Relationship of antral follicular blood flow velocity to superovulatory responses in ewes

Abstract

The aim of this study was to examine the association between antral follicular blood flow velocity and the response of ewes to hormonal ovarian superstimulation. Ten Santa Inês ewes were subjected to a short- (7days; Group 1) or long-term (13days; Group 2) progesterone (CIDR; InterAg, Hamilton, New Zealand) priming, and a superovulatory treatment with porcine follicle-stimulating hormone (pFSH; Folltropin-V; Bioniche Animal Health, Belleville, ON, Canada), given twice daily for four consecutive days in decreasing doses and initiated four or ten days after CIDR insertion, respectively. Embryos were recovered surgically seven days after the last pFSH dose. From one day prior to until the end of the pFSH regimen (Days -1 to 3), all ewes underwent daily transrectal ultrasonography of ovaries. The number of high-velocity pixels (HVPs; 0.055-0.11m/s or upper 50% of recordable velocities) on Day 1 correlated directly with the number of corpora lutea (CL; r=0.92, P=0.0002) and of viable embryos (r=0.77, P=0.01). Correlations were also recorded between the number of HVPs on Day 3 and the recovery rate (r=-0.69, P=0.03), viability rate (r=-0.64, P=0.05), and percentage of degenerated embryos (r=0.65, P=0.04). The percentage of HVPs relative to the total area of ovarian cross section on Day 1 was correlated with the number of CL (r=0.95, P<0.001) and of viable embryos (r=0.85, P=0.002). This parameter on Day 3 was also correlated with the recovery rate (r=-0.69, P=0.03). The percentage of HVPs relative to the total Doppler area on Day 0 was correlated with the recovery rate (r=0.72, P=0.02). It can be concluded that sonographic assessment of high-velocity antral follicular blood flow has the makings of a useful non-invasive method to predict the outcome of the superovulatory treatment in ewes.

Early luteal development in Santa Inês ewes superovulated with reduced doses of porcine follicle‐stimulating hormone

“…Sanchez‐Dávila et al () reported similar number of CLs in response to 145 and 215 mg of total dose of pFSH for superovulation in goats whereas lower ovarian response was recorded when 80 mg was used; the same was recorded to produce transferable embryos. The number of CLs observed in this experiment was greater than observed by Oliveira et al () with the same protocol of superovulation in Santa Inês ewes using 200 mg of total dose of pFSH. Therefore, the reduction of total dose of pFSH in relation to the commonly used in small ruminants (200–256 mg; Oliveira, ) points to be beneficial; however, there seems to be a limit to this reduction.…”

Investigating and Modelling an Engineered Millifluidic In Vitro Oocyte Maturation System Reproducing the Physiological Ovary Environment in the Sheep Model

“…The flow rate was temporally set at 450 μL/min for the time to quickly fill the circuit and then regulated to 50 or 100 μL/min, according to the experimental design. Flow rates were chosen based on previous studies in the sheep which reported that ovarian blood flow gradually decreases from the order of milliliters/min in the ovarian artery [ 51 , 52 ], to microliters/min in the capillary network around the developing follicles, varying in relation to various aspects such as the anatomical district and the ovarian cycle stage [ 53 , 54 ].…”

“…During its development, although not exposed directly, but through the mediation of theca and granulosa cells, the COC receives nutrients and oxygen supply by continuous diffusion from the microcapillary network that surrounds the follicle. Ovarian blood flow rates range from milliliters/minute (at ovarian arterial level) to microliters/minute (at follicular capillary beds of antral follicles) [ 51 , 52 , 53 , 54 ]. In a previous study, we found that millifluidic IVM (mIVM) improved oocyte mitochondrial membrane potential, intracellular ROS levels, and mitochondria/ROS colocalization, markers of healthy oocyte cytoplasmic maturation.…”

Luteal function in cyclic goats treated with human chorionic gonadotropin administered by intramuscular or intravaginal routes at the time of artificial insemination

“…The HVDA was regarded as an upper and lower quarter of the Doppler scale bar that corresponds to the velocity range of 0.04 to 0.08 m/s. All colour pixels were detected using the 'Count/size' tool and subsequently converted to SI units (Oliveira et al, 2017).…”