Effects of Extra-Long-Acting Recombinant Bovine FSH (bscrFSH) on Cattle Superovulation

Abstract

Over the last few years, several commercial FSH products have been developed for cattle superovulation (SOV) purposes in Multiple Ovulation and Embryo Transfer (MOET) programs. The SOV response is highly variable among individuals and remains one of the main limiting factors in obtaining a profitable number of transferable embryos. In this study, follicle stimulating hormone (FSH) from different origins was included in two SOV protocols, (a) FSH from purified pig pituitary extract (NIH-FSH-p; two doses/day, 12 h apart, four consecutive days); and (b) extra-long-acting bovine recombinant FSH (bscrFSH; a single dose/day, four consecutive days), to test the effects of bscrFSH on the ovarian response, hormone profile levels, in vivo embryo production and the pluripotency gene expression of the obtained embryos. A total of 68 healthy primiparous red Angus cows (Bos taurus) were randomly distributed into two experimental groups (n = 34 each). Blood sample collection for progesterone (P4) and cortisol (C) level determination was performed together with ultrasonographic assessment for ovarian size, follicles (FL) and corpora lutea (CL) quantification in each SOV protocol (Day 0, 4, 8, and 15). Moreover, FSH profiles were monitorised throughout both protocols (Day 0, 4, 5, 6, 7, 8, 9, 10, and 15). In vivo embryo quantity and quality (total structures, morulae, blastocysts, viable, degenerated and blocked embryos) were recorded in each SOV protocol. Finally, embryo quality in both protocols was assessed by the analysis of the expression level of crucial genes for early embryo development (OCT4, IFNt, CDX2, BCL2, and BAX). P4 and cortisol concentration peaks in both SOV protocols were obtained on Day 15 and Day 8, respectively, which were statistically different compared to the other time-points (p < 0.05). Ovarian dimensions increased from Day 0 to Day 15 irrespective of the SOV protocol considered (p < 0.05). Significant changes in CL number were observed over time till Day 15 irrespective of the SOV protocol applied (p < 0.05), being non- significantly different between SOV protocols within each time-point (p > 0.05). The number of CL was higher on Day 15 in the bscrFSH group compared to the NIH-FSH-p group (p < 0.05). The number of embryonic structures recovered was higher in the bscrFSH group (p = 0.025), probably as a result of a tendency towards a greater number of follicles developed compared to the NIH-FSH-p group. IFNt and BAX were overexpressed in embryos from the bscrFSH group (p < 0.05), with a fold change of 16 and 1.3, respectively. However, no statistical differences were detected regarding the OCT4, CDX2, BCL2, and BCL2/BAX expression ratio (p > 0.05). In conclusion, including bscrFSH in SOV protocols could be an important alternative by reducing the number of applications and offering an improved ovarian response together with better embryo quality and superior performance in embryo production compared to NIH-FSH-p SOV protocols.

Towards Improving the Outcomes of Multiple Ovulation and Embryo Transfer in Sheep, with Particular Focus on Donor Superovulation

“…Likewise, in vivo embryo production using standard pig pituitary-derived FSH via eight injections (two injections per day) was compared against the application of the extra-long-acting single-chain bovine follicle-stimulating hormone (single injection for four days) for superovulation. The number of viable embryos were 6.32 ± 0.56 vs. 6.32 ± 0.56 ( p < 0.05) for the standard pig pituitary-derived FSH and the extra-long-acting single-chain bovine follicle-stimulating hormone, respectively [ 128 ].…”

“…The application of a medium-acting bovine follicle-stimulating hormone with a prolonged half-life could improve the substantially the results regarding the ovarian superovulation response and the embryo quality/yield. In conclusion, the use of bovine single-chain recombinant follicle-stimulating hormone in superovulatory treatments could be an important alternative, by reducing the number of applications and offering an improved ovarian response, together with improved embryo yield and quality and superior embryo production compared to conventional FSH superovulation protocols [ 128 ].…”

Expression and functional characterization of chimeric recombinant bovine follicle‐stimulating hormone produced in Leishmania tarentolae

“…Applying this approach, an almost identical chimera of single chain bovine FSH (scbFSH) was engineered and successfully expressed in CHO cells (AspenBio Pharma, named Venaxis, Inc. since 2012; patent: (Colgin, 2008)). Recently, recombinant single chain ovine (roFSH) and bovine (bscrFSH) FSH with long-lasting stimulating activity due to the incorporation of new N-glycosylation sites in the protein sequence were successfully applied to sheep and cattle (Gutiérrez-Reinoso et al, 2022;Sanderson & Martinez, 2020). The recombinant hormones induced superovulation at similar levels to conventional treatments but with fewer injections.…”

“…In the veterinary field, the availability of a rFSH offering consistent physiological results at affordable costs is of utmost relevance for proper livestock reproductive management (Baruselli et al., 2023 ; Gutiérrez‐Reinoso et al., 2022 ; Sanderson & Martinez, 2020 ). Here, we addressed this need by expressing and characterizing a single chain β‐CTP‐α chimera of bovine FSH (scbFSH) in L. tarentolae .…”

Genotyping of cows by LHCGR, FSHR loci and determination of the level of ovulation depending on the expression of the studied genes

“…A gene polymorphism is a difference in the DNA sequence (mutant and normal) in the genome of representatives of the same species. Single-nucleotide polymorphism is the difference of a single nucleotide in alternative genes ( Sharifiyazdi et al ., 2018 ; Guo et al ., 2021 ; Gutiérrez-Reinoso et al ., 2022 ).…”