Repository logo

Browsing by Author "McCue, Patrick, committee member"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Development of a bison-specific embryo culture system through targeted supplementation of media with stage-specific growth factors
    (Colorado State University. Libraries, 2024) Acevedo Barriga, Carolina, author; Barfield, Jennifer P., advisor; Dawit, Tesfaye, committee member; Pinedo, Pablo, committee member; McCue, Patrick, committee member; Yuan, Ye, committee member
    In vitro embryo production (IVP) offers a practical genetic exchange method for bison herds, eliminating the need for live animal transport and reducing stress on the animals. While successful in cattle, IVP efficiency is lower in bison. This study aims to enhance bison embryo quantity and quality by supplementing IVP media with stage-specific growth factors. Thirteen growth factor receptors (GFRs) were screened in bison and bovine embryos, with six GFRs falling within acceptable ranges. Abattoir-sourced oocytes were used for IVP (4 replicates). GFR expression, notably IGFR2, BMPR2, FGFR1, and EGFR1, peaked in bison embryos at the zygote and 8-16 cell stages, with higher IL6 expression at the morula stage. Bovine embryos displayed highest expression of BMPR2, EGFR, and IGFR1 at zygote and 8-16 cell stages, and of FGFR1 and IGFR2 at zygote stages. Corresponding growth factors were incorporated into bison culture media based on GFR expression. Treatment evaluations, included EGF, IGF1, IGF2, IL6, BMP2, FGF1, and a combination of all GFs to bison culture media. Results revealed that the addition of BMP2 resulted in a decrease in cleavage rates. Notably, EGF, IGF1, and IGF2 enhanced blastocyst rates, with IGF1 significantly higher than the control. Subjective embryo qualitative evaluation showed an upward trend in the number of high quality expanded blastocysts, and lipid content decreased (IGF1) while cell count increased (IGF1, IL6, BMP2, FGF1) with growth factor supplementation. In conclusion, supplementing IVP media with GFs, particularly IGF1 at 50 ng/mL, significantly improved both quantity and quality of bison embryos. Application of IVP theology has advance the use of assisted reproductive technologies for bison, potentially benefiting other species.
  • Thumbnail Image
    ItemOpen Access
    Development of a direct (non-extracted) enzyme immunoassay for measurement of serum progesterone levels in mares
    (Colorado State University. Libraries, 2010) Brooks, Ryan Michael, author; Denniston, David, advisor; Bruemmer, Jason, committee member; Nett, Torrance, committee member; McCue, Patrick, committee member
    Progesterone (P4) is a steroid hormone produced by the corpus luteum of the ovary and the placenta of the mare. Progesterone is required for the maintenance of pregnancy and an assessment of endogenous concentration would be useful in many diagnostic applications related to equine breeding management. The overall objective of this study was to develop and validate a direct enzyme-linked immunosorbent assay (ELISA) for the measurement of P4 in serum of in the mare. The specific aims were as follows: 1) to develop a quantitative and sensitive progesterone assay that could be used for non-extracted equine serum or plasma, and 2) to convert the ELISA from a 96-well plate format to a single cuvette system to allow quantification by a commercially available spectrophotometer. Significant events in the successful development of the ELISA included the use of purified anti-progesterone antibody, heterologous combination of antibody and conjugate, use of TMB substrate, and methodology to avoid organic solvent extraction. It was determined that by lowering the volume of serum used in the assay and lowering the pH of the serum, the need for extraction could be avoided. The overall correlation between ELISA of non-extracted serum and radioimmunoassay (RIA) of extracted serum was high (r = 0.81); and the correlation between ELISA and RIA for progesterone concentrations less than 5.0 ng/ml, the range most important for clinical diagnosis, was even greater (r = 0.91). The direct ELISA assay has great potential for use in the equine breeding industry as it will allow for diagnostic tests to determine the adequacy of corpus luteum function in a pregnant mare, presence or absence of luteal tissue, and assessment of the end of seasonal transition.