Sea to Feed

The inclusion of seaweed in swine diets may help reduce the overall carbon footprint of pork production, as well as contribute to animal and environmental health. Research indicates that seaweed is a promising source of dietary supplementation for the pig production industry and can play a vital role in improving swine health.

But studies also show that the nutritional composition of seaweed can vary greatly depending on the species, time of harvest, geographic location, environmental conditions, and extraction/processing protocols. Further research is necessary to continue advancements in determining the optimal conditions and methods for including seaweed as a nutritional strategy for swine.

Seaweed, also known as macroalgae, has been used as a livestock feed for thousands of years in many coastal regions around the world—since 45 BC in Greece.1 Although, historically, pig producers have known from their experiences that seaweed is a beneficial feed source, the science of the times didn’t support evidence to that effect.1  

However, due to scientific advancements, we now know that seaweeds have a complex structure that consists of unique chemical compositions. They can be rich in proteins, vitamins, minerals (both micro- and macroelements), amino acids, polysaccharides, lipids, and antioxidant compounds like polyphenols. Some of these bioactive components give seaweed specific nutritional advantages over traditional feed compositions.

Science shows that seaweeds have antibacterial, antimicrobial, anti-inflammatory, antioxidative, anticarcinogenic, antihypertensive, antiviral, antifungal, immunomodulatory, prebiotic, and probiotic effects that can greatly enhance the health of animals. Numerous recent studies demonstrate that using seaweed as a supplement in swine feed has significant health benefits, particularly in weaning piglets.

Weaning Piglets

Weaning is the most difficult stage of a pig’s life as it transitions from the nutrients of sow’s milk to those of solid or liquid feed, while moving into a new housing environment and adjusting to new social relationships with other members of the herd. These stressors all contribute to an imbalance of the gut’s microbiota, known as dysbiosis, which can result in diarrhea (scours), malnutrition, intestinal infection, disease risk, and even death.

Maintaining a healthy gut is crucial to ensuring that piglets can properly digest their feed and absorb its nutritional components efficiently. Developing an established gut microbiota in weaning piglets can prevent diarrhea, improve weight gain, enhance welfare, and reduce pig mortality.

Research indicates that seaweed supplementation helps reduce the negative impacts of weaning and other environmental challenges as it regulates a piglet’s gut microbiota and boosts its immune system.2, 3 Additionally, several studies show that seaweed can actually reduce pathogenic bacteria in the gut, such as Escherichia coli and Salmonella enterica, while increasing beneficial bacteria, such as Lactobacillus and Bifidobacterium spp.4, 5

Various feeding trials with seaweed supplements have resulted in better average daily feed intake (ADFI), increased average daily gain (ADG), and reduced intestinal dysfunction for weaning piglets.6, 7, 8, 9

Sows and Boars

Several studies indicate that supplementing a sow’s feed with seaweed has positive effects on her health and performance, as well as that of her offspring.5, 10, 11 For instance, suckling piglets had increased IgG and IgA concentrations, indicating an immunomodulatory property of the seaweed supplement fed to the sows that passes to her litter.11 In addition, the suckling piglets of seaweed-supplemented sows had a lower colonic E coli population and a greater Lactobacillus:E coli ratio at weaning, which can reduce the occurrence of postweaning diarrhea.11

In researching boars, one study concludes that using seaweed as a feed supplement can increase sperm motility, as well as important sperm proteins.12 Another study suggests a correlation between a reduced semen utilization rate in boars with gut microbiota imbalance, further highlighting the importance of a healthy gut.13

Further Enhancements


Several recent studies have determined that seaweeds have a complex cell wall structure that can be difficult for monogastric animals like pigs to thoroughly digest, resulting in an inability to reap the full nutritional benefits that seaweeds offer.14

Realizing the additional potential nutritional benefits of seaweed for pigs, some researchers have experimented with further enhancing its digestibility through carbohydrase enzymes or fermentation techniques. Both processes show promise in increasing the nutrient bioavailability, making the full spectrum of seaweed’s bioactive components easier for the swine gastrointestinal system to digest and absorb.14, 15

Additional Benefits

In addition to improved herd health and productivity, including seaweed as a feed supplement can result in the following benefits:

  • Fewer veterinary visits and bills
  • Lower amounts of protein needed in feed, reducing the total cost
  • Improved quality and nutritional value of meat

Global Benefits

Seaweed is a more sustainable feed ingredient alternative than corn, soybean meal, and other grains because it doesn’t require fresh water, pesticides, external fertilizer, or arable land for cultivation.

  • Agriculture consumes 70% of all available fresh water.16, 19
  • 98% of the fresh water used in animal production is for growing feed crops and providing grazing for livestock.17
  • Agriculture consumes 40% to 50% of the Earth’s terrestrial land.18
  • 36% of the world’s crop calories are fed to livestock.19
  • The runoff from pesticides and fertilizers impacts streams, rivers, lakes, bays, and coastal waters, resulting in serious environmental, economic, and human health issues.20

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2. Corino C, Modina SC, Di Giancamillo A, Chiapparini S, Rossi R. (2021) Prebiotic effects of seaweed polysaccharides in pigs. Animals, 11, 1573.

3. Michalak I, Tiwari R, Dhawan M, Alagawany M, Farag MR, Sharun K, Emran TB, Dhama K. (2022) Antioxidant effects of seaweeds and their active compounds on animal health and production - a review. Vet Q, 42(1), 48–67.

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12. Han H, Zhou Y, Xiong B, Zhong R, Jiang Y, Sun H, Tan J, Zhang B, Guan C, Schroyen M, Chen L, Zhao Y, Zhang H. (2022) Alginate oligosaccharides increase boar semen quality by affecting gut microbiota and metabolites in blood and sperm. Front Microbiol, 13:982152.

13. Guo L, Wu Y, Wang C, Wei H, Tan J, Sun H, et al. (2020) Gut microbiological disorders reduce semen utilization rate in Duroc boars. Front Microbiol, 11:581926.

14. Ribeiro DM, Pinto RMA, Lopes PA, Pestana JM, Alfaia CM, Costa MM, Carvalho DFP, Mourato MP, de Almeida AM, Freire JPB, Prates JAM. (2023) Effect of Laminaria digitata dietary inclusion and CAZyme supplementation on blood cells, serum metabolites and hepatic lipids and minerals of weaned piglets. Scientific Reports, 13(1).

15. Hui Y, Tamez-Hidalgo P, Cieplak T, et al. (2021) Supplementation of a lacto-fermented rapeseed-seaweed blend promotes gut microbial- and gut immune-modulation in weaner piglets. J Animal Sci Biotechnol, 12, 85.

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