201 LIVER AND KIDNEY FUNCTION IN BOVINE FETUSES FROM EMBRYOS PRODUCED IN VIVO OR IN VITRO

Abstract

Abnormal offspring syndrome can occur in fetuses and calves resulting from embryos produced in vitro or by nuclear transfer procedures. This study was conducted to determine the effects of in vitro embryo culture on fetal biochemistry profiles and histology of the liver and kidneys during late gestation. Embryos were produced in vivo by using superovulated cows (In Vivo) or in vitro by using a serum-containing culture system (In Vitro) as previously described (Miles et al. 2004 Biol. Reprod. 71, 1919–1926). Single blastocysts from each embryo production system were transferred nonsurgically into heifers. On Day 222 of gestation, fetuses from the In Vivo group (n = 12) and the In Vitro group (n = 12) were recovered in utero. Samples of fetal serum were collected for biochemical analysis. Samples of liver and kidney were prepared for histological evaluation. Stereological methods were used to determine the volume density of hepatocytes as well as kidney glomeruli and kidney tubules. Fetuses from the In Vitro group were heavier (P = 0.03) than those from the InVivo group (17.3 � 1.0 kg and 20.7 � 1.0 kg for InVivo and InVitro, respectively; least squares means � SEM). Liver and paired kidney weights per kilogram of body weight did not differ (P ≥ 0.10) with treatment (26.4 � 0.6 g kg–1 v. 27.6 � 0.6 g kg–1 and 7.8 � 0.5 g kg–1 v. 9.1 � 0.5 g kg–1 for liver and kidney, respectively). In addition, there was no effect of treatment on the volume densities of hepatocytes, kidney glomeruli, and kidney tubules. However, compared with the In Vivo group, fetuses from the In Vitro group had increased (P ≤ 0.02) concentrations of blood urea nitrogen (BUN; 13.8 � 1.8 mg dL–1 v. 19.8 � 1.8 mg dL–1) and BUN:creatinine ratio (4.6 � 0.8 v. 7.9 � 0.8). No differences were observed between the In Vivo and In Vitro groups for serum levels of creatinine, total bilirubin, total protein, albumin, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, glucose, insulin, and insulin-like growth factor-I. In summary, compared with bovine fetuses from in vivo-produced embryos, fetuses from in vitro-produced embryos had increased body weight, normal liver and kidney morphology, and increased concentrations of BUN during late gestation. Supported by the State of North Carolina.