Aggie-feed: Utah State University researchers introduce healthier alternative to antibiotics in livestock production

LOGAN, Utah, USA — Humans and farm animals share a common affliction: Inflammation.

“Inflammation, wherever it occurs in your body, is your immune system’s response to a host of factors, including injury or infection,” says Utah State University chemist Cheng-Wei “Tom” Chang. “It may be minor and temporary, but chronic inflammation can lead to serious conditions, including cardiovascular disease, arthritis, cancer, Alzheimer’s disease, diabetes, osteoporosis, Parkinson’s disease, hepatitis, autoimmune disorders and inflammatory bowel disease.”

The last disorder on that lengthy list — known as IBD — is a modern-day scourge in livestock, Chang says, which is often caused by infection from harmful microbes or exposure to chemicals, including antibiotics.

Antibiotic usage in livestock, introduced in the early 20th century, was meant to promote animal health, says biologist Jon Takemoto, Chang’s USU research partner.

“Antibiotics have been widely used to stave off bacterial infections that plague livestock — especially in large, commercially run animal production facilities,” says Takemoto, professor emeritus in USU’s Department of Biology. “In addition, they’ve enabled farmers to produce larger, more profitable animals more quickly.”

But antibiotic usage, he says, in addition to fostering antibiotic resistance, often results in serious side effects in individual animals, including IBD. The malady lowers production and can cause death, especially in young animals.

“Antibiotics ushered in revolutionary impacts not only on human health but also on food production as farmers and ranchers turned to the miracle drugs to increase livestock growth and survival,” Takemoto says. “But escalating antibiotic resistance poses ominous challenges to both livestock and human health, including the ability to fight off risky superbugs, as public managers seek interventions.”

In April 2025, the U.S. National Institutes of Health reported antibiotic usage in animal husbandry accounts for more than 70 percent of worldwide usage. The United Nations Food and Agriculture Organization expects that percentage to rise significantly by 2030 unless livestock-producing countries pledge reductions.

Takemoto and Chang, in collaboration with Yuan-Yu Lin of National Taiwan University, report a natural alternative rising from the long-known, anti-inflammatory substance biliverdin, which could promote better gastrointestinal health in livestock while reducing reliance on antibiotics. In a study conducted with Ching-An Peng of the University of Idaho, the USU scientists note biliverdin also reverses the effects of osteoporosis in a mouse model. Takemoto, Chang and Lin shared additional findings in a review paper in the March 19 issue of the open access journal Molecules.

“Biliverdin, produced by plants and animals, is a potent antioxidant and anti-inflammatory that protects against oxidative stress and injury,” Takemoto says. “We propose a natural analog to biliverdin, known as mesobiliverdin, which bypasses the widespread need for antibiotics in livestock production and enables commercial-scale production of the natural substance.”

Chang, professor in USU’s Department of Chemistry and Biochemistry, says previous attempts over many years to produce large quantities of biliverdin for medical use as pharmaceuticals have failed.

“Availability of biliverdin is limited and is often plagued by uncertain purity,” he says. “We have developed a way to produce our biliverdin analog, mesobiliverdin IXα, in pure, large quantities from microalgae.”

Chang reports mesobiliverdin IXα, as the researchers predicted, behaves like biliverdin in all the ways the team has tested it.

“While learning to purify mesobiliverdin IXα, we had the idea of making the product ‘Aggie-Feed,’” he says. “Mesobiliverdin-enriched microalgae offers a cost-effective method of providing safer, nutritional sustenance for livestock.”

Microalgae is abundant and commercially scalable, he says.

“We can produce mesobiliverdin-enriched microalgae for livestock feed without additional purification steps that made previous production efforts too costly and ineffective,” Chang says. “Aggie-Feed is a ready-for-market supplement beneficial for animal health.”

Takemoto says interest in biliverdin research is re-emerging due to its potential as a therapeutic agent for humans.

“Harvard Medical School immunobiologist Fritz Bach, who died in 2011, pioneered the study of biliverdin, which is a greenish pigment derived from red blood cell breakdown,” Takemoto says. “Bach was seeking solutions to obstacles in transplant immunology, including organ donation rejection.”

Until that time, biliverdin, which in animals is converted to bilirubin, transported to the liver and excreted, was considered a waste product, he says.

“Excess biliverdin and bilirubin in humans can cause jaundice, which is often an indication of an underlying health problem,” Takemoto says. “Instead, from Bach’s work and insight, we’re learning of the benefits of biliverdin, which protects against cellular damage and disease. If he were alive today, Professor Bach would certainly understand and appreciate our Aggie-Feed.”