Reproductive seasonality influences oocyte retrieval and embryonic competence but not uterine receptivity in buffaloes

Author(s):Show less -

Barboza da Silva, Julio Cesar ^[1] ; Rodrigues Alves, Maira Bianchi ^[1] ; Bridi, Alessandra ^[1] ; Bohrer, Rodrigo Camponogara ^[2] ; Lamberti Escobar, Gabriela Sabine ^[2] ; Bernardes Afonso de Carvalho, Junia Aparecida ^[2] ; Bovi Binotti, Walter Alexandre ^[3] ; Pugliesi, Guilherme ^[4] ; Lemes, Kleber Menegon ^[5] ; Chello, Damiana ^[4] ; Perecin, Felipe ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Anim Sci & Food Engn, FZEA USP Dept Vet Med, Sao Paulo - Brazil

^[2] ABS Pecplan Minas, Gerais - Brazil

^[3] FS Fazenda Sesmaria, Sao Paulo - Brazil

^[4] Univ Sao Paulo, Fac Vet Med & Anim Sci, FMVZ USP Dept Anim Reprod, Sao Paulo, SP - Brazil

^[5] BI Boehringer Ingelheim, Sao Paulo - Brazil

• Document type: Journal article
• Source: Theriogenology; v. 170, p. 77-84, AUG 2021.
• Web of Science Citations: 0

Abstract

Since buffaloes are a seasonal, polyestrous species, optimizing reproduction during the non-breeding season is a key factor in increasing the reproductive and productive efficiency of herds. Ovum pick-up associated with in vitro embryo production and embryo cryopreservation is an alternative to reduce seasonal impacts. We studied the effects of seasonality in buffalo oocyte donors and embryo recipients during the favorable and non-favorable breeding seasons. Donors were evaluated for oocyte recovery and blastocyst production rate as dFBS (donors in favorable breeding season) or dNBS (donors in non-favorable breeding season). Embryos produced from dFBS or dNBS were cryopreserved by vitrification or the slow-freeze method for direct transfer and transferred to recipients in the favorable (rFBS) or non-favorable breeding season (rNBS). The heifers or cows were subjected to a fixed-time embryo transfer protocol and conception rates were determined on day 30 and on day 60. The oocyte recovery was lower in dFBS than in dNBS (7.6 vs. 10.0 oocyte/OPU, p = 0.0262); while no difference was found comparing blastocyst production rate (23.7% vs. 30.9% of blastocysts, respectively). Embryos from dFBS resulted in greater (p = 0.0013) conception rates on day 30 compared to dNBS (46.5% vs. 22.4%, respectively), despite the breeding season. The rFBS and rNBS treatments had similar (p = 0.6714) conception rates on day 30 (38.0% vs. 33.0%, respectively), indicating similar uterine receptivity. However, heifers on FBS had higher (p = 0.0003) conception rates on day 30 than cows (73.9% vs. 13.3%, respectively) when receiving em-bryos from dFBS. Vitrification and direct transfer had similar (p = 0.1698) conception rates on day 30 (30.4% vs. 41.4%, respectively). In conclusion, in vitro-produced embryos derived from dFBS were more competent in establishing pregnancy than dNBS counterparts, independent of recipients' reproductive seasonality. Heifers achieved better conception rates than cows during the favorable breeding season when the embryo came from dFBS. Cryopreserved in vitro produced embryos represent a reliable alternative to reduce seasonal variations in buffalo reproduction. The data elucidate the seasonal effects on embryo competence and on recipients' uterine receptivity, affording new strategies to implement ovum pick-up associated with in vitro embryo production programs in buffalo herds. (c) 2021 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 15/10606-9 - Innovations in the early pregnancy diagnosis in cattle
• Grantee: Guilherme Pugliesi
• Support Opportunities: Research Grants - Young Investigators Grants