Good for the gut and the planet: Ruminant professor searches for key to improve cattle digestion, reduce greenhouse gases

In the lab of ruminant nutrition professor Uchenna Anele, Ph.D. lies a quest to find the “fish with the golden coin” –  the essential oil or oils that can improve digestion and reduce greenhouse gases in cattle.

Through batch culture studies, simulated rumen techniques and “big data” analysis, Anele and his students are on the hunt for the best essential oils and plant nutraceuticals that will cut down on methane emissions in cattle and improve the animal’s gut health during digestion.

“A healthy gut is a healthy animal, and a healthy animal is a productive animal,” said Anele. “The farmers that we are interested in helping with our research are small, limited resource and disadvantaged farmers. We would like to commercialize our results and we’re looking at inputs that will not be so expensive.”

In 2017, Food and Drug Administration policies restricted the use of antibiotics in growth production for food animals, specifically to facilitate the increase of an animal’s rate of weight gain and feed efficiency.

“Before then, we had been using antibiotics at sub-therapeutic levels to improve animal performance,” said Anele. “That was phased out. From there on, we looked at how we could continue improving gut health without using antibiotics. That led to using regenerative plant nutraceuticals.”

Nutraceuticals, defined by the U.S. Food and Drug Administration as any substance that is a food, or part of a food, that has medical or health benefits, can be single nutrients, like Vitamin C, that help prevent or treat disease. Unlike pharmaceutical supplements, which are usually pills or tablets that contain an isolated nutrient, nutraceutical supplements are nutritionally-rich whole foods.

Green tea, cod liver oil, Echinacea and ginseng, for example, are all nutraceuticals.

Anele’s Evans-Allen funded project, begun in 2020, aims to utilize plant nutraceuticals – the parts of the plant that has medical or health benefits – in a multidisciplinary approach that farmers can use to maintain a healthy gut in their ruminant livestock.

“The plant nutraceuticals have medicinal value,” said Anele. “But they also don’t have a broad spectrum of action as antibiotics. They have limitations, but we know that there’s something there. So, locating the right nutraceuticals is like finding the needle in the haystack. It is there; we just have to pinpoint it.”

Research laboratory technician Lydia Olagunju, Ph.D., doctoral student Joel Alabi, and Anele with the lab’s RUSITEC, a device that replicates the cattle’s digestive habits.

At the same time, Anele knows that the industry needed ways to reduce ruminants’ methane emissions during feeding. And so, his research is looking into that aspect of the ruminant-feed issue as well, by searching for the perfect, plant-based food additive that will both maintain an animal’s gut health and control its methane emissions.

“My research is also focused on reducing greenhouse gases from a producer’s perspective,” said Anele. “Up to 12 percent of the total gross energy (the amount of energy in animal feed) given to the ruminants and the livestock can be lost as methane. That’s a significant loss from a producer’s perspective, because that energy and those nutritional benefits are lost, and the producer spends more money feeding the animal.”

In addition, Anele said, the methane emission from the animal is an environmental issue; as a greenhouse gas, its presence is more than 25 percent more potent than carbon dioxide at trapping heat in the atmosphere, affecting the earth’s temperature and climate system, according to the Environmental Protection Agency.

The study begins with a batch culture, a closed culture system that contains limited amounts of nutrients, which screens numerous plant nutraceuticals, medicinal plants, essential oils, and prebiotics.

“We have three orbital shakers in a reach-in incubator,” said Anele. “Each orbital shaker can contain up to 88 serum bottles. If we pack it very well, it can contain 250 bottles and each bottle represents an animal. This setup has helped us to evaluate thousands of samples. It’s like mimicking what goes on inside the ruminant. That is always the first step in our screening process, because you don’t know which one will give you the best results. Instead of using a hook, we use a net, because you don’t know which fish has the golden coin.”

The batch culture study alone, Anele said, has been so extensive that he has graduated three master’s degree students in the process.

After samples have been screened, a handful are selected and tested to see if they can reduce greenhouse gas emissions without affecting the animal’s ability to digest dry matter and, as an incentive, if they can increase total volatile fatty acids and microbial mass.

At N.C. A&T’s University Farm, Anele and his students collect samples from six cattle each week.

“We repeat these and move on to the second stage of the study, but often repeat the batch culture to make sure we are consistent,” said Anele.

That second stage, for the samples selected and tested, involves replicating the animal’s digestive system through RUSITEC, or “rumen simulation technique.” In Anele’s lab, he and his students run samples through a device that mimics the cattle’s feeding and digestive habits, and collects gaseous material in a gas bag.

Anele prepares to collect dry matter samples from the rumen of that week’s cattle at the University Farm.

“The gas bag demonstrates the way the animals expel gases,” Anele said. “The digested material is then collected. You have a container that has artificial saliva, simulating the production of saliva in animals, and it’s being infused into 1-liter vessels, representing the rumen of the animals and breaking down the feed.”

Through this process, Anele and his students can look at the products used from the initial batch culture and, by comparison, analyze their effects on breaking down dry matter.

“Are the oils and nutraceuticals reducing greenhouse gases? By how much? Are the animals producing a lot of microbial mass? Are the products increasing the amount of total volatile fatty acids? These are some of the major variables that happen in the live animal,” Anele said. “Ruminants, when they eat anything, produce volatile fatty acids and microbial mass in the rumen, the more volatile fatty acids and microbial mass are produced, the better, which means less gas that the animal will pass into the environment. That gives us the idea of the project we are doing.”

A major component of Anele’s research is “big data” and how the results and information from the batch culture and RUSITEC studies could provide long-term benefits outside the scope of this project. For example, this project is primarily focused on beef and dairy cattle, but with further study, the same results can be potentially used to help the digestion of smaller ruminants, like sheep and goats.

“What are the products like when digested?” said Anele. “Metabolites check everything produced from amino acids. We generate tons of data that we could analyze.”

The research has yielded results that can potentially reduce greenhouse gases, Anele said, but the project is ongoing.

“I’m not satisfied yet,” said Anele. “We are trying to optimize the right nutraceuticals that will reduce greenhouse gases without affecting dry-matter digestibility. Even if the product doesn’t significantly improve dry-matter digestibility, if it doesn’t negatively affect it, that’s a win.”