A physiological, rather than a superovulated, post-implantation environment can attenuate the compromising effect of assisted reproductive techniques on gene expression in developing mice embryos

Assisted reproductive techniques (ARTs) may perturb the pre-/peri-conception microenvironments, which subsequently threaten the health of offspring. This study aimed to investigate the effects of superovulation, vitrification, in vitro culture, and embryo transfer on the expression of epigenetic modulators, imprinted genes, and pluripotency markers in expanded blastocysts and Day-9.5 (D9.5) concepti. Results revealed that 53.4% (8/15) and 86.7% (13/15) of genes in the fetus and placenta, respectively, have similar patterns of transcription in all D9.5 concepti, despite the perturbed mRNA expression observed at the blastocyst stage for each embryo-production technique. These observations indicate a counterbalancing of the abnormal expression pattern analyzed at the blastocyst stage during post-implantation development, particularly when the uterus of a naturally synchronized foster mother is employed. Superovulation resulted in the most abnormal expression patterns compared to other treatment groups, although these same blastocysts were able to develop in a synchronized uterus. Thus, superovulation creates a hormonal environment that negatively affected gene expression and impairs fetal growth more adversely during post-implantation development than other ART protocols, such as in vitro culture, vitrification, or embryo transfer-although each did contribute negatively to the implantation and development process. Together, these results may have implications for treating infertility in humans.

IGF-I gene polymorphism, but not its blood concentration, is associated with milk fat and protein in Holstein dairy cows

We estimated the allele and genotype frequencies of IGF-I/SnaBI gene polymorphism and the concentration of this protein in Holstein dairy cows. We also examined the association with milk yield (305-day milk yield) and milk components (fat and protein percentage, and 305-day milk protein and fat yield). Blood IGF-I levels were measured and genotyping was performed on 250 Holstein cows of four different herds. In the association studies, traits of interest were analyzed using the GLM procedure of SAS; means of the IGF-I level among genotypes were compared by the LSMeans test. The AB and AA genotypes were the most (0.583-0.661) and least (0.083-0.192) frequent in the herds, respectively; the frequency of the BB genotype ranged from 0.201 to 0.333. The frequency of the A allele ranged from 0.375 to 0.495, while the frequency of the B allele ranged from 0.504 to 0.625, being the dominant allele. The mean level of IGF-I was 107 +/- 22 ng/mL for all groups, without any significant correlation with the production traits. Association of IGF-I/SnaBI genotypes with percentage of fat and protein in the milk was relatively high (P < 0.1 and P < 0.05, respectively); the AB genotype was superior to AA and BB genotypes. We concluded that this marker should be considered for milk component selection in Holstein dairy cattle.