2018: TAUROURSODEOXYCHOLIC ACID SUPPLEMENTATION IMPROVES BOVINE IN VITRO FERTILIZATION RATES


 

Tauroursodeoxycholic acid supplementation improves bovine in vitro fertilization rates 
Y.L. Lee,a E.K. Kennedy,a Y.J. Chung,a J.E. Graham,a M.S. Roberson,b S.H. Cheonga 

aDepartment of Clinical Sciences and bDepartment of Biomedical Sciences, College of Veterinary 
Medicine, Cornell University, Ithaca, NY 

  
Bile acids are traditionally known for their role in lipid digestion and absorption but recently have 

been shown to be endocrine signaling molecules. In an observational study, women with high levels of 
ursodeoxycholic acid in follicular fluid had oocytes with better developmental potential. Another study 
showed that supplementation of the taurine conjugated ursodeoxycholic acid (TUDCA) to bovine 
embryos during the culture phase improves resistance to endoplasmic reticulum stress and increases 
development rates. The effects of supplementation during the maturation phase, where the oocytes are in 
contact with follicular fluid have not been studied; therefore, the aim of our study was to determine the 
effects of TUDCA supplementation during the maturation phase or culture phase on embryo development 
rates. We hypothesized that TUDCA supplementation during maturation phase improves embryo 
development.  

 
Study design 
 Bovine oocytes were collected from slaughterhouse ovaries and assigned to one of 4 treatment 
groups: Control group with no TUDCA exposure, in vitro maturation (IVM) group supplemented with 
200 µM of TUDCA during the oocyte maturation phase only, in vitro culture (IVC) group supplemented 
with 200 µM TUDCA during the embryo culture phase only, and IVM/IVC group which were 
supplemented with 200 µM TUDCA during the maturation and culture phases of embryo production. 
Embryos were evaluated on days 3, 7 and 10 after fertilization to determine cleavage, blastocyst, and 
hatched blastocyst rates, respectively. The effects of treatment on cleavage, blastocysts and hatched 
blastocyst rates were determined using a mixed-model ANOVA (PROC GLIMMIX) of SAS version 9.4. 
Treatment was the fixed effect and the effect of week was included as a random variable to control for 
replicate variability. Post-hoc Tukey test was used to determine differences between treatment groups. 
 
Results 
 A total of 896 embryos were included in the study. There were no differences in cleavage rates 
between treatment groups (P=0.44). Blastocyst rates were higher in the IVM group (60% of cleaved 
embryos) compared with the Control group (42% of cleaved embryos; P=0.0004) and the IVC group 
(40% of cleaved embryos; P=0.006); and tended to be higher than the IVM/IVC group (47% of cleaved 
embryos; P=0.07). The hatch blastocyst rates were higher in the IVM group (P=0.02) compared with the 
IVC group and tended to be higher compared with the Control group (P=0.08). 
 
Discussion/conclusion 
 We found that TUDCA supplementation during the IVM stage improved blastocyst rates and 
tended to improve hatched blastocyst rates compared with the control group. We did not observe an 
improvement of blastocyst rates in the IVC group compared with the control group in our study. TUDCA 
may have application as a supplement for bovine in vitro fertilization to improve embryo development 
rates. 
 
Acknowledgment 
 This work was supported by the USDA National Institute of Food and Agriculture, Research 
Animal Health project NYCV-480867.  
 
Keywords: Tauroursodeoxycholic acid, in vitro fertilization, bovine 

Clinical Theriogenology • Volume 10,  Number 3 • September 2018303