The developmental capacity of oocytes from prepubertal cattle is reduced compared with their adult counterparts, and epigenetic mechanisms are thought to be involved herein. Here, we analyzed DNA methylation in three developmentally important, nonimprinted genes (SLC2A1, PRDX1, ZAR1) and two satellite sequences, i.e. 'bovine testis satellite I' (BTS) and 'Bos taurus alpha satellite I' (BTaS). In parallel, mRNA expression of the genes was determined by quantitative real-time PCR. Oocytes were retrieved from prepubertal calves and adult cows twice per week over a 3-week period by ultrasound-guided follicular aspiration after treatment with FSH and/or IGF1. Both immature and in vitro matured prepubertal and adult oocytes showed a distinct hypomethylation profile of the three genes without differences between the two types of donors. The methylation status of the BTS sequence changed according to the age and treatment while the methylation status of BTaS sequence remained largely unchanged across the different age and treatment groups. Relative transcript abundance of the selected genes was significantly different in immature and in vitro matured oocytes; only minor changes related to origin and treatment were observed. In conclusion, methylation levels of the investigated satellite sequences were high (O50%) in all groups and showed significant variation depending on the age, treatment, or in vitro maturation. To what extent this is involved in the acquisition of developmental competence of bovine oocytes needs further study.

The aim of this study was to investigate whether plasma anti-Muellerian hormone (AMH) levels of Holstein-Friesian heifers could be used to predict ovum pick-up (OPU) and embryo production outcomes. Plasma samples and data were collected from 64 heifers, which underwent repeated OPU with subsequent in vitro embryo production followed by embryo flushing after superovulation. AMH levels were significantly positively correlated with the number of follicles aspirated per OPU session (r = 0.45), recovered oocytes per OPU (r =0.43) and in vitro produced embryos per OPU (r = 0.28). No significant correlations between AMH and in vivo produced embryos were ascertained. Our results suggest that correlations between AMH and outcomes of an OPU-IVF program are too low to use AMH as a precise predictive parameter for the success of a particular OPU procedure in Holstein-Friesian heifers. However, AMH can help to identify groups of very good or very poor oocyte donors.

Cyclic adenosine monophosphate (cAMP) modulators have been used to avoid spontaneous oocyte maturation and concomitantly improve oocyte developmental competence. The current work evaluated the effects of the addition of cAMP modulators forskolin, 3-isobutyl-1-methylxanthine (IBMX) and cilostamide during in vitro maturation on the quality and yields of blastocysts. The following experimental groups were evaluated: (i) slicing or (ii) aspiration and maturation in tissue culture medium (TCM)199 for 24 h (TCM24slicing and TCM24aspiration, respectively), (iii) aspiration and maturation in the presence of cAMP modulators for 30 h (cAMP30aspiration) and in vivo-produced blastocysts. In vitro-matured oocytes were fertilized and presumptive zygotes were cultured in vitro to assess embryo development. Cleavage, blastocyst formation, blastocyst cell number, mRNA abundance of selected genes and global methylation profiles were evaluated. Blastocyst rate/zygotes for the TCM24aspiration protocol was improved (32.2 ± 2.1%) compared with TCM24slicing and cAMP30aspiration (23.4 ± 1.2% and 23.3 ± 2.0%, respectively, P 0.05), while those from the other groups were significantly elevated. It is concluded that retrieval, collection systems and addition of cAMP modulators can affect oocyte developmental competence, which is reflected not only in blastocyst rates but also in global DNA methylation and gene expression patterns.

Despite recent advances in NOTES, NOS, SILS and related techniques, the feasibility of performing extensive surgery is still limited. Colon surgery usually requires additional access sites or complex technical means for triangulation and retraction. A method is presented that enables single-port colon surgery, supported by flexible colonoscopy. Single-port sigmoidectomy was performed in five cases on the porcine model. Flexible colonoscopy was used to manoeuvre the colon and expose its mesentery for dissection. The specimen was retrieved transrectally by invagination. Single-port sigmoidectomy supported by colonoscopy was feasible in all cases. The method provided a fixed framework, excellent organ guidance and exposition of the mesentery and enabled bowel-close mesocolic preparation. The access angle for preparation and visualisation could be altered during the procedure using the colonoscope. During autopsy on day 21, competent anastomotic healing with only rare interenteric adhesions was observed. One animal had a small preperitoneal abscess in the umbilical region while demonstrating completed skin healing. Flexible colonoscopy provided a fixed reference frame that enabled single-port preparation and dissection of the sigmoid colon. Under colonoscopic guidance, the access angle for dissection could be adapted according to the surgeon's needs. The procedures could be performed safely and effectively.

The presented study shows that pure NOTES resection and anastomosis of the large bowel are feasible. Intraluminal organ manipulation provided excellent organ exposition and rendered one additional access site unnecessary. Transgastric preparation was shown to be safe and effective.