Left unchecked and untreated, heat stress1 can cause wholesale declines in weight gain and feed efficiency in growing pigs, leading to costly economic losses for producers. In tandem with the right herd management, a combination of the two key compounds in ButiPEARL™ Z — butyric acid and zinc — can help pigs better stave off the harmful effects of heat stress, enabling them to absorb nutrients efficiently and achieve maximum potential rate of gain without growth depression.
What happens when heat stress occurs
When a pig experiences heat stress, a complex chain of events unfolds in which its different organ systems work to offset the harmful effects of that stress. In the process, those defenses sometimes unintentionally damage the body’s own tissues, at which point systems like the digestive tract start to incur damage. For example, when animals are experiencing heat stress, blood gets diverted to the skin to cool them off – causing damage to the intestinal villi and epithelia and breaking down the tight junctions through reduced blood flow and oxygen supply.
When heat stress occurs, microbes and toxic compounds in the intestinal lumen can break through the damaged protective layers in the digestive tract and infiltrate the gut, causing inflammation that makes it even more difficult for pigs to consume and absorb nutrients from feed. Ultimately, the animal loses the ability to maintain and increase its weight, a costly outcome for the producer who’s depending on a benchmarked rate of gain to meet production and revenue goals.
Lipopolysaccharide2 (LPS) — a bacterial component — is one of the major molecules attributed to the development of gut health problems associated with heat stress. When an animal experiences stress, cortisol — a stress hormone — is released as a protective response. In pigs experiencing heat stress, cortisol is released into the gastrointestinal (GI) system, which results in the secretion of inflammatory cytokines. This secretion causes the tight junctions between epithelial cells to loosen, allowing even more LPS and bacteria to infiltrate the digestive tract. Once this inflammatory reaction starts, the animal begins to show digestive symptoms, causing it to eat less and lose some ability to absorb nutrients from any feed consumed.
This chain of events is typically set in motion when pigs experience environmental temperatures around 85 degrees Fahrenheit and above, but temperatures in the mid-70s can be enough to cause weight gain to slow. Water consumption can also contribute to feed inefficiency during times of heat stress; animals will sometimes drink more water when experiencing heat stress or during cooler nighttime temperatures on a hot day, which can fill the stomach and make it difficult to consume feed.
Conditions that favor heat stress
Just as the ambient temperature has the potential to induce heat stress, so can a rapid increase in temperature that catches pigs’ bodies off guard and doesn’t allow them to adjust. With a gradual increase in temperature, animals’ bodies have time to adjust, whereas, sudden increases can cause heat stress even if temperatures aren’t near 85 degrees. Temperature fluctuations also have the potential to make animals experience heat stress. With unpredictable weather patterns like those in the last few years, heat stress is even more common.
“Pigs are very resilient animals; but, if temperatures rise too quickly, they’re going to feel a significant impact,” said Kemin Technical Services Manager Venkatesh Mani. “Under heat stress, you will see the challenge of animals not getting nutrients from their feed, as their GI system will not be working as efficiently as possible.”
Just how much damage an animal incurs under heat stress depends on age, duration of the stress, the resulting quantity of LPS and other inflammatory molecules absorbed, the health of the animal before the stress began, and the conditions in which the animal lives. Many of today’s pigs live in barns and facilities that are much cleaner compared to generations past, when animals were raised outdoors and on pasture. The cleanliness — and resulting lack of exposure to common potential inflammatory compounds — makes today’s pigs less able to manage an influx of potentially harmful bacteria caused by heat stress.
How butyric acid and zinc take on heat stress
While butyric acid3 and zinc have distinctly different functions when it comes to staving off the damaging effects of heat stress, the two make up an effective one-two punch when combined in ButiPEARL Z. Butyric acid is focused on the epithelial tissue itself, in addition to providing a multitude of other benefits systemically. It serves as an energy source for the tissue that prevents bacteria from being absorbed through digestion, which ultimately causes inflammation and resulting declines in weight gain in affected animals. Butyric acid can also act on immune cells and make them active. When foreign molecules do enter the body when it’s under stress, butyric acid helps prevent them from inflicting damage via absorption through loosened tight junctions.
“Butyric acid latches onto foreign organisms and kind of plays a pacifying role through a multitude of functions. By controlling the bacteria so they do not interact with epithelial tissue, potentially 10 tight junctions will be damaged instead of 100,” Mani said. “It can serve as an antimicrobial and kill pathogenic microbes, ultimately lowering the chances of an animal becoming infected by pathogens it absorbs during heat stress.”
Zinc, an essential mineral, is a component of more than 300 enzymes in the body. It helps maintain and restore the tight junctions in the epithelial tissue lining the GI tract, thereby preventing toxins from entering the digestive system and causing inflammation that leads animals to stop eating and experience poor feed performance. Zinc is also important to the body’s ability to produce T cells — key adaptive immune system components that act against invading pathogens. Additionally, zinc can play other defense roles, particularly under stress conditions.
“Tight junctions are made up of multiple proteins, and zinc is important in how it facilitates the production and maintenance of those tight junction proteins,” Mani said. “Zinc supplementation is especially helpful during heat stress when those tight junctions would otherwise become compromised. It’s important to maintaining the critical barriers of epithelial cells.”
These two key compounds are complementary to the general desired result of ButiPEARL Z4 — minimizing the harmful effects of heat stress — but they attack the problem from different angles.
“The functions are different but interconnected,” Mani explains. “Zinc is going to protect the intercellular tight junctions, and cells will wind up being healthier. That way, they’re more likely to absorb butyric acid and become even healthier. They don’t act in a sequential manner.
“It’s just like an athlete eating a healthy diet so he or she can practice more: Is it the food or the practice that makes him or her better? They’re both equally important. That’s what ButiPEARL Z does: It delivers two molecules important to intestinal health, making them available to GI cells simultaneously to deliver the greatest benefit.”
Delivering compounds where they need to go
Controlling the release of key ingredients can sometimes be a challenge with feed additives like ButiPEARL Z. That’s why it is encapsulated in MicroPEARLS® that help make those ingredients available to the right tissues in the digestive tract. Without encapsulation, key ingredients would be absorbed immediately upon entering the digestive tract instead of being made available to the lower portions of the gut, where they’re needed most.
The pearls are a combination of fats, oils and other proprietary molecules that help deliver ingredients consistently throughout the gut. The encapsulation slowly dissolves when the pearls transit through the intestinal tract, gradually allowing key ingredients to escape through pores on each pearl’s surface. This method of delivery sharply increases the efficacy of ButiPEARL Z in staving off the negative effects of heat stress on gut health by distributing the product throughout the tract.
“If you give butyric acid without encapsulation, it will go into the gastrointestinal tract and immediately be absorbed, then either used or expelled immediatelyin feces or urine,” Mani adds. “Encapsulating it releases the product continuously through the entire intestine. Our chemists have found encapsulation methods that will enable the product to be released in the small intestine, then more once it gets into the cecum and colon, where almost everything will be released. Very little releases early on. The product goes to the places where it is supposed to function in sufficient quantities.”
Encapsulating zinc in MicroPEARLS also has a herd management benefit. When encapsulated, a producer or nutritionist knows the specific source of the zinc when there may be other zinc sources in a specific feed ration. That information is helpful in determining the efficacy of the encapsulated zinc, and in accurately administering the product in the future.
Management considerations for heat stress and ButiPEARL Z
It’s impossible for producers to eliminate stress on their livestock completely. Even the act of consuming feed causes slight increases in stress hormones. Minimizing stress — like that from heat — and its negative effects on gut health is possible through the right combination of management and products, such as ButiPEARL Z. The two must be present simultaneously to ensure animals are healthy and productive.
“Management is very important; producers need to provide sufficient shelter, make sure their barns don’t get too hot, and make sure pigs have access to cold water in times when heat stress is likely. If those conditions are met, we can decrease the stress on the animals, especially when we administer ButiPEARL Z. This product alone is not going to solve all of your heat stress problems. Even under perfect conditions, animals are always going to be under some stress,” Mani said. anima
“It’s just like car insurance: You can insure your car and be protected, but you still have to drive carefully so you don’t damage your car and don’t hurt yourself. If you manage your pigs well, which most producers do, you will see the benefits of this product — ultimately, sustaining healthier animals and maximizing productivity in the face of heat stress.”
© Kemin Industries, Inc. and its group of companies 2019. All rights reserved.
- Schieck, S. Heat stress in swine affects production. University of Minnesota Extension. extension.umn.edu/swine-production-management/heat-stress-swine-affects-production
- Norimatsu, M., T. Ono, A. Aoki, K. Ohishi, T. Takahashi, G. Watanabe, K. Taya, S. Sasamoto, and Y. Tamura. 1995. Lipopolysaccharide-induced apoptosis in swine lymphocytes in vivo. Infection and Immunity. 63(2):1122-1126.
- Gourley, K. M., J. C. Woodworth, J. M. DeRouchey, M. D. Tokach, R. D. Goodband, and S. S. Dritz. 2016. Comparing the effects of butyric acid source and level on growth performance of nursery pigs. Kansas Agricultural Experiment Station Research Reports. 2(8).
- ButiPEARL™ — Encapsulated butyric acid for a healthy swine and poultry gut. Kemin Industries. Kemin.com/na/en-us/products/ButiPEARL