Human oocyte cytometry and fertilisation rate after subzonal insemination

Zygote ◽  
1995 ◽  
Vol 3 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Jean Philippe Wolf ◽  
Sylvie Bulwa ◽  
Daniel Rodrigues ◽  
Pierre Jouannet
Keyword(s):  
Zona Pellucida ◽  
Human Oocyte ◽  
Oocyte Diameter ◽  
Antisperm Antibodies ◽  
Subzonal Insemination ◽  
Fertilisation Rate ◽  
Defect Groups ◽  
The Mean ◽  
Dynein Arms

SummaryThe cytometry of 545 oocytes was evaluated during subzonal insemination (SUZI; 85 attempts), on day 0 (egg retrieval and SUZI), day 1 and day 2(embryo transfer). On day 0, the egg and oolemma diameters (mean ± SD) were 164.0 ± 19.6 μm and 114.2±16.8 μ5m respectively.The zona thickness was 17.8± 13.4 μm and correlated with the oolemma diameter(r = 0.24, p < 0.001). The fertilisation rate was significantly lower for the smaller oocytes (less than 108 μm diameter) compared with the larger oocytes (over 108μm) (9.8% vs 21.2% respectively; p < 0.05). These was little variation in oocyte diameter according to nuclear status. However, oocyte diameter increased significantly between day 0 and day 1 (p < 0.001) for both fertilised and unfertilised oocytes. Six different indications for SUZI were investigated in detail: three with non-specific (normal and subnormal sperm with in vitro fertilization failure, oligoasthenospermia) and three with specific sperm defects (flagellar dyskinesia, absence of outer dynein arms, antisperm antibodies). Oocytes from the non-specific defect groups had significantly smaller diameters than the others (p < 0.05). The mean fertilisation rate was related to the mean oolemma diameter for the groups with non-specific sperm defects and the group lacking dynein arms (LODA) (r = 0.91, p < 0.05). Eggs from the groups of patients with LODA and those with antisperm antibodies had thicker zona pellucida than others (p < 0.05). These findings suggest that in addition to nuclear criteria of maturity, the growth of oocytes is an important factor for fertilising ability. Insufficient development of the ooplasm may contribute to fertilisation failure, particularly when sperm with functional defects are used. In contrast, a thick zona pellucida may prevent sperm with specific anomalies such as LODA or antisperm antibodies from penetrating into the perivitelline space.

227 CALRETICULIN, A 60-kDa PROTEIN, PREVENTS POLYSPERMY IN ZONA PELLUCIDA-FREE PIG OCYTES

2013 ◽  
Vol 25 (1) ◽  
pp. 261
Author(s):  
R. Romar ◽  
C. Soriano-Úbeda ◽  
M. D. Saavedra ◽  
J. Gadea ◽  
M. Avilés ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Calcium Binding ◽  
Statistical Significance ◽  
P Value ◽  
Oocyte Activation ◽  
Cortical Granules ◽  
Chaperone Protein ◽  
The Mean

After gamete membrane fusion or artificial oocyte activation, cortical granules undergo exocytosis and the released content modifies the zona pellucida (ZP), preventing polyspermy. Calreticulin (CRT), a calcium-binding highly conserved protein of 60 kDa, is contained in cortical granules from hamster eggs (Muñoz-Gotera et al. 2001 Mol. Reprod. Dev. 60), and we recently showed it is exocytosed from chemically activated ZP-free pig oocytes (Romar et al. 2012 Reprod. Fertil. Dev. 24). When pig ZP-enclosed oocytes were incubated with CRT, monospermy was not improved (Romar et al. 2011, Maternal communication with gametes and embryo, p. 72), suggesting that the likely role of CRT in preventing polyspermy might be carried out at the oolemma level. Our objective was to evaluate whether CRT prevents polyspermy in pig ZP-free oocytes by treating the cells with this protein before being inseminated. In vitro-matured cumulus–oocyte complexes (44 h, NCSU-37 medium) were decumulated and ZP was digested with Tyrode’s acid. The ZP-free oocytes were incubated for 30 min in TALP medium supplemented with 0, 100, 1000, and 5000 pg of CRT (ab91577, Abcam, Cambridge, MA, USA) per oocyte. After washing, ZP-free oocytes were inseminated (25 000 sperm mL–1) and gametes were co-cultured for 18 h. Putative zygotes were fixed and stained with Hoechst 33342 to analyse the fertilization results. Four replicates with 30 to 35 oocytes per group were done, and results were analysed by one-way ANOVA. A P-value ≤0.05 was taken to denote statistical significance. Incubation with CRT did not affect penetration rates that were similar among groups (77.12 ± 3.88 and 72.73 ± 4.07, respectively, for the 0- and 5000-pg CRT groups). However, the mean number of sperm per penetrated oocyte decreased from 3.01 ± 0.28 (0-pg group) to 2.07 ± 0.16 (5000-pg group), and monospermy rate increased from 30.77 ± 4.87 (0-pg group) to 52.27 ± 5.36 (5000-pg group; P ≤ 0.05). Incubation with CRT did not affect the number of sperm attached to oolemma, which was similar among all groups (11.45 ± 1.16 v. 10.75 ± 1.17, respectively, for 0 and 5000 pg of CRT). These preliminary data suggest that CRT, a protein exocytosed after oocyte activation, participates in the membrane block to polyspermy in pigs. Future studies to describe the exact mechanism of action of this chaperone protein are necessary. Supported by MEC and FEDER (AGL2009-12512-C02-01).

A stereological study on organelle distribution in human oocytes at prophase I

Zygote ◽  
2015 ◽  
Vol 24 (3) ◽  
pp. 346-354 ◽  
Author(s):  
Ana Sílvia Pires-Luís ◽  
Eduardo Rocha ◽  
Carla Bartosch ◽  
Elsa Oliveira ◽  
Joaquina Silva ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Smooth Endoplasmic Reticulum ◽  
Molecular Data ◽  
Human Oocyte ◽  
Human Oocytes ◽  
Prophase I ◽  
Organelle Distribution ◽  
Transmission Electron ◽  
Maturation Stages

SummaryThe ultrastructural analysis of human oocytes at different maturation stages has only been descriptive. The aim of this study was to use a stereological approach to quantify the distribution of organelles in oocytes at prophase I (GV). Seven immature GV oocytes were processed for transmission electron microscopy and a classical manual stereological technique based on point-counting with an adequate stereological grid was used. The Kruskal–Wallis test and Mann–Whitney U-test with Bonferroni correction were used to compare the means of the relative volumes occupied by organelles in oocyte regions: cortex (C), subcortex (SC) and inner cytoplasm (IC). Here we first describe in GV oocytes very large vesicles of the smooth endoplasmic reticulum (SER), vesicles containing zona pellucida-like materials and coated vesicles. The most abundant organelles were the very large vesicles of the SER (6.9%), mitochondria (6.3%) and other SER vesicles (6.1%). Significant differences in organelle distribution were observed between ooplasm regions: cortical vesicles (C: 1.3% versus SC: 0.1%, IC: 0.1%, P = 0.001) and medium-sized vesicles containing zona pellucida-like materials (C: 0.2% versus SC: 0.02%, IC: 0%, P = 0.004) were mostly observed at the oocyte cortex, whereas mitochondria (C: 3.6% versus SC: 6.0%, IC: 7.2%, P = 0.005) were preferentially located in the subcortex and inner cytoplasm, and SER very large vesicles (IC: 10.1% versus C: 0.9%, SC: 1.67%, P = 0.001) in the oocyte inner cytoplasm. Further quantitative studies are needed in immature metaphase-I and mature metaphase-II oocytes, as well as analysis of correlations between ultrastructural and molecular data, to better understand human oocyte in vitro maturation.

In Vitro maturation rate of oocytes collected from indigenous cows of Assam after slaughter

2015 ◽  
Vol 49 (6) ◽  
Author(s):  
S. S. Deka ◽  
D. J. Kalita ◽  
S. Sarma ◽  
D. J. Dutta
Keyword(s):  
Zona Pellucida ◽  
Maximum Yield ◽  
Cumulus Cells ◽  
Cumulus Expansion ◽  
Slaughter House ◽  
Oocyte Collection ◽  
Maturation Rate ◽  
The Mean ◽  
Ideal Method

Sixty healthy ovaries were collected from local slaughter house. Oocytes from small and medium sized follicles (2-8 mm in diameter) were selected for oocyte collection using aspiration followed by slicing . A and B category ( cumulus oocyte complexes (COCs) with more than 5 layers and 3-5 layers respectively of compact cumulus cells surrounding the zona pellucida) were selected for <italic>in vitro</italic> maturation. A total of 361 oocytes were found to be matured with overall mean maturation rate of 82.59 ± 0.02%. The mean number of grade A, B and C oocytes recovered per ovary was 4.26 ± 0.53, 3.05 ± 0.31 and 1.25 ± 0.19, respectively. The overall recovery of grade A, B and C oocytes were 256, 183 and 74 . Out of 439 oocytes 58.86 ± 0.05%, 33.23 ±0.04 % and 9.90 ± 0.04 % showed +++, ++ and + degrees of cumulus expansion, respectively. It was concluded that aspiration followed by slicing is an ideal method for maximum yield of oocytes and <italic>in vitro</italic> maturation in indigenous cow of Assam.

scholarly journals Fertilization and Development of Conjoined Human Oocyte from a Binovular Follicle Containing Two Individual Oocytes Surrounded by a Zona Pellucida

2021 ◽  
Author(s):  
Guangzhong Jiao ◽  
Jianhua Wang ◽  
Lili Chen ◽  
Yinghua Shan ◽  
Hua Xing ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Clinical Characteristics ◽  
Fertilization Rate ◽  
Human Oocyte ◽  
Laboratory Setting ◽  
High Quality ◽  
Significant Difference ◽  
Maturation Rate ◽  
The Mean ◽  
Definition Of

Abstract The most reliable definition of conjoined oocytes is the inclusion of two oocytes within a common zona pellucida(ZP) or their fusion in the zonal region. Because the available data are extremely limited, the significance of conjoined oocytes in IVF laboratory setting has been questionable. We analyzed the characteristics of 18 patients with conjoined oocytes in our center. The maturation of conjoined oocytes were asynchronous. Most of the cases were that one oocyte in each pair of conjoined oocytes was in the MII stage and the other was in the GV stage. The maturation rate and fertilization rate of conjoined oocytes were significantly lower than that of normal oocytes. There was no significant difference in the rate of cleavage and D3 High-quality embryo, but the rate of blastocyst formation of conjoined oocytes decreased significantly. The area of larger oocytes in conjoined oocytes was not different from that of normal oocytes, and its companion was significantly smaller than that of normal oocytes. The mean ZP thickness of all oocytes, larger or smaller, was significantly thinner than that of normal oocytes. After analyzing the clinical characteristics of the patients, it was suggested that the higher estrogen level or the more number of maturation follicles on HCG day were more likely to promote the emergence of conjoined oocytes.

Meiotic competence of in vitro grown goat oocytes

Reproduction ◽  
2000 ◽  
pp. 367-373 ◽  
Author(s):  
N Crozet ◽  
M Dahirel ◽  
L Gall
Keyword(s):  
Germinal Vesicle ◽  
Oocyte Diameter ◽  
Germinal Vesicle Breakdown ◽  
Cell Monolayers ◽  
Group A ◽  
The Mean ◽  
Group B ◽  
P34 Cdc2 ◽  
Meiotic Competence

The objective of the present study was to grow meiotically incompetent goat oocytes from early antral follicles in vitro and to render them competent to undergo germinal vesicle breakdown. Cumulus-oocyte complexes with pieces of parietal granulosa cells were isolated from follicles 0.35-0.45 mm in diameter using both mechanical and enzymatic methods. The cumulus-oocyte complexes were divided into two groups according to oocyte diameter (group A: < 95 microm; group B: > 95 microm) and cultured for 8 or 9 days on granulosa cell monolayers. Within 8 days of culture, the mean oocyte diameter increased from 86 +/- 0.4 microm to 95 +/- 0.7 microm in group Aand from 106 +/- 0.2 microm to 109 +/- 0.5 microm in group B. After 9 days of culture, the mean diameter of oocytes from groups A and B were 99 +/- 0.5 microm and 112 +/- 0.4 microm, respectively. The meiotic competence of oocytes grown in vitro was evaluated by in vitro maturation. Within 8 days of culture, only 3% of oocytes from group A and 6% of oocytes from group B acquired the ability to undergo germinal vesicle breakdown. After 9 days of culture, 7% of group A oocytes and 42% of group B oocytes were competent to resume meiosis. The expression of p34(cdc2) in oocytes grown in vitro was analysed by the western blot technique. During 9 days of culture, p34(cdc2) accumulated in both groups of growing oocytes, but its concentration was lower than in fully grown oocytes used as controls. The results showed for the first time that goat oocytes from early antral follicles can grow, accumulate p34(cdc2) and acquire the ability to resume meiosis, when cultured for 9 days on granulosa cell monolayers.

204 AMINO-REACTIVE CROSSLINKER BIS(SULFOSUCCINIMIDYL)SUBERATE INDUCES ZONA PELLUCIDA HARDENING AND REDUCES PENETRATION IN PIG IN VITRO FERTILIZATION

2008 ◽  
Vol 20 (1) ◽  
pp. 181
Author(s):  
L. Grullón ◽  
S. Cánovas ◽  
C. Matás ◽  
R. Romar ◽  
P. Coy
Keyword(s):  
Zona Pellucida ◽  
Control Group ◽  
Digestion Time ◽  
Vitro Fertilization ◽  
Amide Bonds ◽  
High Penetration ◽  
The Mean ◽  
Pronuclear Formation ◽  
Dose Dependent Increase

Zona pellucida (ZP) hardening is considered to be the final step in the prevention of polyspermy during fertilization in mammals. However, unfertilized pig oviductal oocytes show a resistance of hours or days to pronase digestion (Broermann et al. 1989 J. Anim. Sci. 67, 1324–1329). We previously demonstrated that the amino-reactive crosslinker DSP is effective in inducing ZP hardening and improves the monospermy levels at pig IVF (Coy et al. 2007, Reprod. Dom. Anim., in press). In this study, a different chemical crosslinker, BS3 [bis(sulfosuccinimidyl) suberate], which also forms stable amide bonds among proteins, was used to evaluate its effect on ZP digestion time, penetration, male pronuclear formation and monospermy percentages, and the mean number of sperm per oocyte. In experiment 1, porcine in vitro-matured oocytes (n = 300) were incubated for 30 min at 0, 0.06, 0.30, or 0.60 mg mL–1 of BS3 in TALP medium and assessed for ZP digestion time in 0.5% pronase solution. The results (analyzed by ANOVA in all the experiments) showed a significant (P ≤ 0.01) dose-dependent increase in ZP hardening, from 69.0 s in the control to 426.3, 2028.3, and 2979.2 s, respectively, for the different BS3 concentrations. In experiment 2, oocytes (n = 473) were fertilized in vitro after no treatment or treatment with BS3 at 0.06, 0.30, and 0.60 mg mL–1. Fresh ejaculated spermatozoa were selected by Percoll� gradient 45:90. Oocytes were inseminated with 105 sperm mL–1, which resulted in high penetration and polyspermy percentages in the control group (83.1 and 89.9%, respectively). However, for the BS3-treated oocytes, significant differences compared with the control group (P ≤ 0.001) were observed in all 3 groups, showing penetration percentages of 22.2, 18.1, and 21.5%, respectively, and monospermy percentages of 100, 88.2, and 95.0%, respectively. The mean numbers of sperm per oocyte were 1.0, 1.1, and 1.05 for the BS3 groups, which were significantly different from 5.0 for the control group. In conclusion, BS3 can be used to induce ZP hardening in the pig and regulate polyspermy in IVF systems, although additional experiments are necessary to find the optimal concentration to improve the penetration percentages with high levels of monospermy. Granted by MEC and FEDER (AGL2006-03495).

198 FUNCTIONAL EVIDENCE FOR THE EXISTENCE OF AN OVIDUCTAL FACTOR THAT INDUCES ZONA PELLUCIDA HARDENING AND REGULATES POLYSPERMY IN THE PIG AND COW

2008 ◽  
Vol 20 (1) ◽  
pp. 178 ◽  
Author(s):  
S. Cánovas ◽  
L. Grullón ◽  
R. Romar ◽  
C. Matás ◽  
M. Avilés ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Zona Pellucida ◽  
Control Groups ◽  
Digestion Time ◽  
Vitro Fertilization ◽  
The Mean ◽  
Oviductal Fluid ◽  
Bovine Oocytes

Many differences between in vivo and in vitro fertilization (IVF) efficiency in mammals are related to the differences between IVF media and oviductal fluid. One of the best known examples is the frequency of polyspermy observed under in vitro conditions in cattle (Roh S et al. 2002 J. Vet. Med. Sci. 64, 667–671) and, in particular, in pigs (Coy P and Romar R 2002 Reprod. Fertil. Dev. 14, 275–286). Zona pellucida (ZP) resistance to pronase digestion (ZP hardening) has been considered as a postfertilization event contributing to the block of polyspermy in mammals (Green D 1997 Rev. Reprod. 2, 147–156). However, pig and cow unfertilized ovulated oocytes show a ZP hardening of hours or days (Katska L et al. 1999 Reprod. Dom. Anim. 34, 255–259; Kolbe T and Holtz W 2005 Theriogenology 63, 1695–1705) compared with the minutes or seconds observed in the in vitro-matured oocytes, even after fertilization (Coy P et al. 2002 Reproduction 124, 279–288; Coy P et al. 2005 Reproduction 129, 19–26). Consequently, we propose the existence of an oviductal factor that induces ZP hardening before any contact of the oocyte with the sperm, thus regulating polyspermy. Porcine and bovine oviductal fluid was obtained by aspiration of oviducts collected at the slaughterhouse and stored frozen. In vitro-matured porcine and bovine oocytes were incubated for 30 min in the oviductal fluid, washed thoroughly in fresh medium, and either assessed for ZP digestion time or in vitro fertilized. The results, analyzed by ANOVA, showed a very strong ZP hardening in oviductal-treated oocytes (2866.83 � 94.4 s in the pig and 4301.1 � 441.7 s in the cow) compared with control oocytes (63.5 � 2.9 s in the pig and 124.2 � 5.9 s in the cow). Moreover, the percentage of monospermy for the oviductal-treated oocytes was significantly higher in both species (50.0 � 10.0% in the pig and 91.7 � 3.0% in the cow) compared with the control groups (5.56 � 3.8% in the pig and 80.8 � 3.5% in the cow). Percentage penetration did not change in porcine oocytes but decreased in bovine oocytes (58.1 � 3.3 v. 38.4 � 3.3, P ≤ 0.001), whereas the mean number of sperm per oocyte decreased for the porcine-treated oocytes (2.7 � 0.2 v. 8.2 � 0.4, P ≤ 0.001) and did not change for the bovine oocytes. These results support the hypothesis that an oviductal factor induces ZP hardening, contributing to the control of polyspermy in the pig and cow, and that it could be used to improve the output of IVF. Supported by MEC and FEDER (AGL2006-03495).

Zona pellucida solubility and cortical granule complements in human oocytes following assisted reproductive techniques

Zygote ◽  
2001 ◽  
Vol 9 (3) ◽  
pp. 201-210 ◽  
Author(s):  
C. Manna ◽  
L. Rienzi ◽  
E. Greco ◽  
M. Sbracia ◽  
A. Rahman ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Germinal Vesicle ◽  
Inverse Correlation ◽  
Class I ◽  
Dissolution Time ◽  
Cortical Granule ◽  
Human Oocytes ◽  
Fertilisation Rate ◽  
Reproductive Techniques

In this study the solubility to α-chymotrypsin of the zona pellucida (ZP) of human oocytes and polyploid embryos obtained during various clinical procedures of assisted fertilisation (IVF, ICSI, cyropreservation) was evaluated. The aim of the study was to determine whether changes in ZP solubility occur during such procedures and whether abnormal solubility could be likened to fertilisation failure. Correlation between ZP solubility and cortical granule (CG) density was also studied. The results showed that ZP solubility varied considerably among germinal vesicle or metaphase oocytes obtained from different subjects, but was essentially identical for the oocyte cohort obtained from individual women. On the basis of ZP solubility metaphase oocytes were subdivided into two classes: class I, average ZP dissolution time ± SE = 24.1 ± 0.9 min, n = 28; and class II, 46.7 ± 2.0 min, n = 13. Prolonged ZP dissolution times of metaphase oocytes were significantly correlated with a low in vitro fertilisation rate in sibling oocytes. The zonae of fertilised eggs (polyploid embryos) showed long solubilisation times (IVF: 45.3 ± 3.4 min, n = 18; ICSI: 48.9 ± 2.7 min, n = 19). ZP solubility of oocytes that failed to fertilise was intermediate between that of class I metaphase oocytes and embryos (unfertilised IVF: 33.0 ± 2.7 min, n = 13; unfertilised ICSI: 43.0 ± 2.4 min, n = 9). A moderate spontaneous ZP hardening occurred when metaphase oocytes were cultured for 24 h. Finally, cryopreservation of unfertilised oocytes caused hardening of their ZP, with dissolution times that were comparable to those found in fertilised eggs (49.5 ± 2.3 min, n = 10). In most cases, an inverse correlation was found between ZP dissolution time and CG density (longer solubilisation times corresponding to lower CG density). ZP hardening caused by cryopreservation, however, was not associated with a significant reduction in CG density in most of the oocytes examined.

The importance of trace minerals copper, manganese, selenium and zinc in bovine sperm–zona pellucida binding

Zygote ◽  
2019 ◽  
Vol 27 (02) ◽  
pp. 89-96 ◽  
Author(s):  
Juan Patricio Anchordoquy ◽  
Juan Mateo Anchordoquy ◽  
Raúl Martín Lizarraga ◽  
Noelia Nikoloff ◽  
Ana Malen Pascua ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Membrane Integrity ◽  
Trace Minerals ◽  
Bovine Sperm ◽  
Copper Manganese ◽  
Total Antioxidant ◽  
Functional Membrane ◽  
Bovine Spermatozoa ◽  
The Mean

SummarySperm–zona pellucida (ZP) binding is a necessary event for successful fertilization. The aim of this study was to determine the effect of trace minerals such as copper (Cu), manganese (Mn), selenium (Se) and zinc (Zn) on bovine spermatozoa binding to ZP. Sperm viability, functional membrane integrity, acrosomal status (AS), total antioxidant capacity (TAC) and sperm lipid peroxidation (LPO) were also evaluated. For the present study, in vitro fertilization (IVF) medium was supplemented with Cu (0.4 µg/ml Cu), Mn (5 ng/ml Mn), Se (100 ng/ml Se), Zn (0.8 µg/ml Zn), all minerals (Cu+Mn+Se+Zn), or tested without supplement (Control). Considerably more sperm bound to ZP when Cu, Se or Zn were added to the IVF medium, but there were no difference compared with the Control, Mn and Cu+Mn+Se+Zn groups. After 1 h of incubation, viability was increased by the addition of Cu, Mn and Se with respect to the Control but, after 2 h, viability was higher only with the addition of Mn to IVF medium. Functional membrane integrity improved in sperm treated with Cu. Acrosome integrity was higher in sperm treated with Zn after 1 h of incubation. LPO was significantly higher in sperm treated with Cu or Cu+Mn+Se+Zn. The mean TACs of sperm treated with Cu, Mn, Zn or Cu+Mn+Se+Zn were lower than in the Control. In conclusion, the results obtained in the present study determined that the presence of Cu, Se and Zn in the IVF medium increased the number of spermatozoa bound to the ZP, highlighting the importance of these minerals in the fertilization process.

Follicle size and oocyte diameter in relation to developmental competence of buffalo oocytes in vitro

2002 ◽  
Vol 14 (1) ◽  
pp. 55 ◽  
Author(s):  
H. M. Raghu ◽  
S. Nandi ◽  
S. M. Reddy
Keyword(s):  
In Vitro Maturation ◽  
Developmental Competence ◽  
Oocyte Diameter ◽  
Embryo Yield ◽  
Mean Diameter ◽  
Follicular Size ◽  
Follicle Size ◽  
The Mean ◽  
Size Oocyte

Follicular size, oocyte morphology and diameter were investigated for their possible relationship with in vitro developmental competence of buffalo oocytes. Cumulus oocytes complexes (COCs), aspirated from small (<3 mm), medium (3–8 mm) and large (>8 mm) follicles of normal ovaries and cystic ovarian follicles of abattoir-derived ovaries, were graded for their morphological appearance and were cultured to assess their developmental competence. The influence of cystic follicles on maturational competence of COCs recovered from co-existing follicles of cystic ovaries was studied. The mean diameter of oocytes from follicles of different size were examined, and the influence of oocyte diameter—(i) <126 m; (ii) 127–144 m; (ii) 145–162 m; and (iv) >163 m—on in vitro maturation, cleavage and embryo yield was studied. Results suggested that increased fertilization, cleavage and embryo development were significantly (P<0.05) higher in COCs aspirated from large follicles, followed by medium and small-sized normal follicles, and the presence of cystic follicles had no significant (P<0.05) effect on the maturation competence of the COCs recovered from co-existing follicles. The mean diameter of the buffalo oocyte obtained from normal ovaries was found to be 146.4 m and the rate of blastocyst production in vitro was significantly higher (P<0.05) in oocytes with diameters greater than 145 m. In conclusion, the larger the size of the follicles and oocytes, the greater the developmental competence in vitro of buffalo oocytes.

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