“From fish to pigs”: The unexpected turns that led Li-Hsuan Chen to his PhD
When Li‑Hsuan Chen left Taiwan to begin his PhD in the Nutrition Pillar of PIG‑PARADIGM, he didn’t expect his research journey to shift from studying fish skin to examining pig gut health.
But as he prepares to graduate—his thesis built on four scientific articles, one already published—he reflects on a path full of surprises, challenges, and discoveries that reshaped his career.
“My background was actually fish. “During my master’s time, I studied the fish skin microbiome and how they interact with aquatic pathogens. I never imagined working with pigs—but the host–microbe interaction theme has always fascinated me.”
That curiosity carried him into PIG‑PARADIGM, where he spent three years investigating how dietary protein levels and surplus essential amino acids influence gut health in piglets. His key question was simple but important:
Can we reduce post‑weaning diarrhea—and ultimately antimicrobial use—by providing surplus essential amino acids?
“We knew from large‑scale studies from SEGES, a Danish company, that adding 35% surplus essential amino acids on top of a high‑protein diet could reduce diarrhea treatments by 50%,” he explains. “But we didn’t know why. So my project focused on uncovering the mechanism.”
To do that, Li‑Hsuan combined in vivo pig trials with in vitro cell models, including intestinal cell lines and organoids. “I had never worked with organoids before,” he says. “I even spent time in Barcelona learning the techniques. Without PIG‑PARADIGM, I would never have had that opportunity.”
His findings brought new clarity.
“We saw the same effect as the trials from SEGES—the surplus essential amino acids did reduce diarrhea,” he says. “And when we looked into the gut metabolome, we found changes in purine nucleotides and nucleosides. These compounds seemed to play a role in supporting gut health.”
To test this further, he mixed harmful protein‑fermentation metabolites with purine nucleosides and nucleotides in intestinal cell models. “Some of the harmful metabolites clearly damaged the cells,” he recalls. “But when we added the purine nucleosides and nucleotides, we saw they could actually soothe those negative effects.”
The results echo previous studies showing that purine nucleotide supplements can reduce post‑weaning diarrhea—suggesting they could become part of future feeding strategies. Still, Li‑Hsuan emphasizes that more work is needed.
“We need to test how much to add, how pigs respond, and what it means for growth performance,” he says. “But at least now we know the mechanisms are there. That’s a big step.”
Beyond the science, PIG‑PARADIGM shaped him in ways he didn’t expect.
“This project brought together so many techniques—metabolomics, cell lines, organoids—it’s expensive work. Without this funding, I could never have learned all of this,” he says. “I’m really grateful.”
He also loved the collaborative spirit. “At the meetings, we saw research from many angles—genetics, nutrition, microbiology. Everyone is trying to answer the same question: How do we reduce antimicrobials? That was inspiring.”
As he prepares to defend his thesis, Li‑Hsuan feels ready for what comes next.
“If changes in diet interventions can reduce diarrhea, we can reduce the need for antimicrobials. My research offers one piece of that puzzle,” he says. “And now it’s time for the next step—to take these mechanisms from research into real applications.”