Impact of hormonal modulation at proestrus on ovarian responses and uterine gene expression of suckled anestrous beef cows

Background： This study evaluated the impact of hormonal modulation at the onset of proestrus on ovarian response and uterine gene expression of beef cows.Methods： A total of 172 anestrous beef cows were assigned to one of four groups according to the treatment with estradiol cypionate（ECP） and/or equine chorionic gonadotropin（eCG） [CON（n = 43）, ECP（n = 43）, eCG（n = 44）and ECP ＋ eCG（n = 42）].Results： ECP-treated cows（ECP and ECP ＋ eCG groups） presented greater occurrence of estrus（44.6% vs. 65.4%; P = 0.01） and pregnancy per AI [47.1% vs. 33.3%; P = 0.07], but similar progesterone（P4） concentration at subsequent diestrus than cows not treated with ECP（CON and eCG groups）. Nonetheless, eCG-treated cows（eCG and ECP ＋ eCG groups） presented larger follicle at timed AI（12.6 ± 0.3 vs. 13.5 ± 0.3 mm; P = 0.03）, greater ovulation rate（96.5%vs. 82.6%; P = 0.008） and greater P4 concentration at d 6（3.9 ± 0.2 vs. 4.8 ± 0.2 ng/mL; P = 0.001） than cows not treated with eCG（CON and ECP groups）. Next, cows with a new corpus luteum 6 d after TAI were submitted to uterine biopsy procedure. Uterine fragments [CON（n = 6）, ECP（n = 6）] were analyzed by RNA-Seq and a total of 135 transcripts were differentially expressed between groups（73 genes up-regulated by ECP treatment）. Subsequently,uterine samples were analyzed by q PCR（genes associated with cell proliferation）. ECP treatment induced greater abundance of PTCH2（P = 0.07） and COL4 A1（P = 0.02）, whereas suppressed EGFR（P = 0.09） expression. Conversely, eCG treatment increased abundance of HB-EGF（P = 0.06）, ESR2（P = 0.09）, and ITGB3（P = 0.05）, whereas it reduced transcription of ESR1（P = 0.05）. Collectively, supplementation with ECP or eCG at the onset of proestrous of anestrous beef cows influenced ovarian responses, global and specific endometrial gene expression.Conclusion： Proestrus estradiol regulate the endometrial transcriptome, particularly stimulating proliferative activity in the endometrium.

Effect of Oocyte Recovery Techniques on in Vitro Production of Swine Embryos

In Vitro production of swine embryos is a valuable tool to generate clones and genetically modified pigs during a short period of time. However, the efficiency of the existing methods is extremely low and the oocyte quality and quantity represent important obstacles on the success of in Vitro production of embryos. Therefore, the aim of this study was to compare the in Vitro maturation, fertilization and subsequent embryo development rates of oocytes recovered by ovary slicing or follicular aspiration. The oocyte recovery rate (grade 1 COC/ovary) was higher (p = 0.0083) in the slicing group when compared to the aspiration group. No differences were observed between groups regarding in Vitro maturation and early cleavage rates. A higher percentage of oocytes recovered by follicular aspiration reached the blastocyst stage after IVF when compared to the ovary slicing method (p = 0.0395). However, no difference on blastocyst cell number was observed. Although the recovery of oocytes using the slicing technique yielded more grade 1 oocytes per ovary than the aspiration method, the number of oocytes that reached the blastocyst stage after IVF by the slicing method was lower when compared with oocytes obtained by aspiration, as observed by lower blastocyst rates. In conclusion, the follicular aspiration is the method of choice for porcine in Vitro embryo production.