Dietary seaweed (Saccharina latissima) supplementation in pigs induces localized immunomodulatory effects and minor gut microbiota changes during intestinal helminth infection

Seaweed’s Nutritional Arsenal

Brown seaweeds like Saccharina latissima contain:

Polysaccharides (laminarin, fucoidan): Prebiotics that feed beneficial gut bacteria.

Fatty acids: Anti-inflammatory and antimicrobial agents.

Minerals: Iodine, zinc, and iron, crucial for immune function.

Studies show these compounds enhance intestinal barrier integrity, upregulate mucin production, and reduce pro-inflammatory cytokines .

Helminth-Gut Microbiome Crosstalk

Helminths like Oesophagostomum dentatum (nodular worms) disrupt gut microbiota balance, often reducing microbial diversity and promoting inflammation . For example, Prevotella copri—a bacterium linked to gut dysbiosis—blooms during infections, worsening pathology .

Key Findings: Seaweed’s Localized Effects

A 2023 study fed pigs 8% fermented Saccharina latissima (Fer-SL) and infected them with helminths. Here’s what they discovered:

Gut Microbiota Shifts

Taxonomic Change	Impact	Evidence
↑ Firmicutes, Tenericutes	Linked to improved fiber digestion
↓ Prevotella copri	Reduced inflammation risk
↑ Oscillospira	Associated with anti-inflammatory metabolites

Table 1: Microbiota changes in pigs fed Fer-SL.

Fer-SL increased α-diversity (a marker of gut health) and promoted beneficial bacteria like Clostridiales and Bacteroides .

Site-Specific Immune Modulation

• Jejunum: Attenuated infection-induced inflammation (e.g., reduced IL1B2 and NFKB1 expression).
• Colon: Amplified type-2 immune responses (e.g., ↑ ARG1, CCL22), critical for worm expulsion .

Table 2: Immune gene expression changes in Fer-SL-fed pigs.

Gene	Function	Fold Change (Jejunum)	Fold Change (Colon)
IL1B2	Pro-inflammatory signaling	↓ 1.3	–
ARG1	Tissue repair	–	↑ 1.3

No Direct Antiparasitic Effect

Despite in vitro anti-helminth activity, Fer-SL did not reduce worm burdens or egg counts . However, it mitigated infection-driven intestinal damage, suggesting indirect benefits .

Why This Matters for Sustainable Farming

Reducing Antibiotic Reliance: Seaweed’s prebiotic properties could lower antibiotic use in livestock .

Climate Resilience: Seaweeds absorb CO₂ during growth, aligning with eco-friendly practices .

Cost-Effective Nutrition: Fermentation enhances bioavailability, maximizing nutrient uptake .

Future Directions and Challenges

Long-Term Safety: High iodine content in seaweed requires dose optimization .

Mechanistic Insights: How do seaweed metabolites directly interact with helminths?

Broader Applications: Testing in poultry and cattle could expand its utility .

Conclusion: A Seaweed-Powered Future

While fermented Saccharina latissima didn’t eliminate parasites, its ability to remodel the gut environment and fine-tune immunity offers a promising tool for sustainable livestock management. As research unravels diet-microbe-immune interactions, seaweed could become a staple in the fight against helminths—and a win for planetary health.

References Cited in Evidence: