Getting at the ‘guts’ of piglet health

Producers can review biosecurity, nutrition and animal husbandry practices to get their pigs off to a good start.

by Kate Ayers

A strong swine herd begins with good piglet gut health, says Dr. Ben Willing, an associate professor in the agricultural, life and environmental sciences department at the University of Alberta.

Indeed, “intestinal health is the foundation for systemic health in all animals,” he says.

“The impact of an imbalanced intestinal microbial population or reduced intestinal barrier function can result in systemic inflammation, changes in whole body metabolism and overall poor growth and disease susceptibility,” he explains to Better Pork.

Piglets are vulnerable during their early stages of development, as pathogens and stress can compromise their well-being. However, producers can create barn environments and feed protocols that minimize the challenges piglets face.

piglets eating
    National Pork Board and the Pork Checkoff, Des Moines, Iowa photo

This news story reviews the functions that the gut plays in maintaining overall pig health. Better Pork spoke with industry experts to learn how hog producers can protect piglet gut health.

Gut function

The gastrointestinal (GI) tract is a series of organs that play important roles in the general health of animals. The main organs are the tongue, esophagus, gut, small intestine, cecum and large intestine.

Other associated organs that are critical for GI function are the gall bladder and pancreas. Indeed, the GI tract is “the largest surface area where the pig is exposed to the outside world,” says Chad Stahl, the chair of animal and avian sciences at the University of Maryland.

The gut’s role extends beyond simply digesting and absorbing nutrients from food.

The GI tract, including the gut, also serves as an immune system powerhouse, protecting animals from a wide array of pathogens. The tract supports a dynamic environment where fermentation, enzyme secretion and pH conditions are in constant flux.

The tract is home to the largest number of immune cells in the animal’s body, Stahl says.

Dr. Greg Wideman, a veterinarian at South West Ontario Veterinary Services in Stratford, Ont., agrees that the gut is critical for proper immune function.

“Many of the bacteria, viruses and parasites that the pig will encounter in its life will” pass through the gut, he says. Gut microbes deter pathogenic bacteria, toxins and other compounds that could harm the animal.

piglets nursing
    National Pork Board and the Pork Checkoff, Des Moines, Iowa photo

A piglet’s physiology and environment can largely affect GI functionality. Such factors include digestion and absorption, GI tract microbiota, GI tract mucosa, diet, welfare and immune status, says a December 2017 article by Pietro Celi and others in the journal Animal Feed Science and Technology.

Microbiota and mucosa in the GI tract are essential to keep piglets healthy. Gut microbiota, which are comprised of trillions of cells, are important for nutrition and immunity. An organism’s body hosts these cells shortly after birth.

Intestinal mucosal cells create physical and chemical barriers between the potentially hostile environment in the lumen of the intestine and within the pig. These cells absorb nutrients, secrete waste and help trigger immune responses.

“Anything we can do to maintain the barrier function of that mucosa is going to improve piglet gut health and feed efficiency,” says Stahl.

“Improving the integrity of the intestinal mucosa – not just by reducing pathogens and toxins, but also by feeding the mucosa appropriately and reducing stressors that we know can challenge the gut health of a piglet” – is important.

A properly functioning GI tract ensures that piglets can grow and fight off diseases. Gut health is particularly important for newly weaned piglets, as the tract undergoes structural and functional changes during the post-weaning transition

to a nursery barn.

Indeed, the stress of weaning can cause the intestinal villi to shorten, reducing the piglets’ absorption capacity and feed efficiency, says a 2013 review paper by Joy Campbell and others in the Journal of Animal Science and Biotechnology. Villi are small finger-like projections that increase the surface area of the small intestine. They absorb nutrients.

External stressors

feeder pigs standing on floor
    National Pork Board and the Pork Checkoff, Des Moines, Iowa photo

Producers who limit the number of health and environmental challenges that young pigs encounter are more likely to maintain a healthy herd.

Stress is the main external factor that can jeopardize piglet gut health, says Willing.

Weaning, for example, can compromise the piglet’s intestinal environment. Because of emotional and dietary stresses, unhealthy microbiota can inhabit the gut.

The invasion of pathogenic bacteria and viruses can also pose problems for growing piglets.

“Some of the most common bacterial pathogens we see are the E. coli-caused diarrheas,” Stahl says.

Salmonellas and clostridial strains can also create issues. “And there are many viruses that can also cause intestinal problems,” he adds. The porcine reproductive and respiratory syndrome (PRRS) virus, for example, can compromise piglet gut health and development.

Contaminated feed, such as corn with mycotoxin, can lead to significant gut issues. Many producers in southwestern and western Ontario found high mycotoxin levels in their 2018-19 corn because of a wet and prolonged harvest season.

This toxin can “modulate the immunity of the animal and make the animal more susceptible to viral or bacterial infections,” says Martin Lessard, a research scientist with Agriculture and Agri-Food Canada at the Sherbrooke Research and Development Centre in Quebec.

In addition, hog producers who have nursery piglets at various weaning ages and weights may find health management tougher than the farmers who have piglets that are developing more uniformly.

In nurseries with scattered piglet weights, “it is more difficult to get the right temperature and feed in front of pigs,” Wideman says.

Lessard agrees.

“Animals that have a low birth weight could be more susceptible to infection after weaning,” he adds.

Optimum barn conditions

Although piglets are exposed to many stressors in the first few weeks of life, producers can follow a process in their barns to set the animals up for success.

Adhering to strict biosecurity practices can help pigs develop to their full potential, Stahl says.

Biosecurity is particularly important “around pig transport and entrance to the farm.” It prevents the spread of deadly diseases, Wideman adds.

“If we fail there, then we could introduce a virus or bacteria so virulent that the pigs just cannot survive,” he says.

Farrowing and nursery conditions are also vital.

As soon as a piglet is born, it “has to get dry, fast,” Wideman says.

Ambient temperature, can also put gut health at risk. For example, “the chilling of piglets in a farrowing crate or nursery can prevent those piglets from developing properly,” he says.

Keeping piglets warm is particularly critical in the winter.

Producers can also adjust their production windows to accommodate a later weaning age, which could help piglets make healthier transitions to nursery barns.

“One of the easiest things that can be done, and has the biggest impact, is to shift to an older weaning age,” Stahl says. Piglets should not be weaned prior to 21 days of age, he suggests.

“When piglets are weaned early, the stress that occurs around weaning is very damaging to the gut. … If you wean piglets at a younger age, the animal’s GI tract is not yet fully developed. So, weaning animals early can cause much greater damage, and that damage lasts for a much longer time.”

Piglets that are healthy post-weaning will perform better as adult pigs.

“One of the biggest determinants of how well a pig does ... is whether or not it had a healthy gut at the time of weaning,” Wideman says.

The best conditions “enable a piglet to eat and digest solid food, which is important.”

Nailing down nutrition

Piglets that receive the nutrients they require will be better prepared to fight off disease and infection.

And good nutrition begins within piglets’ first few hours of life. The animals’ timely consumption of colostrum plays an integral role in ensuring well-being and immunity development.

“Piglets develop their immune systems during the lactation period,” says Lessard.

piglets sleeping on floor next to sow
    National Pork Board and the Pork Checkoff, Des Moines, Iowa photo

“The colostrum and the milk contain several functional molecules including antimicrobial peptides, antibodies, and oligosaccharides, which contribute to a healthy digestive tract. Both colostrum and milk also contain a lot of growth factors and nutrients that are important for the maturation and integrity of intestinal mucosa development,” he explains.

Mothers transfer antibodies and several other immune factors to piglets through the colostrum and milk. This passive immunity contributes to the establishment of beneficial microbiota in piglets’ guts, which will foster healthy GI tracts, he adds.

The combination of these functional molecules promotes the development of healthy intestines and contributes to robust immune systems.

Introducing creep feed during the sow’s lactation period can help ensure that piglets remain healthy throughout and following weaning.

Farmers could try creep feeding piglets one week before and two weeks after weaning. Producers must provide “nutrients and feed supplements that will contribute to the development of the gut microbiota and immune system of the piglet” during this time frame, Lessard says.

“The maturation of the intestinal immunity takes at least six to seven weeks.”

So, the nutrition program from birth to the time after weaning, around six weeks of age, is particularly important for the maintenance of piglet GI tract health.

If they desire, producers can use bovine colostrum as a feed supplement for piglets.

“It is a good source of protein, and the milk’s molecules support the development of microbiota to maintain good bacteria and control the bad bacteria,” Lessard adds.

The colostrum also provides “peptides and other nutrients that will be useful for maintaining the integrity of the mucosa,” he says.

“Piglets fed colostrum may still get sick, but they can recover faster.”

New rules, same diligence

In December, Health Canada implemented new rules governing antimicrobials in livestock production. Canadian farmers require a prescription from a veterinarian to purchase items on the Prescription Drug List, including acetaminophen and penicillin.

bulk bin feeder nursery
    National Pork Board and the Pork Checkoff, Des Moines, Iowa photo

Some farmers are using nutraceuticals and functional foods as alternatives to antibiotics in their feed formulations for both piglets and sows.

“The sow’s health is a critical component in supporting piglet health,” says Willing.

“Feeding sows diets with fermentable fibre has been shown to improve the quality of milk, including the amount of antibodies they transfer to their piglets. This also allows sows to transfer healthier microbial populations to their piglets.”

Wideman agrees that a healthy piglet starts with a healthy sow.

sow drinking water
    National Pork Board and the Pork Checkoff, Des Moines, Iowa photo

“In the whole world of nutraceuticals and natural products, the one that I feel most confident about is acidified water for sows that have suckling piglets,” Wideman says.

“We’ll learn more about nutraceuticals and natural products as we go along.”

Farmers must choose wisely, as many products which are said to promote pig gut health have recently flooded the feed market.

“There has been a tremendous increase in a broad range of products that fall under the nutraceutical umbrella,” says Stahl.

“Some are direct nutrients that help feed the intestinal cells directly. Others are designed to help improve intestinal cell function … or work to select against bad bacteria and improve the number of good bacteria in the gut.”

Farmers should speak with their veterinarians to choose products that will work best for their operations and herd health goals.

Producers can share production strategies as they become accustomed to these regulatory changes.

For example, farmers can participate in the Ontario Pork Industry Council’s antimicrobial use benchmarking project, Wideman adds.

This project “puts farmers in the same room with one another” where they can discuss antibiotic use, he says. “They can learn from each other and review practices for disease control using fewer antibiotics.”

Researchers also continue to study ways to promote a healthy microbiome without using antimicrobials.

“We are looking to figure out what beneficial and protective microbes are missing from our pig populations and finding ways to reintroduce them while keeping pathogens out,” Willing says.

Indeed, maintaining piglet gut health requires a coordinated effort by a producer’s advisory team.

“The vet and nutritionist need to work together because sickness is often a combination of infection, environment and overall management – especially nutrition management – and everyone needs to work together to figure it out,” Wideman says.

Promoting healthy piglet gut development is vital to ensure overall hog herd health.

Although piglets sometimes face challenges that can make them more susceptible to disease, producers and industry professionals have strategies at their disposal to help piglets develop into resilient and productive hogs. BP

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