Metabolic Regulation and Cryotolerance of In Vitro-Produced Holstein Embryos

<p><em>In vitro</em> production and transfer of embryos has become a common practice within the dairy industry to efficiently breed superior animals and meet the consumption demand of the growing population. Cyropreservation is necessary for the application of commercialized embryo transfer, however, <em>in vitro</em>-produced embryos show morphological and physiological defects which negatively impact their ability to withstand cryopreservation in comparison to their <em>in vivo </em>counterparts. These artifacts result from culture conditions that cause stress to the embryo during development, leading to an accumulation of intracellular lipids, mitochondrial dysfunction, and ultimately poor ability to withstand freezing and thawing. The objective of these studies was to examine the effects of various metabolic regulators on the viability and cryotolerance of <em>in vitro</em>-produced embryos. Pilot studies revealed that evaluating early (stage 6) versus late (stage 7) blastocysts did not affect the trend seen in results, nor did culturing embryos in continuous versus sequential media. From the main experiment performed, it was concluded that a combination of metabolic regulators decreased lipid content, improved cryopreservation survival, and lowered the percentage of apoptotic cells present after thawing. Conditioned media increased the blastocyst percentage, but did not produce superior quality embryos as measured by cryotolerance. Research concerning the metabolic needs of the preimplantation embryo must continue to determine more relevant markers of embryo quality <em>in vitro</em>.</p>

Name thesis:degree_name

MS in Agriculture - Animal Science

Discipline thesis:degree_discipline

Animal Science

Year dc:date.available

2016

Author dc:creator

• Roberts, Melissa Ann

Contributors dc:contributor

• Fernando Campos-Chillon

• bovine
• embryo
• metabolism
• cryopreservation
• Animal Sciences

Identifier

10.15368/theses.2016.162

OAI identifier oai:identifier

oai:digitalcommons.calpoly.edu:theses-2888