated in anestrus Bos taurus taurus suckling beef cows 45 ± 15 days postpartum and with body condition score of 2.9 (1 to 5) maintained in a native pastured system in the south of Brazil. Females were evaluated with ultrasound on the Day 0 (D0) of the protocol (Day 0), day 8 (D8), immediately before TAI (D10), and 7 days after TAI (Day 17). All cows were synchronized with an intravaginal progesterone-releasing device (IPRD; 0.75 g of progesterone, Prociclar®, Hertape Calier Animal Health, Juatuba, Brazil) and 2 mg IM of oestradiol benzoate (EB; Benzoato HC®) on D0. On Day 8, the IPRD was removed and 150 μg of D (+) cloprostenol (Veteglan Luteolytic®), and 25 IU IM FSH/LH (Pluset®) were administered. Females of the EC (n = 84) group received 1 mg IM of oestradiol cypionate (EC; Cipionato HC®). Females on D8 of the hCG (n = 81) group received 500 IU IM of hCG (Vetecor®, Hertape Calier) at the time of TAI. The females of the EC + hCG group (n = 83) received both treatments. All cows were submitted to TAI 54 h after withdrawal of IPRD. A part of the cows (n = 102) had the ovulation evaluated every 12 h from the withdrawal of IPRD [EC (n = 34), hCG (n = 34), and hCG + EC (n = 33)]. Statistical analysis was performed using SAS PROC GLIMMIX. The dominant follicle diameter (FD) on Day 8 (8.7 ± 0.2, 8.8 ± 0.2, 8.6 ± 0.2) did not differ between treatments EC, EC + hCG, or hCG (P = 0.79). However, the FD on D10 was higher (P = 0.001) for cows treated with hCG (12.9 ± 0.3) compared with cows from the EC (11.3 ± 0.2) or EC + hCG group (11.8 ± 0.2). The interval (h) between the withdrawal of IPRD and ovulation was lower (P = 0.01) for the hCG group, (71.2 ± 1.7) compared with the groups treated with EC or EC + hCG (76.6 ± 2.18 and 74.2 ± 1.65), respectively. The ovulation rate did not differ (P = 0.61) among the EC (85.2%, 29/34), hCG (91.1%, 31/34), or EC + hCG groups (90.9%, 30/33). Corpus luteum diameter (mm) was higher (P = 0.04) on D17 for the hCG-treated group (21.4 ± 0.3) compared with others treatments (EC = 19.1 ± 0.8 or EC + hCG = 20.4 ± 0.8). However, the plasma progesterone levels on D17 were EC = 2.0 ± 0.1, hCG = 2.4 ± 0.1, and EC + hCG = 2.3 ± 0.1 ng mL–1 (P = 0.19), and the conception rate on the 28th day after TAI (EC = 43.0%; hCG = 47.0%, and EC + hCG = 48.8%; P = 0.76) was also similar. The hCG determined smallest ovulation interval, but similar rates of pregnancy were observed with both treatments.

Influence of a short-term prepartum supplementation on beef cows and calves’ performance in pastoral conditions

2016 ◽  
Vol 56 (11) ◽  
pp. 1913 ◽  
Author(s):  
G. Quintans ◽  
A. Scarsi ◽  
G. Roig ◽  
M. Carriquiry ◽  
G. Banchero
Keyword(s):  
Milk Production ◽  
Postpartum Period ◽  
Crude Protein ◽  
Beef Cows ◽  
Breeding Period ◽  
Serum Progesterone ◽  
Follicle Diameter ◽  
Acid Detergent Fibre ◽  
Calf Performance ◽  
Sorghum Grain

Multiparous Aberdeen Angus × Hereford crossbred cows were used to evaluate the effect of supplementation during the last month of gestation on milk production and composition and cow and calf performance. Cows were assigned randomly to supplement (SUP; n = 18) or Control (CON; n = 17) treatments. Supplemented cows were offered (1 kg/100 kg bodyweight) a mix of sorghum grain and protein concentrated (67 : 33 as-fed basis; 16% crude protein, 11% acid detergent fibre) from (mean ± s.e.m.) 33 ± 1.4 days prepartum until calving. Before, during, and after the supplementation period, cows grazed together a native pasture paddock with average forage mass available of 1345 kg/ha of dry matter (10.4% crude protein, 45.2% acid detergent fibre). Cows were blood sampled weekly from –42 to 112 days postpartum (DPP) for serum progesterone and non-esterified fatty acids (NEFA) concentrations. Maximum follicle diameter was measured by ovarian ultrasound examination at 60 DPP. The breeding period lasted 60 days and started at 60 ± 1.4 DPP. There was an interaction between treatment and time on BCS (P < 0.0005). Before calving there were no differences in BCS between cows in SUP and in CON, but at calving SUP cows tended (P = 0.10) to present greater BCS and from calving to 84 DPP BCS was greater (P < 0.05) in SUP with respect to CON cows. There was an interaction between treatment and time on plasma NEFA concentrations (P < 0.0005). During the last month of gestation NEFA concentrations were reduced in SUP cows but there were no differences between treatments during the postpartum period. Milk production decreased linearly from 30 to 150 DPP but there was no effect of treatment on it. Calf bodyweight at birth and at weaning did not differ between treatments (37.5 ± 2.4 and 175.6 ± 2.4 kg, respectively). The probability of cows presenting follicles with diameter ≥10 mm was greater (P < 0.05) in SUP than CON cows. The length of the postpartum period did not differ between treatments. The probability of cows cycling during the first 90 DPP and pregnancy rate tended (P = 0.08) to be greater in SUP than in CON cows. Supplementation in winter and for only 30 days in the last month of gestation of beef cows under grazing conditions, increased cows’ BCS without increasing BW of calves, and tended to improve reproductive performance.

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