160 EFFECT OF BSA SOURCES AND TYPES ON IN VITRO-PRODUCED LIVESTOCK EMBRYO DEVELOPMENT

Abstract

Bovine serum albumin (BSA) is a macromolecule supplement used in embryo and cell culture media. Other chemicals have been used as macromolecule substitutes in embryo culture with variable effectiveness. There are BSA products available that are defined in their disease status, collection method, and manufacturing process. They are compliant for use in raw form or in culture medium in the USA and EU. It was the purpose of this study to compare the effectiveness of highly defined and internationally compliant BSA with typically used BSA on in vitro-produced pig and cow embryo development. Pig oocyte-cumulus complexes were matured in two stages for 44 h in vitro. Semen from one boar of known high fertility was used across the study to fertilize mature oocytes. After 6-h co-incubation with sperm (50 motile sperm/oocyte), presumptive zygotes were cultured for 120 h in modified NCSU-23 containing 4 mg/mL of one of the following heat-shocked BSA fractions: Sigma A-7906 (control), Minitube Reproductive Biology Grade Fraction-V (RBG-V1, RBG-V2, RBG-V3), or Minitube Reproductive Biology Grade Fatty Acid-Free (RBG-FAF1). Across all treatments, Day 5 morulae were removed from BSA culture and placed into modified NCSU-23 with 10% fetal bovine serum (FBS) (no BSA) and cultured for 48 h. After 168-h total culture, the following blastocyst development was observed: Sigma A-7906, 12.3% (40/324); RBG-V1, 21.1% (36/171); RBG-V2, 19.0% (30/158); RBG-V3, 16.8% (27/161); and RBG-FAF1, 13.4% (21/157). These data show that culture medium supplemented with Minitube Reproductive Biology Grade BSA meets or exceeds (P < 0.05; ANOVA-GLM of SAS; SAS Institute, Inc., Cary, NC, USA) blastocyst development potential when compared to culture medium supplemented with undefined standard BSA preparations, such as Sigma A-7906. In vitro-matured cow cumulus-oocyte complexes were fertilized and cultured in one of two CR-1aa-based media. Oocytes were fertilized in IVF medium containing 6 mg/mL Sigma A-8806 (FAF) or 6 mg/mL Minitube RBG-FAF1. After 24 h in IVF medium, presumptive zygotes from a specific BSA-supplemented medium were cultured for 144 h in CR-1aa supplemented with their respective BSA (8 mg/mL). Day 6 morulae were removed from BSA culture and placed into CR-1aa with 10% FBS (no BSA) and cultured for 48 h. After 192-h total culture, the following blastocyst development from oocytes matured was observed: Sigma A-8806, 21.4% (88/411); RBG-FAF1, 18.9% (70/370). These data show that culture medium supplemented with Minitube Reproductive Biology Grade BSA meets blastocyst development potential (P > 0.05) when compared to culture medium supplemented with undefined standard BSA preparations, such as Sigma A-8806. The inclusion of internationally compliant BSA meets or exceeds blastocyst development rates in comparison to standard BSA preparations in common in vitro embryo production systems for swine and cattle. Although manufacturing differences remain the prominent variant in BSA sources and types, continued monitoring and documentation of BSA preparations tested in livestock in vitro embryo production systems will ensure a safe global supply of BSA products for future culture media production.