Honors Theses

Affiliation

College of Agriculture and Life Sciences, Biochemistry, Nutrition and Health Promotion

College

College of Agriculture and Life Sciences, College of Arts and Sciences

College

College of Agriculture and Life Sciences

Department

Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology| Department of Classical and Modern Languages and Literatures

Department

Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology

Degree

Bachelor of Science

Degree

Bachelor of Arts (B.A.)

Major

Biochemistry, Foreign Language

Document Type

Immediate Open Access

Abstract

Mass semen production for genetic conservation and large commercialization is considerably limited in the swine industry. Boar semen have specific features that prevent mid- and long-term preservation in cooling and freezing extenders, respectively. The success of long-term semen preservation in liquid nitrogen following deep-freezing, also known as cryopreservation, is drastically limited in swine farms. Meanwhile, the preservation of chilled extended boar semen has limitations due to the progressive decrease of sperm fertility potential during storage. With the ultimate goal of producing high quality semen for larger distribution, there is a need to investigate novel approaches to improve boar semen quality, especially during chilled storage. This study is composed of three sets of experiments. Firstly, we processed extended boar semen in the laboratory to determine the ideal condition for handling spermatozoa in the following experiments. Secondly, we took advantage of the high brightness, photostability, and bio-conjugation capabilities of quantum dot nanoparticles (QD) to investigate sperm features through non-invasive molecular-based fluorescence imaging. The QD were conjugated with two low-abundant and small polypeptide hormones, arginine vasotocin (AVT) and gonadotropin-releasing hormone (GnRH). Fluorescence detection of both AVT and GnRH membrane receptors was enabled by conjugated QD-AVT and QD-GnRH binding to freshly harvested boar spermatozoa, followed by fluorescence imaging of labeled spermatozoa. The effects of QD-AVT and QD-GnRH binding on sperm motility and morphology characteristics were assessed with the Computer-Assisted Sperm Analyzer (CASA). The findings suggested the presence of AVT and GnRH receptors on boar spermatozoa, and the sperm labeling with QD conjugates did not significantly affect the motility or morphology characteristics. Thirdly, we studied the Gum Arabic (GA) phytochemical, a biopolymer extracted from the Acacia tree, which is used for various purposes in bio-industries. Various concentrations of GA were added to semen in commercial extender and the mixtures were stored for up to 7 days at ~18oC. Sperm quality parameters were analyzed at different time points during storage. Overall, spermatozoa stored with 25µg of GA exhibited higher motility, progressivity, and normal morphology compared to the control, without any GA supplementation. The results of this experiment indicate that non-invasive bioimaging through nanoparticle conjugates could be an effective way to improve the current understanding of sperm biology and mammalian reproductive processes. Furthermore, the use of the GA biopolymer shows great promise in maintaining and improving sperm quality during chilled storage.

Date Defended

11-1-2020

Thesis Director

Feugang, Jean

Second Committee Member

Hoffman, Federico

Third Committee Member

Oppenheimer, Seth

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