ABSTRACT
Abstract. Background: The efficiency of ovine in vitro embryo production remains low yet. Aims: The present study evaluated the effect of different concentrations of gamma (γ)-oryzanol in maturation or culture media on in vitro ovine oocytes and embryo developments. Methods: Morphologically normal COCs were aspirated from ovine ovaries, subjected to maturation media supplemented with 0, 2.5, 5, 10, 20, 50, and 100 µM γ-oryzanol, then processed for conventional in vitro fertilization and culture to assess their potential to cleave and develop to blastocyst. Another group of COCs was matured and fertilized. Presumptive zygotes were subjected to culture in drops of media supplemented with 0, 2.5, 10, 20, and 50 µM γ-oryzanol, and the developments of embryos were assessed under 7% and 20% O2 levels. A control group of no supplementation was included in each experiment. Results: The expansion of cumulus cover and survival rate tended to decrease with concentrations of 20, 50, and 100 µM in maturation media, suggesting an overdose effect. The cleavage and total blastocyst rates were significantly higher for oocytes matured at 5 µM γ-oryzanol. The presumptive zygotes cultured in supplemented media showed significantly higher cleavage and total blastocyst rates with concentrations of 5 and 10 µM γ-oryzanol (P<0.04) in both 7% and 20% O2 levels. Conclusion: These results represent the first study showing a significant positive effect of the γ-oryzanol supplement on in vitro ovine oocyte and embryo development, at optimal concentrations of 5 µM in maturation, and 5 and 10 µM in embryo culture media.
ABSTRACT
OBJECTIVE: To investigate the relationship between polymorphism within the 5'-untranslated region (5'-UTR) of IGF-I gene and its periparturient concentration in Iranian Holstein dairy cows. METHODS: Blood samples (5 mL, n = 37) were collected by caudal venipuncture from each animal into sample tubes containing the EDTA and DNA was extracted from blood. In order to measure IGF-I concentration the collection of blood samples (n = 111) was also done at 14 d before calving (prepartum), 25 and 45 d postpartum. RESULTS: We found evidence for a significant effect of C to T mutation in position 512 of IGF-I gene on its serum concentration in dairy cows in Iran. Cows with CC genotype had significantly higher concentration (Mean±SD) of IGF-I at 14 d prepartum (91.8±18.1) µg/L compared to those with TT genotype (73.3±14.4) µg/L (P=0.04). A significant trend (quadratic) was found for IGF-I concentration, as higher in CC cows compared to ones with TT genotype, during the 14 d before calving to 45 d postpartum (P=0.01). CONCLUSIONS: We concluded that C/T transition in the promoter region of IGF-I gene can influence the serum concentration of IGF-I in periparturient dairy cows.