title: Effect of energy source during culture on in vitro embryo development, resistance to cryopreservation and sex ratio.
abstract: The aim of this work was to evaluate whether minimizing the glucose concentration during culture or replacing the hexose with other energy substrates and/or embryotrophic compounds would affect the in vitro development, the resistance to cryopreservation and the sex ratio of bovine embryos. In vitro matured and fertilized oocytes were randomly assigned to 4 groups for in vitro culture, that differed in the energy substrates included: group A) 1.5 mM glucose, as in standard SOF; group B) 0.15 mM glucose; group C) 0.125 mM G3P, in the presence of 0.15 mM glucose and group D) 0.34 mM citrate, in combination with 2.77 mM myo-inositol. Blastocysts were evaluated on day 7, then vitrified by cryotop in 16.5% DMSO, 16.5% EG and 0.5 M sucrose and warmed in decreasing concentration of sucrose (0.25 to 0.15 M sucrose). The survival rates were assessed after 24 h in vitro culture. Finally, the blastocysts produced were sexed by PCR. An increased blastocyst rate was recorded in groups B, C and D, i.e., when glucose concentration was reduced, compared to group A (28.2, 41.0, 35.7 and 35.8, respectively in groups A, B, C and D; P < 0.01). However, the embryos cultured in group D showed the slowest developmental speed, indicated by the lowest percentage of advanced stage-embryos (expanded and hatched blastocysts) out of the total blastocysts (56.1, 45.8, 56.9 and 31.8 %, respectively in groups A, B, C and D; P < 0.01). Furthermore, survival rates after 24 h culture of vitrified-warmed blastocysts also decreased in group D (73.3, 73.1, 71.4 and 58.4%, respectively in groups A, B, C and D; P < 0.01). Interestingly, in group D a higher percentage of female embryos was obtained compared to group A, with intermediate values in groups B and C (45.6, 53.4, 50.0 and 61.5%, respectively in groups A, B, C and D; P < 0.05). In conclusion, it was demonstrated that the energy substrate during in vitro culture affects both the production and the viability of blastocysts. Furthermore, manipulating the metabolic profile of embryos during in vitro culture may have an impact on sex ratio.
authors.affiliation: DISCIZIA, Faculty of Veterinary Medicine, Federico II University, Napoli, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Rubessa
authors.forename: Lucia
authors.initials: L
authors.lastname: Boccia
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Campanile
authors.forename: Valentina
authors.initials: V
authors.lastname: Longobardi
authors.forename: Sara
authors.initials: S
authors.lastname: Albarella
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tateo
authors.forename: Luigi
authors.initials: L
authors.lastname: Zicarelli
authors.forename: Bianca
authors.initials: B
authors.lastname: Gasparrini
mesh_terms: D000818:Animals; D002417:Cattle; D019343:Citric Acid / Q000378:metabolism / Q000494:pharmacology; D015925:Cryopreservation / Q000662:veterinary*; D003470:Culture Media / Q000494:pharmacology; D046149:Embryo Culture Techniques / Q000379:methods / Q000662:veterinary*; D004622:Embryo, Mammalian / Q000378:metabolism*; D047108:Embryonic Development / Q000187:drug effects*; D004734:Energy Metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005986:Glyceraldehyde 3-Phosphate / Q000494:pharmacology; D007294:Inositol / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D012744:Sex Ratio; D013395:Sucrose / Q000378:metabolism / Q000494:pharmacology
chemical_list: D003470:Culture Media; D005986:Glyceraldehyde 3-Phosphate; D019343:Citric Acid; D007294:Inositol; D013395:Sucrose; D005947:Glucose