Reduced ovarian follicular development as a consequence of low body condition in ewes

1987 ◽  
Vol 115 (1) ◽  
pp. 75-83 ◽  
Author(s):  
A. S. McNeilly ◽  
J. A. Jonassen ◽  
S. M. Rhind
Keyword(s):  
Body Condition ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Lower Proportion ◽  
Ovulation Rate ◽  
Luteal Regression ◽  
Ovarian Follicular Development ◽  
Ovulatory Follicles ◽  
Fluid Levels ◽  
Oestradiol Production

Abstract. The effect of body condition on ovarian follicular development was investigated in Scottish Blackface ewes in high and low body condition. Follicles were dissected from ovaries on days 11 and 12 of the luteal phase and 24 h after prostaglandin-induced luteal regression. Ewes in low body condition had a lower ovulation rate (low: 0.9; high: 1.8 P < 0.05) and lower mean plasma levels of FSH during both the luteal (low: 54; high: 72 μg/l) and follicular (low: 34; high: 43 μg/l) phases of the cycle. Low body condition was associated with a reduced number of large (⩾ 4 mm) follicles in both the luteal and follicular phases, and in low condition a lower proportion of these follicles was oestrogenic and potentially ovulatory as assessed by follicular fluid levels of oestradiol. However, within the different oestrogenic classifications of these large follicles there were no significant differences in the steroidogenic capacity as assessed by the concentrations of either oestradiol or testosterone in follicular fluid, basal and hCG-stimulated testosterone production, thecal 125I hCG binding or basal and testosterone-stimulated oestradiol production by granulosa cells in relation to body condition. These results suggest that body condition influences ovulation rate by altering the concentration of FSH in blood, which in turn affects the number of potentially ovulatory follicles growing beyond 4 mm.

Ovarian follicular development during the follicular phase of oestrous cycle in manchega ewes with different ovulation rate

1996 ◽  
Vol 45 (1) ◽  
pp. 299 ◽  
Author(s):  
A.Gómez Brunet ◽  
A.López Sebastián ◽  
A.González de Bulnes ◽  
J.Santiago Moreno ◽  
M.García López
Keyword(s):  
Follicular Development ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Ovarian Follicular Development

Regulation of folliculogenesis and the determination of ovulation rate in ruminants

2011 ◽  
Vol 23 (3) ◽  
pp. 444 ◽  
Author(s):  
R. J. Scaramuzzi ◽  
D. T. Baird ◽  
B. K. Campbell ◽  
M.-A. Driancourt ◽  
J. Dupont ◽  
...  
Keyword(s):  
Follicular Development ◽  
Oocyte Quality ◽  
Ovulation Rate ◽  
Fetal Life ◽  
Cellular Events ◽  
Sequence Of Events ◽  
Reproductive Cycles ◽  
Ovulatory Follicles ◽  
Original Concept

The paper presents an update of our 1993 model of ovarian follicular development in ruminants, based on knowledge gained from the past 15 years of research. The model addresses the sequence of events from follicular formation in fetal life, through the successive waves of follicular growth and atresia, culminating with the emergence of ovulatory follicles during reproductive cycles. The original concept of five developmental classes of follicles, defined primarily by their responses to gonadotrophins, is retained: primordial, committed, gonadotrophin-responsive, gonadotrophin-dependent and ovulatory follicles. The updated model has more extensive integration of the morphological, molecular and cellular events during folliculogenesis with systemic events in the whole animal. It also incorporates knowledge on factors that influence oocyte quality and the critical roles of the oocyte in regulating follicular development and ovulation rate. The original hypothetical mechanisms determining ovulation rate are retained but with some refinements; the enhanced viability of gonadotrophin-dependent follicles and increases in the number of gonadotrophin-responsive follicles by increases in the throughput of follicles to this stage of growth. Finally, we reexamine how these two mechanisms, which are thought not to be mutually exclusive, appear to account for most of the known genetic and environmental effects on ovulation rate.

scholarly journals Placental Growth Factor Is Required for Ovulation, Luteinization, and Angiogenesis in Primate Ovulatory Follicles

Endocrinology ◽  
2017 ◽  
Vol 159 (2) ◽  
pp. 710-722 ◽  
Author(s):  
Hannah R Bender ◽  
Heidi A Trau ◽  
Diane M Duffy
Keyword(s):  
Growth Factor ◽  
Granulosa Cell ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Placental Growth Factor ◽  
Vascular Endothelial ◽  
Follicle Rupture ◽  
Ovulatory Follicles ◽  
Endothelial Growth Factor

Abstract Placental growth factor (PGF) is member of the vascular endothelial growth factor (VEGF) family of angiogenesis regulators. VEGFA is an established regulator of ovulation and formation of the corpus luteum. To determine whether PGF also mediates aspects of ovulation and luteinization, macaques received gonadotropins to stimulate multiple follicular development. Ovarian biopsies and whole ovaries were collected before (0 hours) and up to 36 hours after human chorionic gonadotropin (hCG) administration to span the ovulatory interval. PGF and VEGFA were expressed by both granulosa cells and theca cells. In follicular fluid, PGF and VEGFA levels were lowest before hCG. PGF levels remained low until 36 hours after hCG administration, when PGF increased sevenfold to reach peak levels. Follicular fluid VEGFA increased threefold to reach peak levels at 12 hours after hCG, then dropped to intermediate levels. To explore the roles of PGF and VEGFA in ovulation, luteinization, and follicular angiogenesis in vivo, antibodies were injected into the follicular fluid of naturally developed monkey follicles; ovariectomy was performed 48 hours after hCG, with ovulation expected about 40 hours after hCG. Intrafollicular injection of control immunoglobulin G resulted in no retained oocytes, follicle rupture, and structural luteinization, including granulosa cell hypertrophy and capillary formation in the granulosa cell layer. PGF antibody injection resulted in oocyte retention, abnormal rupture, and incomplete luteinization, with limited and disorganized angiogenesis. Injection of a VEGFA antibody resulted in oocyte retention and very limited follicle rupture or structural luteinization. These studies demonstrate that PGF, in addition to VEGFA, is required for ovulation, luteinization, and follicular angiogenesis in primates.

Effect of active immunization of heifers against inhibin on plasma FSH concentrations, ovarian follicular development and ovulation rate

1992 ◽  
Vol 134 (1) ◽  
pp. 11-18 ◽  
Author(s):  
R. G. Glencross ◽  
E. C. L. Bleach ◽  
B. J. McLeod ◽  
A. J. Beard ◽  
P. G. Knight
Keyword(s):  
Synthetic Peptide ◽  
Ovarian Function ◽  
Statistical Significance ◽  
Follicular Development ◽  
Ovarian Response ◽  
Active Immunization ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Α Subunit ◽  
Ovarian Follicular Development

ABSTRACT To study the effects of immunoneutralization of endogenous inhibin on gonadotrophin secretion and ovarian function, prepubertal heifers (n = 6) were actively immunized against a synthetic peptide replica of the N-terminal sequence of bovine inhibin α subunit bIα(1–29)Tyr30) coupled to ovalbumin. In contrast to ovalbumin-immunized controls (n=6), bIα(1–29)Tyr30-immunized heifers had detectable inhibin antibody titres (% binding to 125I-labelled bovine inhibin at 1:2000 dilution of plasma) of 17 ± 3% (s.e.m.) at puberty, rising to 31 ± 5% by the end of the study period 7 months later. Neither age (immunized: 295 ± 8 days; controls: 300 ± 5 days) nor body weight (immunized: 254 ± 13 kg; controls 251 ± 9 kg) at onset of puberty differed between groups. Although the difference did not reach statistical significance, mean plasma FSH concentrations recorded in inhibin-immunized heifers remained 35–40% higher than in controls throughout the 12-week period leading up to puberty (P = 0·14) and during nine successive oestrous cycles studied after puberty (P=0·10). Plasma LH concentrations did not differ between groups at any time during the study. Inhibin immunization had no effect on oestrous cycle length (immunized: 19·8±0·5 days; controls: 19·9±0·5 days). However, in comparison with controls, inhibinimmunized heifers had more medium sized (≥0·5 to <1 cm diameter) follicles during both the preovulatory (95%, P<0·001) and post-ovulatory (110%, P < 0·05 waves of follicular growth and more large (>1 cm diameter) follicles during the preovulatory wave (49%, P<0·05). In addition, the number of corpora lutea observed during the post-ovulatory phase of each cycle was significantly greater in the inhibin-immunized group (43%, P<0·01), as was the recorded incidence of cycles with multiple ovulations (19/56 in the inhibin-immunized group compared with 0/54 in controls; P<0·001). All six inhibinimmunized heifers had at least one cycle with multiple ovulation whereas none of the control heifers did so. These results support the conclusion that immunoneutralization of endogenous inhibin using a synthetic peptide-based vaccine can enhance ovarian follicular development and ovulation rate in heifers. Whether this ovarian response is dependent upon the expected increase in secretion of FSH remains to be established. Journal of Endocrinology (1992) 134, 11–18

scholarly journals Effects of active immunization against growth differentiation factor 9 and/or bone morphogenetic protein 15 on ovarian function in cattle

Reproduction ◽  
2009 ◽  
Vol 138 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Jennifer L Juengel ◽  
Norma L Hudson ◽  
Martin Berg ◽  
Keith Hamel ◽  
Peter Smith ◽  
...  
Keyword(s):  
Bone Morphogenetic Protein ◽  
Ovarian Function ◽  
Follicular Development ◽  
Active Immunization ◽  
Ovulation Rate ◽  
Differentiation Factor ◽  
Morphogenetic Protein ◽  
Growth Differentiation Factor 9 ◽  
Bone Morphogenetic Protein 15 ◽  
Ovarian Follicular Development

Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are essential for ovarian follicular growth in sheep, whereas only GDF9 is essential in mice suggesting that the roles of these oocyte-derived growth factors differ among species. At present, however, there is only limited information on the action of BMP15 and GDF9 in other species. Thus, the aim of this experiment was to determine the effect of neutralizing GDF9 and/or BMP15in vivoon ovarian follicular development and ovulation rate in cattle through active immunization using the mature regions of the proteins or peptides from the N-terminal area of mature regions. Immunization with the BMP15 peptide, with or without GDF9 peptide, significantly altered (increased or decreased) ovulation rate. In some animals, there were no functional corpora lutea (CL), whereas in others up to four CL were observed. From morphometric examination of the ovaries, immunization with GDF9 and/or BMP15 reduced the level of ovarian follicular development as assessed by a reduced proportion of the ovarian section occupied by antral follicles. In addition, immunization against GDF9 and/or BMP15 peptides reduced follicular size to <25% of that in the controls. In conclusion, immunization against GDF9 and BMP15, alone or together, altered follicular development and ovulation rate in cattle. Thus, as has been observed in sheep, both GDF9 and BMP15 appear to be key regulators of normal follicular development and ovulation rate in cattle.

scholarly journals The conflict between hierarchical ovarian follicular development and superovulation treatment

Reproduction ◽  
2010 ◽  
Vol 140 (2) ◽  
pp. 287-294 ◽  
Author(s):  
Kenneth P McNatty ◽  
Derek A Heath ◽  
Norma L Hudson ◽  
Karen L Reader ◽  
Laurel Quirke ◽  
...  
Keyword(s):  
Granulosa Cell ◽  
Granulosa Cells ◽  
Follicular Development ◽  
Follicular Phase ◽  
Ovulation Rate ◽  
Cell Populations ◽  
Antral Follicles ◽  
Functional States ◽  
Ovarian Follicular Development

In mammals with a low ovulation rate phenotype, ovarian follicular development is thought to be hierarchical with few, if any, antral follicles at similar stages of development. The hypothesis being tested herein was that if most follicles are in a functionally different state, then the application of exogenous hormones to increase ovulation rate will not overcome the hierarchical nature of follicular development. Using sheep as the experimental model, the functional states of all non-atretic antral follicles ≥2 mm diameter were assessed in individual ewes (N=10/group) during anoestrus with or without pregnant mare's serum gonadotrophin (PMSG) treatment, or after a standard superovulation regimen, or during the follicular phase of the oestrous cycle. The functional states of these follicles were assessed by measuring the FSH- or human chorionic gonadotrophin (hCG)-induced cAMP responses of granulosa cellsin vitro. There were significant overall effects across the treatment groups on the responses of granulosa cells to either FSH or LH (bothP<0.001). It was concluded that for anoestrous ewes with or without PMSG treatment, and ewes during the follicular phase, granulosa cell populations of many follicles (≥2 mm diameter) did not share a similar cAMP response to FSH (∼50% of follicles) or hCG (>90% of follicles) either on a per cell or total cell basis. After superovulation, ≤30 and 10% respectively of the granulosa cell populations shared similar responses to FSH and LH with regard to follicular diameter and cAMP output. Thus, exogenous hormone treatments used routinely for increasing oocyte yield do not effectively override the hierarchical pattern of ovarian follicular development during the follicular phase.

scholarly journals Aspects of Ovarian Function in a Line of Sheep with a Novel X-Linked Maternally-Imprinted Gene that is Associated with an Increased Ovulation Rate

2021 ◽  
Author(s):  
◽  
Elisabeth Sheinach Feary
Keyword(s):  
Gene Expression ◽  
Pituitary Gland ◽  
Ovarian Function ◽  
Follicular Development ◽  
Cell Types ◽  
Ovulation Rate ◽  
Chromosome 2 ◽  
Ovarian Follicular Development ◽  
Er Alpha ◽  
Large Ovary

<p>Fecundity is a term that refers to the number of offspring produced per female. It combines fertility (i.e. ability to produce offspring) and prolificacy (i.e. number of offspring). Ovulation rate i.e. the number of mature eggs released from the ovaries during one reproductive cycle in sheep, as with other mammals, is controlled by an exchange of hormonal signals between the pituitary gland and the ovary. Genetic mutations affecting ovulation are commonly referred to as the fecundity genes (Fec). The most obvious outcome is the number of offspring produced. There is already evidence of a number of major genes affecting the ovulation rate in sheep, specifically the Booroola, Inverdale, Hanna and more recently the Woodlands gene. The sheep carrying the Woodlands gene arose because the mutation was first recognised on a farm in Woodlands, Southland, New Zealand. Woodlands have a novel, X-linked maternally-imprinted, fecundity trait referred to as FecX2w, where Fec = fecundity, X = X chromosome, 2= 2nd mutation identified on X and W= Woodlands. The studies in this thesis investigated ovarian follicular development in both 4-week old Woodland carrier (W+) and non-carrier (++) lambs and adult ewes and evaluated some aspects of the endocrine interactions between the ovary and pituitary gland. The purpose was to identify potential physiological effects of the FecX2w gene on ovarian function. A confounding issue during these studies was the discovery that a large ovary phenotype (LOP) which was present in many of the W+ but not ++ lambs at 4 weeks of age was in fact a coincidence and not linked to the FecX2w mutation. The key findings from the studies of lambs and/or ewes that were carriers (W+) or non-carriers (++) of the FecX2w gene were: 1. No genotype differences were present either in the numbers of primordial (i.e. Type 1/1a follicles) or developing preantral (i.e. Types 2-4 follicles); 2. Significant genotype differences were present in the numbers of small antral (Type 5) follicles (W+>++; p<0.05); 3. An earlier onset of antral follicular development in W+ vs. ++ ewes with irregularities in morphology between the basement membrane and stroma in the former; 4. No genotype differences in the onset of gene expression during follicular development or in the cell-types expressing GDF9, BMP15, alpha inhibin, beta A inhibin and beta B inhibin, FSHR, ER alpha, or ER beta; 5. No genotype differences in the levels of GDF9 or BMP15 gene expression in oocytes throughout follicular growth; 6. No genotype difference in the diameters that follicles reached in W+ vs. ++ ewes; 7. Some lambs at 4-weeks of age had unusually large ovaries with an exceptional level of antral follicular development that is reminiscent of a polycystic ovarian condition. The underlying cause of this condition is unknown. In conclusion, the physiological characteristics of ovarian follicular development in ewes with the FecX2w gene is different from that in ewes with the Booroola, Inverdale, Hanna or other recently identified mutations.</p>

Sign in / Sign up

Export Citation Format

Share Document