title: Combination of oocyte and zygote selection by brilliant cresyl blue (BCB) test enhanced prediction of developmental potential to the blastocyst in cattle.
abstract: The cumulus oocyte complexes (COCs) were obtained from local abattoir. After aspiration, the COCs were allotted into four treatments to evaluation of brilliant cresyl blue (BCB) test. Control treatment (C): oocytes were cultured directly (without exposure to BCB) after recovery in in vitro production (IVP) process. Oocyte treatment (OBCB): immediately after aspiration, COCs were incubated in modified Dulbecco's phosphate-buffered saline (mDPBS) supplemented with 26μM of BCB for 90min and classified into two classes: oocytes with blue cytoplasm coloration (OBCB+: more competent oocytes) and oocytes without blue cytoplasm coloration (OBCB-: low competent oocytes). Directly after classification, the oocytes were maintained undisrupted in the IVP process. Zygote treatment (ZBCB): After oocyte collection, maturation and fertilization, zygotes were stained with BCB for 10min and categorized into three ways, according to whether they were highly stained (ZBCB++: low competent zygotes), moderately stained (ZBCB+: moderate competent zygotes) and unstained (ZBCB-: more competent zygotes). Directly after classification, the zygotes were maintained undisrupted in the culture process. Oocyte and zygote treatments (OBCB/ZBCB): COCs were stained with BCB after recovery and classified into two classes (OBCB+ and OBCB-). After fertilization, the zygotes produced from OBCB+ and OBCB- oocytes were further stained with BCB for 10min and categorized six ways (OBCB+/ZBCB++, OBCB+/ZBCB+, OBCB+/ZBCB-, OBCB-/ZBCB++, OBCB-/ZBCB+ and OBCB-/ZBCB-). Directly after classification, the zygotes were maintained undisrupted in the culture process. The selection rate produced from OBCB treatment (OBCB+; 54.3%) was greater (P<0.05) than ZBCB treatment (ZBCB-; 44.3%). In addition, the selection rate produced from double application (combination of oocyte and zygote selection) of BCB test (OBCB+/ZBCB-: 28.8%) was less (P<0.01) than single application of BCB test (ZBCB-: 44.3%or OBCB+: 54.3%). The percentage of blastocyst production from OBCB+ oocytes (35.7%) and ZBCB- zygotes (36.6%) were greater (P<0.05) than that from C oocytes (25.7%), OBCB- oocytes (16.5%), ZBCB++ (13.5%) and ZBCB+ zygotes (21.3%). However, there were no significant differences (P>0.05) in the percentages of blastocyst production between OBCB+ oocytes (35.7%) and ZBCB- zygotes (36.6%). The proportion of blastocyst production from double application of BCB test (OBCB+/ZBCB-: 48.0%) was greater (P<0.05) than that from single application of BCB test (OBCB+: 35.7% or ZBCB-: 36.6%). In conclusion, current results confirmed that combination of oocyte and zygote selection by BCB test enhanced the efficiency of selecting for high quality embryos, compared to the single BCB test.
authors.affiliation: IVF & ET Laboratory, Department of Animal Science, Razi University, Kermanshah, Iran.
authors.forename: S M
authors.initials: SM
authors.lastname: Mirshamsi
authors.forename: H
authors.initials: H
authors.lastname: Karamishabankareh
authors.forename: M
authors.initials: M
authors.lastname: Ahmadi-Hamedani
authors.forename: L
authors.initials: L
authors.lastname: Soltani
authors.forename: H
authors.initials: H
authors.lastname: Hajarian
authors.forename: A R
authors.initials: AR
authors.lastname: Abdolmohammadi
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002417:Cattle; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods / Q000662:veterinary*; D054315:Oocyte Retrieval / Q000379:methods / Q000662:veterinary; D009865:Oocytes / Q000254:growth & development / Q000502:physiology*; D010078:Oxazines; D011247:Pregnancy; D015053:Zygote / Q000254:growth & development / Q000502:physiology*
chemical_list: D010078:Oxazines; C006797:Brilliant Cresyl Blue