202 Effects of administration of mycobacterium cell wall fraction during follicle superstimulation on oocyte numbers and embryo development following ovum pickup and in vitro embryo production in virgin dairy heifers
W. Brown A , M. Oliveria B , R. Reis Silva C , D. Demetrio B and J. Block AA Department of Animal Science, University of Wyoming, Laramie, WY, USA
B RuAnn Genetics, Riverdale, CA, USA
C Federal University of Goias, EVZ, Golania, CO, Brazil
Reproduction, Fertility and Development 35(2) 230-230 https://doi.org/10.1071/RDv35n2Ab202
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Pro-inflammatory cytokines play an important role in certain reproductive events, such as ovulation and uterine receptivity. However, pro-inflammatory cytokines can be detrimental to reproductive processes if elevated in other contexts, such as in animals with endometritis. The objective of the present study was to determine whether induction of a pro-inflammatory response during follicle superstimulation could affect the efficacy of in vitro embryo production (IVP). The study was conducted at a commercial dairy in central California from March to July 2022. Ovum pickup (OPU) was performed on a weekly basis using a cohort (n = 4) of virgin, Holstein heifers (8–15 months old). Each cohort was submitted to two successive OPUs at 14-day intervals. Prior to each OPU, donors were submitted to a follicle superstimulation regimen that included administration of gonadotrophin-releasing hormone (GnRH; Fertagyl®, Merck Animal Health, 129 µg, IM) four days before OPU, followed by a single injection of follicle stimulating hormone (FSH; Folltropin®, Vetoquinol, 80 mg, IM) 36 h later. Then, OPU was performed 46–48 h after FSH administration. Prior to enrollment in the study, animals were randomly assigned in a 2 × 2 crossover design to receive either sterile saline (5 mL, IM) or mycobacterium cell wall fraction (MCWF; Amplimune®, NovaVive, 5 mL, IM). The treatment assigned for the first OPU was alternated to the opposite treatment for the second OPU such that all animals received both treatments. The assigned treatments were administered in conjunction with FSH dosing during the follicle superstimulation regimen. Following each round of OPU, recovered cumulus-oocyte complexes (COCs) were evaluated using IETS criteria (Annex 2, IETS Manual, 2021). Harvested COCs were then submitted to IVP (Ruann Genetics). For each donor, the same bull was used for in vitro fertilisation (IVF) for each OPU. Cleavage was assessed on Day 3 after IVF. At Day 7, embryo development was recorded, and the number of transferable embryos was determined using IETS classification criteria (stages 4 to 9 and grades 1 to 2). Data were analysed using mixed model analysis of variance. There was no effect of MCWF treatment on oocyte numbers or embryo development following OPU-IVP (Table 1). Results indicate that administration of MCWF during follicle superstimulation did not stimulate or inhibit the efficacy of IVP in virgin heifer donors.
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