273 Ovum Pickup at Different Times of a Synchronized Follicular Wave Did Not Affect Ivp in Bos Indicus, Bos Taurus, or Bubalus Bubalis

Abstract

One important factor in the success of ovum pickup (OPU)/IVP in Bos taurus is the follicular status at OPU concerning the dominance period (Hendriksen et al. 2000 Theriogenology 53, 11-20). The hypothesis of the present study is that OPU performed after follicle deviation, when follicles show a mild level of atresia, improves competence for IVP in Nelore (NE), Holstein (HO), and buffaloes (BU). Objectives were to determine effects of OPU done at different times of synchronized follicular wave (1, 3, or 5 d after expected emergence) and of genetic group (NE, HO, and BU) on IVP. A total of 27 heifers (9 of each genetic group) were maintained in contemporary nutritional and environmental conditions during experiment, in a cross-over design, performed in 6 replicates. Recovered oocytes with at least one cumulus cell layer were matured in TCM-199 supplemented with 10% of FCS plus 50 μM of cysteamin and 0.3 mM of cystine, at 38.5°C with 5% CO2 in air for 24 h. IVF was done with 2 × 106 spermatozoa per mL of NE (for bovine oocytes) or BU semen (for BU oocytes), for 20 h at the same incubator conditions of IVM. After IVF, presumptive zygotes were denuded and cultured in SOF under the same previous atmosphere conditions. Medium was changed 3 d after IVF when cleavage rate (CR) was assessed. Blastocyst (BR) and hatching rates (HR) were evaluated 7 and 9 days after IVF, respectively. About 50% of hatched blastocysts were fixed until nuclei counting. Data were analyzed by ANOVA using the Proc Mixed model. No effects of interaction or time of synchronization were observed in any of the variables. Concerning genetic group, NE had better results than HO and BU (mean ± SEM / heifer / replicate), respectively, for visualized follicles (41.0a ± 2.1, 22.1b ± 1.3, 18.8b ± 0.9), total oocytes (37.1a ± 2.5, 15.4b ± 1.2, 14.8b ± 1.0), oocytes at IVM (30.8a ± 2.4, 10.7b ± 1.0, 7.9b ± 0.7), oocytes at IVC (18.7a ± 0.8, 8.0b ± 0.5, 7.5b ± 0.4), cleaved embryos (15.4a ± 0.7, 4.6b ± 0.4, 4.4b ± 0.3),CR(81.8a, 59.1b, 62.3b), blastocysts on Day 7 (5.1a ± 0.6, 1.0b ± 0.2, 0.6b ± 0.1), BR (25.8a, 13.6b, 9.1b), and hatched blastocysts on Day 9 (2.6a ± 0.4, 0.3b ± 0.1, 0.3b ± 0.1). Recovery rate and HR were greater for NE (89.4 and 50.6%, respectively) than for HO (73.3 and 23.2%), but neither differed from BU (82.8 and 31.9%). Also, the percentage of viable was greater for NE (83.0) than for HO (66.9) and BU (53.1). No effects were observed for nuclei counting (NE = 176.6 ± 5.3, HO = 168.9 ± 13.7 and BU = 206.1 ± 23.1). Results demonstrate that Nelore had a better efficiency for IVP than Holstein and buffaloes. OPU performed at different times of synchronized follicular wave did not influence IVP, conversely to the initial hypothesis of this study. FAPESP (06/59550-6, 07/04782-2), Tortuga Cia Zootecnica®, Santa Adele and São Caetano Farms, LMMD, PCAPS, HOVET (Dr. Ubiraem Schalch), VRA, VNP (Prof. Dr. Francisco de Palma Rennó).

Reference Gene Selection for Gene Expression Analysis of Oocytes Collected from Dairy Cattle and Buffaloes during Winter and Summer

“…In order to obtain sufficient oocytes for the purpose of this work, follicle wave emergence was synchronized using a standard protocol before OPU, similarly as performed for cattle [33] . This protocol is based on the use of synthetic hormones that stimulate the synchronized growth of follicles to antral stage within five days of the beginning of the treatment [40] . Briefly, on random days of the estrous cycle (d0), buffaloes were treated with 2 mg of estradiol benzoate (Gonadiol, MSD Saúde Animal, Cotia, SP, Brazil), 530 µg of cloprostenol sodium (Ciosin, MSD Saúde Animal) i.m.…”

“…plus a norgestomet ear implant (Crestar, MSD Saúde Animal). The norgestomet implant was maintained for five days (until d5) when OPU was performed [40] . The two animal categories were subjected to two OPU sessions ( Figure 1 ), one during winter (N, n = 9; and M, n = 7) and one during summer (N, n = 8; and M, n = 11).…”

Short communication: Follicle superstimulation before ovum pick-up for in vitro embryo production in Holstein cows

“…Several studies have been conducted (Hendriksen et al, 2004;Machatkova et al, 2004;Gimenes et al, 2010Gimenes et al, , 2015 to determine the ideal follicular phase to maximize the performance of OPU. Machatkova et al (2004) found that the mean number of embryos per donor and the development rate of oocytes into blastocysts were greater in the growth phase than in the dominant phase.…”

Impact of in vitro fertilization by refrigerated versus frozen buffalo semen on developmental competence of buffalo embryos

“…Efficiency (OPU/IVEP) in buffalo is necessary to enhance the use of superior genetic material. OPU can be performed on prepubertal, anestrus, cycling and even pregnant buffalo, however, some anatomophysiological peculiarities, such as lower weight and size of ovaries compared to cows ( Vitoria, 1997 ), lower total primordial follicular number in buffalo when compared to cows ( Danell, 1987 ; Erickson, 1966 ; Baruselli et al, 1997 ; Gimenes et al, 2009 ; Campanile et al, 2010 ; Santos et al, 2013 and Liang et al, 2016 ), greater follicular rate atresia in buffaloes ( Le Van Ty et al, 1989 ; Ocampo et al, 1994 ; Perera, 2011 ; Santos et al, 2013 ), low eligibility rate for buffalo oocytes (38.4%) for the culture due to less compaction and fewer cumulus layers ( Ohashi et al, 2003 ; Gimenes et al, 2010 ; Marin et al, 2019 ) and the seasonality effects on the quality of oocytes ( Gimenes et al, 2010 ; Gasparrini, 2018 ) are limiting factors for in vitro embryo production (IVEP) in buffalo species ( Salzano et al, 2018 ; Baruselli et al, 2020 ).…”