Global proteomic analysis of pre-implantational ovine embryos produced in-vitro

The present study was conducted to characterize the major proteome of pre-implantation (D6) ovine embryos produced in vitro. COCs were aspirated from antral follicles (2-6 mm), matured and fertilized in vitro, and cultured until day six. Proteins were extracted separately from three pools of 45 embryos and separately run in SDS-PAGE. Proteins from each pool were individually subjected to in-gel digestion followed by LC-MS/MS. Three "raw. files" and protein lists were produced by Pattern Lab software but only proteins present in all three lists were used for the bioinformatics analyses. https://david.ncifcrf.govThere were 2,262 proteins identified in the 6-day old ovine embryos, including albumin, zona pellucida glycoprotein 2, 3 and 4, peptidyl arginine deiminase 6, actin cytoplasmic 1, gamma-actin 1, pyruvate kinase, heat shock protein 90 and protein disulfide isomerase, among others. Major biological processes linked to the sheep embryo proteome were translation, protein transport and protein stabilization, and molecular functions, defined as ATP binding, oxygen carrier activity and oxygen binding. There were 42 enriched functional clusters according to the 2,147 genes (UniProt database). Ten selected clusters with potential association with embryo development included translation, structural constituent of ribosomes, ribosomes, nucleosomes, structural constituent of the cytoskeleton, microtubule-based process, translation initiation factor activity, regulation of translational initiation, cell body and nucleotide biosynthetic process. The most representative KEEG pathways were ribosome, oxidative phosphorylation, glutathione metabolism, gap junction, mineral absorption, DNA replication and cGMP-PKG signaling pathway. Analyses of functional clusters clearly showed differences associated with the proteome of pre-implantation (D6) sheep embryos generated after in vitro fertilization in comparison with in vivo counterparts (Sanchez et al., 2021; https://doi.org/10.1111/rda.13897), confirming that the quality of in vitro derived blastocysts are unlike those produced in vivo. The present study portrays the first comprehensive overview of the proteome of pre-implantational ovine embryos grown in vitro.

Estradiol cypionate administered at the end of a progesterone-based protocol for FTAI induces ovulation and improves postovulatory luteal function and uterine environment in anestrous beef cows

The objective of this study was to evaluate the effect of the administration of estradiol cypionate (ECP) at the end of an estradiol and progesterone-based protocol for fixed time artificial insemination (FTAI) on ovarian response and uterine function in postpartum anestrous beef cows. Multiparous suckled cows were randomly assigned to receive ECP at doses of 0 (control, n = 15), 0.5 (n = 15) or 1.0 mg (n = 15) im at the time of progesterone intravaginal insert removal. Serum 17β-estradiol concentrations at 24 h after insert removal were greater (P < 0.05) in both ECP treatments than in controls. No differences in estradiol were found between 0.5 mg and control cows (P > 0.1) from 48 h after insert removal until ovulation, although greater (P < 0.05) concentrations were maintained until ovulation in 1.0 mg ECP treated cows. Maximum 17β-estradiol concentration attained in each female was greater as ECP dose was greater (10.4 ± 0.4, 11.8 ± 0.5 and 13.5 ± 0.7, for control, 0.5 and 1.0 mg ECP treated cows, respectively; P < 005). Proportion of cows that ovulated tended to be greater (P = 0.06) in ECP treated than in control cows. Ovulation occurred earlier and the size of the ovulatory follicle was smaller (P < 0.05) for 1.0 mg but not for 0.5 mg (P > 0.1) when compared with control cows. After ovulation (Day 13 and 14), serum progesterone concentrations were greater (P < 0.05) in 0.5 and 1.0 mg ECP than control cows. Uterine environment on Day 6 after ovulation was affected by treatment; transcript expression of three of nine evaluated genes (i.e., estrogen, IGF-1 and insulin receptors genes) were upregulated (P < 0.05) after ECP treatment. In conclusion, ECP administration at progesterone insert removal in anestrous cows i) induces greater serum estradiol concentrations and tended to induce greater ovulation rate, ii) acts in a dose-dependent manner, as ECP dose increases ovulation occurs earlier and the size of the ovulatory follicle is smaller, iii) improves postovulatory luteal function and affects uterine gene expression. Altogether, this information contributes with the understanding of the effect of preovulatory estradiol exposure on ovulation and postovulatory ovarian and uterine function in anestrous beef cows.

7 PREGNANCY RATES IN BEEF HEIFERS SYNCHRONIZED WITH A SHORTENED OESTRADIOL-BASED TREATMENT THAT PROVIDES FOR A PROLONGED PROESTRUS

An oestradiol-based protocol (named J-Synch) has been developed recently with the aim of providing for a longer proestrus, enhancing the development of the dominant follicle before ovulation, and increasing pregnancy rates following fixed-time AI (FTAI) in heifers (de la Matta and Bo 2012 Taurus 55, 17–23). Two experiments were performed in Uruguay with 1953 Angus × Hereford crossbred heifers to compare pregnancy rates obtained with the J-Synch protocol with the conventional 7-day oestradiol-based protocol. A secondary objective was to determine the effects of the time of FTAI and the addition of eCG at the time progestin device removal on pregnancy rates. In Experiment 1, 966 heifers received a DIB device (0.5 g of progesterone, Syntex, Buenos Aires, Argentina) plus 2 mg of oestradiol benzoate IM (Syntex) on Day 0. Heifers in the conventional treatment group (n = 485) received cloprostenol (500 μg, Ciclase DL, Syntex) and oestradiol cypionate (0.5 mg, Cipiosyn, Syntex) IM and had their DIB removed on Day 7 a.m. Heifers in this group were then subdivided to be FTAI on Day 9 a.m. or p.m. (i.e. 48 or 56 h after DIB removal). Heifers in the J-Synch treatment group (n = 481) received cloprostenol IM and DIB removal on Day 6 p.m. and received gonadotropin-releasing hormone (100 μg gonadorelin acetate, Gonasyn Gdr, Syntex) on Day 9 a.m.; heifers were then FTAI on Day 9 a.m. or p.m. (i.e. 60 or 72 h after DIB removal). All heifers in this experiment were also treated with 300 IU of eCG (Novormon, Syntex) at DIB removal. In Experiment 2, 987 heifers were treated with the J-Synch protocol as described in Experiment 1. At device removal (Day 6 p.m.), heifers were divided to receive (n = 488) or not (n = 499) 300 IU of eCG IM at that time and were further subdivided to receive gonadotropin-releasing hormone and FTAI on Day 9 a.m. or p.m. (i.e. 60 or 72 h after DIB removal). Pregnancy rates were determined by ultrasonography 30 days after FTAI. Data were analysed using logistic regression, and results are shown in Table 1. J-Synch-treated heifers tended (P < 0.1) to have higher pregnancy rates following FTAI, whereas time of FTAI only affected pregnancy rates following the conventional 7-day treatment (P < 0.05). However, removal of eCG from the J-Synch protocol in Experiment 2 resulted in reduced pregnancy rates when inseminations were done on Day 9 p.m. (P < 0.05). In summary, the addition of eCG to the J-Synch protocol provided for a wider window of insemination times facilitating FTAI in large groups of beef heifers. Table 1.Effect of length of progestin insertion, time of insemination and eCG treatment on pregnancy rates in beef heifers