Recovery and Preservation of Goat Follicular Oocytes

Introduction

Embryo-transfer has become the fastest method of genetic improvement of farm animals. In vitro maturation and in vitro fertilization (IVF) of follicular oocytes are the recent advances of embryo transfer, these are the important tools to study gamete physiology. From these techniques embryos can be obtained in abundant quantity, production of transgenic animal, embryo sexing, embryo splitting and multiplication of embryos in vitro on lines of superior offspring is possible by these methods.

The oocytes can be obtained from living animals as well as from slaughtered animals also. If those are collected from immature living animals and from immature slaughtered animals, in vitro matured, in vitro fertilized and transferred to the recipient the generation interval can be reduced. If the oocytes collected from varies of slaughtered animal the utility of that animal even after slaughter is improved. This also formulate low cost supply of follicular oocytes which can be matured, cultured and fertilized in vitro.


Material and Methods

Thirty three pairs of goat ovaries were obtained from, local slaughter house Parbhani immediately after slaughter: Paired ovaries were brought to the laboratory in a thermos flask containing 0.9 per cent normal saline at a room temperature: Normal saline is supplemented with Inj-Benzyl penicillin - 400 IU per m1' of saline: Inj-Streptomycin 200 mg/ml and 0.25 mg Nystatin. The pair of ovaries in various stages of oestrous cycle were classified as per (Zemjanis, 1970) into early luteal stage, luteal state and follicular stage. After recovery of oocytes, the good quality oocytes were selected and 65 oocytes were preserved in Ham’s F-10 medium with 10 per cent and 73 oocytes were preserved in 15 percent serum level at 5°C temperature for 24 hours. The ovaries were wahsed with normal saline and placed in a sterile petridish containing medium. The follicles measuring above 3mm in diameter were punctured with. The help of needle (19 guage) and contents were allowed to flow freely into the medium. The whole pertridish containing culture medium was observed under streoscopic microscope at 25 x in order to locate occytes.


Result and Discussion

The average numbers of follicles between 3-5 mm size in early luteal, luteal, and follicular stages were 4.30 + 0.37, 6.00 + 0.57 and 5.20 + 0.40; 3.00 + 1.00, 4.00 + 0.40 and 5.50 ± 0.22 respectively for 10 percent serum level and 15 percent serum level present findings are in agreement with those of Parkale (1987) an d Giri (1992) who reported them as 4.70, 4.95 and 4.32, 3.28, 4.33 and 4.02 respectively for corresponding stages of oestrous cycle in buffaloes. The present findings for early luteal and luteal stages are lower and for follicular stage in agreement with those. of Thakre (1993) who reported them as 5.60+ 0.35, 5.52 + 0.40 and 5.24 + 0.28 the corresponding stages of *estrous cycle in goat.
The overall average number of follicles per pair of ovaries irrespective of oestrous, stages and follicular sizes were 6,00+1.07 and 5.27+0.83 respectively, which are in agreement with those reported by Thakre (1993). These findings are higher than those reported by Parkale (1987) and Giri (1992) as 4.65 and 4.04 respectively.
Differences in the number of follicles may be due to differences in species, breeds, climatic conditions and endocrine profile etc of animals studied by different workers.
The average recovery rate follicular oocytes in early luteal, luteal and follicular stage for 10 per cent and 15 per cent serum levels was 73.33, 63.18 and 72.42] 66.66, 72.22 and 78.84 per cent respectively which are found to be higher than observations made by Giri (1992) and are in agreement with Thakare (1993) who reported them as 47.83, 58.24 and 47.20 and 76.84 per cent respectively which is in accordance with Lambert (1983) who reported 72-79 per cent by laproscopy method. The present findings are significantly higher than that reported by Leibfred and First (1979), Parkale (1987) and Giri (1992) who reported lower recovery rate of follicular oocytes as 50.00, 50.00 and 50.92 per cent respectively.
In the present study in Ham’s F-10 medium 65 medium 65 oocytes for 10 per cent serum level and 73 oocytes for 15 per cent serum level were preserved at 5oC for 24 hours, it was observed that there was no significant change recorded in the morphology of oocytes.


References

1. Giri, C.G. (1992): Characterisation and morphological in vitro maturation of bulffalo follicular oocytes in different culture media. M.V.Sc. Thesis, Kokan Krishi Vidapith,Dapoli.
2. Lambert R.D. : Sirad, M.A. Benard, C; Beland, R.; Riouz J.E. Lecierc, P : Manard D.P. and Bedoya M. (1986): In vitro fertilization of bovine oocytes matured in vitro and collected at laproscopy. Heriogenology 25 (1): 117.
3. Leidfired, L. and First, N.L. (1979): Characterization of bovine follicular oocytes and their ability to mature in vitro J. Anim Sci. 48 (1): 76-86.
4. Parkale, D.D. (1987): Studies on buffalo (bos bubalis) avaries, follicles and follicular oocytes with special references to culture of oocytes in vitro M.V.Sc. Thesis, Kokan Krishi Vidyapith Dapoli.
5. Thakare N.V. (1993): Studies on recovery, characterization and morphological in vitro maturation of goat follicular oocytes in different culture media. M.V. Sc. Thesis, M.A.U. Parbhani.


by : Khillare, K.P.
from : http://www.veterinaryworld.org