Diferentes alternativas de estimulación ovárica para producción in vitro de embriones en búfalas

BANDEO A. S.; KONRAD J.L; VALLEJOS N; PONCE P.; SANSIÑENA M; CRUDELI G.; MALDONADO VARGAS, P.

Caracas

Simposio; 13th WORLD BUFFALO CONGRESS; 2023

INTERNATIONAL BUFFALO FEDERATION GOVERNING BODY

ABSTRACTCurrently, one of the most promising tools to increase thenumber of transferable embryos in buffaloes is in vitro production (IVP). However, IVP still has certain limitations that prevent its optimal efficiency for commercial application. One ofthese limitations is the reduced number and low competenceof oocytes obtained from transvaginal follicular aspiration inthis species. It has been found that ovarian stimulation withfollicle-stimulating hormone (FSH) before aspiration improvesthe technique’s efficiency, primarily due to the increased competence of the obtained oocytes. The objective of this studywas to evaluate the response to different hormonal stimulationtreatments in buffalo donors, their effect on oocyte quality, andsubsequent embryo production. This field study was conductedat the Pedro Antonio Silva buffalo farm, located in the GeneralPaz department, Province of Corrientes, in 2021. A total of 60OPU sessions were performed on Murrah and Mediterraneanbreed donors, and four ovarian stimulation treatments were applied. Treatment (TRT) 1, which was used as control (n=20),consisted of a day 0 insertion of an intravaginal progesteronedevice (IP) + 2 mg estradiol benzoate (EB) i.m., with OPU performed on day 7. Treatment (TRT) 2 (n=10) consisted of day0 insertion of IP + 2 mg EB, followed by four applications ofFSH (Folltropin-V®) i.m. with a total of 160 mg distributed indecreasing doses every 12 hours for two days (50mg, 50mg,30mg, 30mg), OPU was then performed 36 hours after the lastapplication. Treatment (TRT) 3 (n=20) consisted of day 0 insertion of IP + EB, followed by a day 4 application of 1050 IUof recombinant eCG (FoliRec®) i.m., OPU was performed onday 7; Treatment (TRT) 4 (n=10) consisted of day 0 insertionof IP + EB, followed by day 4 application of 2500 IU of serumeCG (Ecegon®) i.m., OPU was performed 72 hours later. Prior to each follicular aspiration, antral follicles were counted usinga portable ultrasound with a linear probe (Mindray, DP30-Vet)and classified into small (≥3mm Ø), medium (4-8 mm Ø), andlarge (>8mm Ø) follicles. The aspirated oocytes or COCs (cumulus-oocyte complexes) were classified into grades (1 to 4)based on the number of cumulus layers present, according tothe International Embryo Transfer Society method (IETS Manual). In vitro fertilization (IVF) was performed after 24 hours ofoocyte in vitro maturation using cryopreserved semen from buffalo bulls of proven fertility. In vitro culture (IVC) was carried outfor 6.5 days, and all embryos that reached the blastocyst stagewere graded and vitrified. Descriptive statistics and analysisof variance were conducted on the obtained data, consideringpopulation and follicular size, quantity and quality of oocytes,and embryo production, with a significance level (α) of 5%. Thetotal observed follicular population did not differ among treatments (p>0.05). However, stimulation in TRT2 (FSH) and TRT4(serum eCG) increased the proportion of medium-sized follicles (4-8mm) available for OPU (p