225 Co-incubation with extracellular vesicles from follicular fluid of the breeding season improves the developmental competence of buffalo oocytes collected during the non-breeding season
M. Kosior A , M. Benitez Mora B , R. Esposito A , F. Piscopo A , M. Alfano A , G. Albero A , E. Capra C , A. Lange Consiglio D and B. Gasparrini AA Dipartimento di Medicina Veterinaria e Produzioni Animali, Università Degli Studi di Napoli Federico II, Naples, Italy
B Facultad de Ciencias Veterinarias, UNA, Asunción, Paraguay
C Istituto di Biologia e Biotecnologia Agrária, Consiglio Nazionale Delle Ricerche IBBA CNR, Lodi, Italy
D Dipartimento di Medicina Veterinaria, Università Degli Studi di Milano, Milan, Italy
Reproduction, Fertility and Development 35(2) 241-242 https://doi.org/10.1071/RDv35n2Ab225
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Reproductive seasonality is one of the factors affecting buffalo (Bubalus bubalis) farming profitability. During the non-breeding season (NBS), a decrease of the oocyte competence is reported (Di Francesco et al. 2011 Anim. Reprod. Sci. 123, 48–53). It is likely that seasonal variations occur in the follicular environment, thus accounting for the decreased oocyte competence. Follicular fluid (FF) contains extracellular vesicles (EVs) carrying bioactive compounds that may be involved in regulating oocyte developmental competence (da Silveira et al. 2017 PLoS One 12, e0179451). Therefore, the aim of this work was to evaluate whether co-incubation with EVs collected from FF during the breeding season (BS) may improve the developmental competence of COCs recovered during NBS in buffalo. Abattoir-derived ovaries were collected during the BS over five replicates. The FF of small (<5 mm) antral follicles (pool of 20) was aspirated, centrifuged (300 g × 10 min at 4°C, 2000 g × 10 min, 16500 g × 30 min) and the supernatant stored at −80°C until EV isolation through Exoquick precipitation (Sohel et al. 2013 PLoS One 8, e78505). Size and concentration of isolated EVs were determined by nanoparticle tracking analysis (NTA). Abattoir-derived COCs recovered during the NBS (n = 343, over five replicates) were in vitro matured in presence of different concentrations of EVs isolated from the FF in BS (0, 10 and 100 × 106/mL, on average 114/group), fertilised, and cultured to the blastocyst stage according to standard procedures (Gasparrini et al. 2000 Theriogenology 54, 1537–1542). Cleavage rate and embryo yields, in terms of total transferable embryos (TE), i.e. tight morulae and blastocysts, and fast-developing embryos (FDE, from blastocysts to hatched blastocysts) were assessed on Day 7. The differences among groups in the percentages of cleavage, TE, and FDE were analysed by chi-squared test. The average size and concentration of EVs were 212 nm and 2.17e + 11 particles/mL, respectively. No differences were found in cleavage rates among groups (on average 67%). The co-incubation with 10 × 106/mL EVs did not improve the percentages of TE compared with control in relation to the COCs (46.3 vs 34.1%, respectively) that increased when calculated in relation to cleaved oocytes (66.1 vs 48.9%, respectively; P < 0.05). However, a significant decrease (P < 0.05) of TE was observed with the higher concentration, i.e. 100 × 106/mL (18.5 and 29.4%, respectively in relation to COCs and cleaved). Furthermore, treatment with 10 × 106/mL EVs increased (P < 0.01) the percentage of FDE compared with the control both in relation to COCs (34.3 vs 19.4%, respectively) and cleaved (49.5 vs 26.6%, respectively); while the higher EVs concentration decreased (P < 0.01) the yields compared with both the other groups (9.7 and 14.1%, respectively in relation to COCs and cleaved). In conclusion, it was demonstrated the co-incubation with 10 × 106/mL EVs isolated from the FF of the BS improves the oocyte developmental competence of buffalo COCs collected during the NBS.
