الفهرس 
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Abstract
The present study was designed (i) to evaluate the effect of seasonal variations and the presence of corpus luteum on the yield and quality of recovered follicular oocytes of camel ovaries.; (ii) to investigate the effect of addition of gonadotropin hormones (PMSG + hCG) to culture media (TCM-199, Ham’s F-10 or RPMI-1640) supplemented with camel serum on meiotic maturation of camel oocytes in vitro under different culture periods (28, 32 or 42 hours).; (iii) as well as to study the effect of oocyte quality of camel oocytes on meiotic maturation of in vitro. In order to achieve that, the following steps were done:
• Camel ovaries were collected during breeding and non-breeding seasons from a local slaughterhouse and transported to the laboratory in saline containing antibiotics. On arrival to the laboratory, ovaries were divided into those from pregnant donors (having a corpus luteum) and ovaries from non- pregnant donors (without a corpus luteum).
• Camel oocytes were recovered from visible antral follicles
(3-10 mm in diameter) by aspiration technique.
• Oocytes were divided into two types including cumulus–oocyte complexes (COCs) and denuded oocytes (DOs).
• COCs oocytes were classified according to their cumulus cells into three classes; excellent, good and poor.
• The COCs and DOs oocytes were matured separately in culture media (TCM-199, Ham’s F-10 or RPMI-1640) supplemented with camel serum and gonadotropin hormones (PMSG + hCG) for different three times (28, 32 and 42 hr.) at 39°C under 5% CO2 pressure and 95% humidity.
• At the end of each culture period, the COCs and DOs oocytes were recovered, fixed and stained with 1% aceto-orcein and examined for cytogenetic characteristics (nuclear morphology) with a phase contrast microscope.
• Meiotic maturation rate was evaluated as the percentage of oocytes reaching metaphase-II (M II) stage.
• The obtained data were statistically analyzed using analysis of variance (ANOVA) and least significant difference test (LSD).
The results obtained from this work could be summarized as follows:
1- The present results cleared that the average number of recovered oocytes per ovary was significantly elevated during winter and spring compared to those found during summer and autumn (6.71 and 5.57 Vs 2.95 and 4.26 respectively).
2- Also, significantly more proportions of high quality oocytes (COCs) were recovered during winter and spring than those harvested during summer and autumn (4.16, 3.04 Vs 1.18 and 2.17, respectively).
3- The total oocytes recovered per ovary and the proportion of COCs categories were more (P<0.05) in ovaries without corpus luteum (CL) than those collected from ovaries with CL (5.39 and 3.04 Vs 4.36 and 2.23, respectively).
4.a.- Present results showed that the proportions of COCs or DOs oocytes reaching M II were significantly increased (P<0.05 or P<0.01) in groups cultured with TCM-199 medium compared to Ham’s F-10 and RPMI-1640 groups {43.77% (for COCs)or 23.97% (for DOs) in TCM-199 Vs 39.60% (for COCs) or 18.44% (for DOs) in Ham’s F-10 and 34.34% (for COCs) or 12.52% (for DOs) in RPMI-1640, respectively}.
b- Also, meiotic maturation rate in COCs or DOs camel oocytes was significantly (P<0.05) increased in groups cultured in Ham’s F-10 compared to RPMI groups {39.60% (for COCs) or 18.44% (for DOs) Vs 34.34% (for COCs) or 12.52 % (for DOs), respectively}.
5- Present results showed that supplementation with gonadotropin hormones (PMSG + hCG) to culture media (TCM-199,
Ham’s F-10 and RPMI-1640) significantly (P<0.05) improved meiotic maturation rate of COCs or DOs camel oocytes than that of the control groups {42.29% (for COCs) or 20.58% (for DOs) Vs 36.18% (for COCs) or 16.04% (for DOs), respectively}.
6.a.- Present results showed that the proportions of COCs or DOs oocytes reaching M II were significantly elevated (P<0.01 or P<0.05) after 42 h of culture time compared to other maturation times; 28 or 32 h {57.39% (for COCs); 24.59% (for DOs) after 42h Vs 24.30% (for COCs); 11.96% (for DOs) after 28 h or 36.02 (for COCs); 18.38% (for DOs) after 32 h, respectively}.
b- Also, meiotic maturation rate in camel oocytes (COCs or DOs) significantly (P<0.05) increased after 32 h than those found after 28 h of maturation time {36.02% (for COCs); 18.38% (for DOs) after 32 h Vs 24.30% (for COCs); 11.96% (for DOs) after 28 h,}.
7.a.- Present results showed that the effect of interaction among types of media, supplementation of gonadotropins and different maturation times (28, 32 & 42 h) on the proportions of camel oocytes (COCs or DOs) at M II stage was not significant, although the highest proportion of oocytes reaching M II was found in TCM-199 medium groups supplemented with gonadotropins after 42 h of maturation time (63.96% for COCs and 32.08% for DOs).
b- Present results showed that the camel oocytes (COCs or DOs) cultured in TCM-199 medium supplemented with gonadotropins for culture periods of 28, 32 and 42 h exhibited non-significant increases of meiotic maturation rate compared to control groups (32.61; 47.12 and 63.96% for COCs Vs 19.13; 38.54 and 61.27%, respectively); (19.93; 25.9); 32.08% for DOs Vs 13.74; 22.22 and 29.49% respectively), although there were tendencies of the highest proportions of oocytes at M II after 42 h of culture period (63.96% for COCs and 32.08% for DOs).
c- Present results also indicated that the camel oocytes (COCs or DOs) cultured in Ham’s F-10 medium supplemented with gonadotropins for culture periods of 28, 32 and 42 h revealed non-significant increases of meiotic maturation rate compared to control groups (27.65; 38.27 and 60.67% for COCs Vs 19.96; 34.10 and 56.94, respectively); (15.55; 20.32 and 26.85% for DOs Vs 11.82; 16.11 and 20%, respectively), although, the oocytes cultured for the period of 42 h exhibited the highest proportion at M II (60.67% for COCs and 20% for DOs).
d- Moreover, present results also observed that the camel oocytes (COCs or DOs) cultured in RPMI-1640 medium supplemented with gonadotropins for culture periods of 28, 32 and 42 h exhibited non-significant increases of meiotic maturation rate compared to control groups (23.95; 32.26 and 54.12% for COCs Vs 22.50; 25.83 and 47.39%, respectively); (8.22; 15.83 and 20.55% for DOs Vs 2.50; 9.88 and 18.12%, respectively) although, the highest proportion of oocytes reaching M II was found after 42 h of culture period (54.12% for COCs and 20.55% for DOs).
8- Cumulus cells expansion was found to be more activated with TCM-199 treatment (P<0.05 or P<0.01) than those in Ham’s F-10 or RPMI-1640 treatments. Also, the supplementation of gonadotropins to culture media enhanced (P<0.05 or P<0.01) the full expansion rate of cumulus cells compared to control group. Moreover, the cumulus expansion was more pronounced after 42 h of culture time than those observed after 28 h or 32 h. However, the effect of interaction among the culture media, supplementation of gonadotropins and different maturation times (28, 32 and 42 h) on expansion of cumulus cells was not significant. Results also observed that cumulus cell expansion is not completely correlated with the oocyte IVM since some oocytes exhibited complete cell expansion while they did not achieve M II.
9- The effect of oocytes quality on IVM of camel oocytes was also investigated and the present results revealed that oocytes from COCs recorded higher meiotic maturation rate (P<0.05) compared to DOs (39.24% Vs 18.31%).
Conclusion:
from the present results, it can be concluded that:
• The favourable seasons for recovery of high quality of camel oocytes (COCs) which have a worthy competence to be matured in vitro, are winter and spring.
• The camel ovaries without corpus luteum (CL) contained higher numbers of quantity and best quality (COCs) of oocytes than do CL-bearing ovaries.
• TCM-199 was the most effective medium for meiotic maturation of camel oocytes than Ham’s F-10 or RPMI medium.
• Adding of gonadotropin hormones (PMSG + hCG) to culture media (TCM-199 or Ham’s F-10 or RPMI) resulted in higher meiotic maturation rates.
• A 42 h maturation period was superior for obtaining a higher frequency of camel oocytes at M II than 28 or 32 h.
• Oocyte quality is also an important factor for determining the in vitro maturation of camel oocytes. Present results indicated that oocytes from COCs revealed higher maturation rates compared to denuded oocytes.