Effect of different types of cryoprotectants on developmental capacity of vitrified-thawed immature buffalo oocytes

The study aimed to determine the effects of different types of cryoprotectants on developmental capacity of vitrified-thawed immature buffalo oocytes. The vitrification solution [VS] consisted of Dulbecco's phosphate buffered saline [DPBS] supplemented with 0.5 M sucrose, 0.4% bovine serum albumin [BSA] and different types of molar [M] concentrations of the cryoprotectants which composed of either glycerol [G], ethylene glycol [EG] or dimesthyl sulfoxide [DMSO] in order to determine the best type of vitrification cryoprotectants. The concentrations tested were 4 M, 7 M and 7M concentration of G, EG and DMSO, respectively. Cumulus oocyte complexes [COCs] were obtained from slaughterhouse ovaries. Oocytes were vitrified immediately after collection .The COCs were pre-equilibrated in 50% of the VS for 3-5 min, then kept in VS for 1 min and loaded in pre-sterilized 0.25 ml straws for 7-10 days of storage in liquid nitrogen. The straws were thawed in warm water at 37°C for 10 seconds and COCs were evaluated for morphological damage. Morphologically normal COCs were cultured in vitro and evaluated for maturation. Oocytes were fertilized with frozen-thawed semen capacitated in Brackett and Oliphant [BO] medium contained heparin and caffeine and evaluated for cleavage and embryonic development. The results revealed that the proportion of buffalo oocytes found to be morphologically normal was significantly [p<0.05] higher in EG and DMSO than those obtained in G [85.0 and 83.33 vs 65.0%, respectively]. Among the damaged oocytes, cracking of zona pellucida was the most frequent abnormality observed. A significantly higher [p<0.05] percentage of maturation and cleavage rates derived from vitrified -thawed immature oocyte in EG and DMSO than those obtained in G [47.05, 46.67%; 28.57, 25.71 vs 30.76% and 10.0%, respectively]. A similar trend was observed in blastocyst stage produced in vitro. However, in vitro developmental competence was higher for vitrified-thawed fresh oocytes [control] than those obtained from all groups of cryoprotectants. that 7M solution of EG or DMSO could be used for vitrification of immature buffalo oocytes for their subsequent utilization in the in vitro maturation, fertilization and embryo production

Effect of ovarian morphology on in vitro oocyte recovery and quality, and certain follicular fluid steroids hormones concentrations in ewes

The present study was conducted to investigate the effects of ovarian morphology on oocyte quantity and quality, as well as on follicular fluid steroid hormones concentrations. Fifty pairs of ovaries were collected from Barbari ewes and grouped into right, left, CL bearing and non-CL bearing ovaries. The weight, length, width and thickness of the right, left, CL bearing and non-CL bearing ovaries were recorded. The follicles were classified according to their diameter into 3 groups; small [<2mm], medium [2-4mm] and large [>4mm] follicles. Oocytes were classified according to their morphology into 3 grades; COCS [Compact cumulus oocyte complexes], POCS [Partially invested with less than three layers of cumulus cells] and DO [denuded oocyte]. The concentrations of progesterone and estradiol 17 beta in the follicular fluid were estimated. Results indicated that, dimensions of both right and left ovaries were not significantly differed. However, the ovarian dimensions as well as their weights were significantly [P < 0.05] affected by the presence of CL, being higher in the CL bearing ovary. The average number of large follicles were significantly [P < 0.05] increased in the right ovary when compared to the left one. The recovered COCs number was found to be significantly higher [P < 0.05] in the right than left ovaries. A greater number of vesicular follicles and aspirated COCS were found in the non-CL bearing ovary than in the CL bearing ovary. The non CL bearing ovaries provide larger numbers as well as higher quality of COCs when compared to CL bearing ovaries and that the former can be used to collect good quality COCs for in vitro production of sheep embryos. The progesterone concentration of follicular fluid was significantly higher in CL- and non-CL bearing ovaries [27.75 and 12.33 ng/ml; P < 0.05, respectively]. Non-CL bearing ovaries had significantly [P < 0.05] higher concentration of estradiol 17beta than those found in CL bearing ovaries [22.10 vs.8.43 pg/ml, respectively]. It can be concluded that non-CL bearing ovaries provide a higher number as well as superior quality of COCs than those obtained from ovaries bearing CL suggesting that the ovaries without CL can be used to collect good quality of COCs in view of in vitro production of sheep embryos [IVP]

anatomical structures of sheep cervix and its influence on the transcervical passage of an inseminating catheter into the uterine lumen

A total of 103 Barbari sheep cervices were used to conduct this work. The cervices were allocated into two main series obtained from an abattoir during the breeding season. The first series was 43 of adult ewe cervices, while the second was a series of 60 cervices obtained from ewe lambs. The tract of both series was further subdivided into luteal and follicular phases based on ovarian structure. The morphology of the cervical external os was classified as slit, papilla, duckbill, flap or rose. An inseminating pipette was inserted into the cervical lumen and the depth of penetration was recorded. The cervix was opened longitudinally, its length and number of cervical rings and its arrangement were recorded. Theresults revealed that there was a significant [P < 0.01] effect of age on the length of the cervix. Similarly, the length of cervix was significantly [P < 0.001] related to the number of cervical rings but not to the stage of the oestrous cycle. The maximum depth of cervical penetration of an inseminating catheter was affected by cervical grade and the stage of the oestrous cycle. The distribution of os types differed with age, with rose types were more common in adult ewes, and papilla os types were more common in ewe lambs. In conclusion, the success of transcervical artificial insemination [TCAI] in ewes is highly dependent on the anatomy of the cervical lumen and the stage of the oestrous cycle

Chromosome configuration during in vitro maturation of dromedary camel oocytes

The aim of the present study was to examine the changes in the chromosomal configuration of camel oocyte during in vitro maturation [IVM] at different culture periods of 24, 30, 36 and 48 hours and to compare the influence of pregnant camel serum and fetal calf serum on IVM of camel oocytes at 24-30 hours. A total of 1978 oocytes was collected from 390 ovaries of slaughtered camels by aspiration method. The average number of camel oocytes per ovary was 5.30 +/- 0.22. The proportion of COC, POC and DO oocytes was 29.27%, 32.90% and 32.61%, respectively. In addition, 5.21% of oocytes were degenerated. A high percentage of maturation was obtained at 24-30 hours [47.70% and 48.35%, respectively]. At 48 hours post-maturation, all metaphases were undefined due to the degeneration of chromatin. It was found that the addition of pregnant camel serum had no beneficial effect on IVM of camel oocytes in comparison with the fetal calf serum [40.10% vs. 45.34%, respectively]