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Large scale commercial application of bisection of sheep embryos
THERIOGENOLOGY
LARGE
SCALE COMMERCIAL H. William
APPLICATION
Vivancol,
OF BISECTION
Raymundo
and Adrian
RangelL, 3
OF SHEEP EkiiRYOS
Peter Lynch1
Phcdes
1 LambXL, P 0 Box 213, Palmerston North, 2 Massey University, Department of Animal Science, 3 Agrivet, New Zealand
The objective was to introduce within the commercial embryo transfer multiplication programme of the Texel sheep breed at La&XL - New Zealand an embryo splitting system to increase the lamb crop. A Leitz micromanipulator was adapted by using only the left arm controls and fitting into it either our own made plastic holder to which a broken razor blade was glued having the sharp edge parallel to the splitting dish or by using a commercial microblade produced by A.B. Technology Limited, Australia..The micromanipulator was mounted besides an inverted microscope in a bench which was cemented with a concrete column into the ground to Embryos were flushed with an energy-supplemented avoid vibration. PBS containing (glucose lg, sodium pyruvate 0.036g x 1lt)Dulbecco's 10% sheep serum. Only expanded blastocyst and hatched blastocyst of good quality were bisected. The embryos before they were placed into the splitting drop were held for 30 to 60 sec. in a media similar to the flushing media but with the sheep serum increased to a level of 20%. The microdrop for splitting was a simple PBS drop without covering with paraffin oil. Embryos were bisected without using holding pipettes. The bisections were made during the ET season from middle of March to end of June 1990. Recipients were multiparous Romney ewes implanted with either 2 whole embryos or with 2 demi embryos in the uterine horn ipsilateral to the ovulation side. All recipients were in the same farm and were supplemented with progesterone (Cidr-G; Carter Holt Harvey, N.Z.) from time of implantation up to 56 days after transfer when they were pregnancy diagnosed by ultrasound scanning. Data on embryo survival is presented in the following table:
Type of embryo
Total NO. of embryos implanted
Total No. of foetuses scanned
Embryo survival (%l of the of the of the denies whole original whole
710 Demi 1410 50.3 100.6 1252 771 61.6 61.6 Whole _____________________~~____~~~__~~-~_~~~~~~_~_~_~_______________From the total 1252 whole embryos implanted, 1010 embryos were of high quality (grades 1 and 2) and 242 were of low quality (grade 3). Results indicate the feasibility of the use of embryo bisection High survival rates can be in large scale ET prograrmnes in sheep. expected from high quality (grade 1) expanded and hatched blastocysts bisected as described in this report.
292
JANUARY
1991 VOL. 35 NO. 1
LARGE
SCALE COMMERCIAL H. William
APPLICATION
Vivancol,
OF BISECTION
Raymundo
and Adrian
RangelL, 3
OF SHEEP EkiiRYOS
Peter Lynch1
Phcdes
1 LambXL, P 0 Box 213, Palmerston North, 2 Massey University, Department of Animal Science, 3 Agrivet, New Zealand
The objective was to introduce within the commercial embryo transfer multiplication programme of the Texel sheep breed at La&XL - New Zealand an embryo splitting system to increase the lamb crop. A Leitz micromanipulator was adapted by using only the left arm controls and fitting into it either our own made plastic holder to which a broken razor blade was glued having the sharp edge parallel to the splitting dish or by using a commercial microblade produced by A.B. Technology Limited, Australia..The micromanipulator was mounted besides an inverted microscope in a bench which was cemented with a concrete column into the ground to Embryos were flushed with an energy-supplemented avoid vibration. PBS containing (glucose lg, sodium pyruvate 0.036g x 1lt)Dulbecco's 10% sheep serum. Only expanded blastocyst and hatched blastocyst of good quality were bisected. The embryos before they were placed into the splitting drop were held for 30 to 60 sec. in a media similar to the flushing media but with the sheep serum increased to a level of 20%. The microdrop for splitting was a simple PBS drop without covering with paraffin oil. Embryos were bisected without using holding pipettes. The bisections were made during the ET season from middle of March to end of June 1990. Recipients were multiparous Romney ewes implanted with either 2 whole embryos or with 2 demi embryos in the uterine horn ipsilateral to the ovulation side. All recipients were in the same farm and were supplemented with progesterone (Cidr-G; Carter Holt Harvey, N.Z.) from time of implantation up to 56 days after transfer when they were pregnancy diagnosed by ultrasound scanning. Data on embryo survival is presented in the following table:
Type of embryo
Total NO. of embryos implanted
Total No. of foetuses scanned
Embryo survival (%l of the of the of the denies whole original whole
710 Demi 1410 50.3 100.6 1252 771 61.6 61.6 Whole _____________________~~____~~~__~~-~_~~~~~~_~_~_~_______________From the total 1252 whole embryos implanted, 1010 embryos were of high quality (grades 1 and 2) and 242 were of low quality (grade 3). Results indicate the feasibility of the use of embryo bisection High survival rates can be in large scale ET prograrmnes in sheep. expected from high quality (grade 1) expanded and hatched blastocysts bisected as described in this report.
292
JANUARY
1991 VOL. 35 NO. 1