The Developmental Potential of Oocytes is Impaired in Cattle with Liver Abnormalities

Abstract

Here, we investigated the effect of liver abnormality on the developmental potential of bovine oocytes. Good quality oocytes from healthy cows and from animals with a liver abnormality were matured and fertilized in vitro and then cultured to the blastocyst stage. On day 7 after fertilization, embryo cleavage and development were assessed. The concentrations of glucose, nonesterified fatty acid (NEFA), γ-glutamyl transpeptidase (γ-GTP), β-hydroxybutyrate (BHBA) and glutathione were measured in follicular fluids (FF). The proportion of good quality oocytes and the frequency of development to the blastocyst stage were lower in the liver anomaly group than those of the control group (P<0.05). The concentrations of γ-GTP and BHBA in the FF of the liver anomaly group were higher than those of the control group (P<0.05). The concentration of glutathione in the FF of the liver anomaly group was lower than that of the control group (P<0.05). Moreover, there was a negative correlation between these concentrations and the proportions of oocytes that developed to the blastocyst stage (P<0.05). Supplementation of the culture medium with γ-GTP or BHBA did not affect the rate of oocyte maturation but did cause a concentration-dependent reduction in the frequency of fertilized oocytes that developed to the blastocyst stage. Our findings indicate that the quality of oocytes and their potential for development are lower in cattle with liver disorders than those in healthy cattle; one possible cause may be the high concentration of γ-GTP and/or BHBA in their FF.