Introduction and considerations
Whether you have frozen embryos in the NTS biobank or want to import embryos from another research institution, NTS may assist in the process of obtaining living animals.
Import of genetically modified animals from another facility or vendor poses a risk to the whole facility. Import of frozen embryos for direct implantation into pseudopregnant foster mothers, will often be a better alternative than import of living genetically modified mice for temporal housing in the quarantine unit, prior to rederivation. Frozen embryos do not pose the same risk to the facility as living animals, and a health report will not be required for imports of embryo.
In cases where the procedure is performed with embryos received from another institute, the service must include pathogen testing of the foster mother and offspring. Animals will be delivered with a health certificate tested for the absence of any pathogens listed by FELASA.
NTS also offers recovery from living animals (rederivation) or sperm (in vitro fertilization).
Benefits
- Recovery completed within 9-12 weeks.
- Mice produced are opportunistic pathogen-free (SOPF) and will come with the appropriate health report.
Provided by the customer
The paperwork involved for import of embryos or sperm are different from import of living animals. The customer will be responsible for the administration as well as all costs for transport of embryos. NTS may assist in the process, but will then charge the customer an extra administrative fee.
Requirements and time frame
- Satisfactory health report for the embryos is not required.
- Available for most strains. Total cost will be higher for strains known to be difficult to superovulate, fertilize and/or implant.
- NTS requires at least three straws/tubes of embryos.
- Embryos will be thawed and implanted into pseudopregnant foster mothers. Offspring will be separated at 3 weeks of age, biopsies taken and provided to customer.
- NTS expect confirmation of genotyping within a reasonable time (1 week).
- Foster mother and offspring will be tested against the presence of pathogens according to FELASA standards. Please contact NTS for a complete list of screened pathogens.
- The project is typically completed within 9-12 weeks.
Technical service performed by NTS
- NTS is responsible for the animal procedure permit (FOTS application).
- Planning and coordination of the project.
- Implantation into pseudo
- pregnant foster mothers, separation of offspring and collection of biopsies.
- Customer will receive biopsies in house. If personal pick-up is not an option, transport will be charged customer.
- Sample collection and coordination of pathogen screening.
Costs cover the following
- Cage cost for housing of foster mothers, vasectomized males, and offspring until 6 weeks of age.
- Test to confirm that animals are opportunistic pathogen-free (SOPF).
Guarantee
- Under certain conditions, such as when fewer than three offspring are born, NTS will repeat the procedure once for free.
Service Fees
Estimated costs for the above service can be found on our Service Fees page.
Extended description of the procedure
Planning and considerations
Instead of importing a living genetically modified (transgenic) mice for temporal housing in our animal facility (currently KPM at UIO), frozen embryos may be provided for direct implantation into pseudopregnant foster mothers. Embryos do not pose the same risk to the facility as living animals, and a health report will not be required for imports of embryos.
Provided by the customer
The customer must provide frozen embryos. Embryos that are either hetero-, hemi- or homozygote for the genetic modification may be transferred - as long as the genetic modification does not have a severe impact on fertilization or implantation efficiency.
The paperwork involved for import of embryos or sperm are different from import of living animals. The customer will be responsible for the administration as well as all costs for transport of embryos. NTS may assist in the process, but will then charge the customer an extra administrative fee.
Embryo recovery
A sufficient number of embryos will be thawed (usually one frozen tube). The obtained embryos will be transferred to pseudopregnant foster mothers. Blastocysts will be implanted in the uterus of pseudopregnant females upon embryo thawing. All other stages will be introduced into the oviduct. Biopsies will be taken from all resulting offspring before they are transported to the investigator (earliest at 3 weeks of age). The embryo recovery procedure is occasionally unsuccessful. If three or fewer living animals are recovered, NTS will repeat the procedure without additional cost.
Service provided by NTS included in the cost estimate
- Approval for the procedure (FOTS application).
- Organize transport of embryos (extra fee).
- Housing of foster mothers and vasectomized males.
- Thaw and implant into pseudopregnant foster mother.
- Separate foster mother and offspring.
- Take ear biopsies from offspring.
Cost
- NTS covers cage cost for purchase and transport of donor females, foster mothers, and all steps until offspring are 7 weeks of age.
- NTS normally charge a yearly storage fee for frozen strains in the NTS repository. NTS may also store frozen embryos provided by customers remaining after a successful embryo transfer. This storage will be free of charge as long as NTS has adequate capacity to store these embryos.
Special note: Due to the strict routines for preparation and conservation of cryopreserved embryos in liquid nitrogen, NTS can only guaranty successful recovery of embryos that are both frozen down and stored by NTS.