An Iowa State professor and his laboratory are aiming to understand the biological factors affecting male fertility with a primary focus on pig and bovine reproduction.
Despite having sperm with good motility (forward movement) and morphology (cell shape), one out of every four boars experiences a conception rate of less than 80%.
The issue mirrors human fertility challenges, where one out of eight couples struggle with infertility and one-third of those cases are attributed to male factors, according to the National Institute of Health.
Karl Kerns, assistant professor of animal science, and his laboratory have various state-of-the-art tools and equipment across their andrology, molecular biology and in-vitro fertilization (IVF) labs.
The IVF labs range from computer-assisted semen analysis and time-lapse fluorescent microscopes to image-based flow cytometry paired with deep learning, artificial intelligence analysis methods and sorting flow cytometry.
Kerns’ lab dedicates most of its efforts to pigs and cattle.
“Pigs and cattle are species we have plenty of oocytes and sperm cells available for, allowing us to conduct in vitro fertilization research,” Kerns said. “They also are effective models for human reproduction compared to rodents, who do not model the human as well genetically or phenotypically at the cellular level.”
The lab also extends the research to other species, including stallions, canines, tigers and some small rodent models like mice.
The lab’s goal is to enhance reproductive efficiency by analyzing sperm quality and identifying biological markers that influence fertility rates.
The process involves sorting sperm cells using advanced flow cytometry technology. The sorter system uses microfluidics and lasers to analyze and sort cells based on fluorescence-marked biomarkers.
“We can track thousands of cells per second, identifying key fertility indicators and sorting them accordingly,” Kerns said.
The process allows for an in-depth analysis of fertility potential and production capabilities.
Kerns’ team employs both positive and negative biomarkers to evaluate sperm quality. Positive biomarkers are generally considered good and reflect increased chances of conception, while negative biomarkers can indicate compromised fertility potential.
The team also assesses mitochondrial activity, zinc signatures and protein detection, all of which assist the lab in detecting and analyzing both healthy and unhealthy sperm.
Ian Shofner, a third-year PhD student in mammalian reproductive physiology, focuses on artificial intelligence (AI) and developing models that predict sperm fertility metrics in the Kerns Lab.
“Currently, male fertility diagnostics are lacking in accuracy, and my work aims to improve these predictions for better assessments of male fertility in mammals,” Shofner said. “With this, we intend on enabling the industry to make cost-effective AI solutions for fertility diagnostics using affordable brightfield microscopy technology.”
Tyler Weide, a third-year PhD student in the interdepartmental genetics and genomics program, has an emphasis on uncovering the molecular and cellular mechanisms for fertilization.
“It’s an ideal environment for those interested in reproductive physiology to apply critical thinking in solving complex problems relevant to both agricultural and biomedical sciences,” Weide said.
Kerns’ research involves partnerships with institutions such as the University of Wisconsin-Madison, the USDA’s Agricultural Research Service in Beltsville, Maryland, and Fort Keogh, Montana.
Additional collaborations include the University of Missouri, the University of Georgia, the University of Illinois and the Omaha Zoo for studies on tiger reproduction.
Kerns advocates for increasing awareness and enthusiasm for science among young students, ensuring a strong pipeline of future researchers.
“Being an undergraduate student at Iowa State exposes you to a wide variety of fields,” Kerns said, encouraging students to take advantage of research opportunities and student organizations.
“My work in this lab strengthens technical skills, critical thinking and scientific communication,” Megan Johnson, a senior in animal science, said. “Which are essential traits for future careers in research, veterinary medicine and animal reproduction.”
With ongoing technological advancements and interdisciplinary collaborations, Kerns’ lab continues to push the field’s understanding of reproductive science, finding more efficient and effective fertility solutions.
“Working in Dr. Kerns’ Lab provides invaluable opportunities to address real-world challenges in the agricultural community by using advanced reproductive technologies,” Lindsey Jennett, an undergraduate senior in animal science, said.
