Swine Gut Health: Integrated Nutrition for Growth and Resilience

Why weaning remains a nutritional challenge

The period surrounding weaning places considerable pressure on young pigs. Their digestive and immune systems are still developing at the same time that they encounter major changes in diet, housing, social environment and microbial exposure.

Modern production adds further complexity. Larger litters associated with hyperprolific sow genetics can increase variation among piglets at birth, while efforts to move away from routine in-feed antibiotics and pharmacological zinc oxide have increased interest in alternative nutritional strategies.

As a result, maintaining performance after weaning increasingly requires attention to more than nutrient specifications alone. Digestive efficiency, microbial stability, epithelial integrity and immune competence all become part of the nutritional equation.

Start with digestion: getting more from the diet

One logical place to begin is nutrient digestion.

Several studies discussed in the Frontiers Research Topic examined enzyme-based strategies under demanding nutritional conditions, including reduced-protein formulations and diets containing high levels of soybean meal.

Interventions involving phytase, xylanase, carbohydrases and protease, used individually or in combination with acidifiers, were associated with better nutrient utilization and indicators of intestinal health.

The studies reported improvements in amino acid utilization, reductions in biomarkers associated with intestinal irritation and, under some experimental conditions, lower post-weaning diarrhea.

What happens after digestion matters too

The interaction between diet and hindgut fermentation represents another important piece of the puzzle.

Research summarized by the authors showed that branched-chain volatile fatty acids could influence microbial fermentation efficiency and nutrient utilization, particularly when pigs consumed high-fiber diets.

Another study investigated spray-dried plasma during the nursery period and reported a lower prevalence of severe post-weaning diarrhea.

Together, these findings illustrate why modern feed formulation is increasingly interested not only in what the animal digests, but also in how the remaining dietary substrates interact with the intestinal microbial ecosystem.

The microbiome is only one part of gut health

Microbiome modulation has become a major focus of animal nutrition research. However, simply changing the abundance of certain bacteria does not necessarily mean intestinal health or performance will improve.

Some of the studies highlighted in the Research Topic therefore examined microbial changes alongside epithelial integrity and host responses.

Galacto-oligosaccharides, for example, were associated with reduced adhesion and invasion by enterotoxigenic Escherichia coli (ETEC), while also preserving epithelial integrity and supporting probiotic bacterial growth.

Another study examined hyodeoxycholic acid, showing effects on bile-acid-related signaling, tight-junction expression and Lactobacillus enrichment.

Researchers also evaluated combinations of Bacillus-based biotics and enzymes, reporting changes in immune competence together with lower pathogenic bacterial loads, particularly Mycoplasma spp.

Nutrition can also influence resilience to challenge

Some nutritional interventions may become particularly important when animals encounter infectious or inflammatory pressure.

For example, one of the studies found that intramuscular iron administration supported intestinal barrier function and reduced inflammatory damage in pigs challenged with ETEC.

Zinc oxide was also associated with changes involving metabolic adaptation, immune regulation and intestinal integrity. However, its regulatory phase-out reinforces the need to identify other nutritional strategies capable of supporting these functions.

The broader implication is that nutrient status can influence more than growth. It can also affect how effectively an animal responds when its intestinal system is challenged.

Farm conditions can change the nutritional response

Perhaps one of the most useful findings for commercial production is that the environment can sometimes exert a stronger effect than the diet itself.

One study comparing nutritional and sanitary influences found that hygiene conditions and pathogen exposure had a greater impact on gut microbial composition than dietary amino acid supplementation.

This provides an important explanation for why nutritional interventions do not always produce identical results between experimental facilities or commercial farms.

A microbiome change is not automatically a performance benefit

The collection also offers a useful caution against interpreting every microbial shift as a positive production outcome.

In research evaluating propolis and probiotics, supplementation altered microbial populations, but crude propolis did not improve early growth or reduce post-weaning diarrhea.

This distinction is particularly relevant as functional feed ingredients become increasingly associated with microbiome claims.

Changes in microbial composition can provide valuable information about biological mechanisms, but their practical relevance should ultimately be considered alongside growth, health, diarrhea incidence, intestinal function and other animal-level outcomes.

Could piglet gut health begin with the sow?

Some of the most interesting findings summarized in the editorial occur before piglets even reach the nursery.

Maternal nutrition is increasingly being investigated as a way to influence fetal development, neonatal energy availability, intestinal maturation and immune development.

In one study, supplementation of sow diets with 3-hydroxyisobutyric acid reduced variation in birth weight within litters and improved neonatal energy availability through effects involving placental lipid transport.

Another maternal strategy involving fatty-acid supplementation improved sow productivity and was associated with stronger intestinal barrier function and mitochondrial integrity in offspring, together with reduced inflammatory injury.

Supplementation with chitosan oligosaccharides was also associated with improvements in milk quality, litter performance and neonatal immune development, alongside changes in microbial and antioxidant pathways.

From products to nutritional systems

What emerges from this body of research is not evidence for one universal gut-health solution. Instead, it supports a more integrated way of thinking about swine nutrition.

Enzymes can influence digestion. Fermentation metabolites can affect the hindgut environment. Prebiotics and biotics can interact with microbial communities. Minerals can influence physiological resilience. Maternal nutrition can affect development before birth.

But these mechanisms ultimately converge within the same animal.

MICROBIOTA — influencing fermentation and interactions between microbes and host

INTESTINAL BARRIER — maintaining the interface between the gut lumen and the animal

IMMUNE FUNCTION — shaping responses to microbial and inflammatory challenges

MATERNAL NUTRITION — influencing piglet development before nursery feeding begins

PRODUCTION ENVIRONMENT — determining the hygiene and pathogen pressures under which nutritional strategies must work

What does this mean for swine nutrition?

The findings suggest that the future of gut-health nutrition may depend less on identifying another standalone additive and more on matching complementary nutritional tools to the biological challenges animals are actually facing.

That also means asking more precise questions. Is poor performance being driven primarily by inadequate digestion? Excess substrate reaching the hindgut? Barrier disruption? Pathogen pressure? Immune activation? Early-life development? Or several of these factors simultaneously?

The answer may determine which nutritional strategy is most appropriate.

Importantly, the research also demonstrates why results from functional ingredients can vary among studies and farms. Diet is only one component of a dynamic system involving microbiota, host physiology and environmental exposure.

Future research will be important for determining which combinations of nutritional interventions work synergistically and under which production conditions. This could help develop more precise feeding programs capable of supporting animal health, welfare and productive performance while reducing dependence on conventional antimicrobial tools.

Source

Jang, Y.D., Jang, J.C. & Hong, J. (2026). Editorial: Advances in nutritional strategies for optimizing swine growth performance and gut health. Frontiers in Veterinary Science, 13:1910884. DOI: 10.3389/fvets.2026.1910884.