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Protein feeds, especially soybean meal, are essential but raise major environmental and sustainability concerns in pig production. Arthrospira platensis (Spirulina), a high-protein aquatic biomass, has emerged as a promising alternative, though its effects in pigs remain insufficiently studied. While previous research suggests potential benefits for gut health and metabolism, results are inconsistent and mostly limited to low inclusion levels.
Objective: This study evaluates the impact of partially to fully replacing soybean meal with this ingredient on gut morphology and blood health in growing-finishing pigs.
Methods: A total of 88 pigs were fed one of four diets: a control diet based on soybean meal, or diets where 33%, 66%, or 100% of soybean meal was replaced with spirulina, while maintaining similar energy, protein, and amino acid levels. Blood samples were collected at the beginning and end of the trial, and intestinal tissues were analyzed at slaughter to assess gut structure.
Results: Overall, pigs maintained stable metabolic, oxidative, and inflammatory profiles regardless of diet, with no signs of impaired liver or kidney function. Intestinal structure was also preserved across all treatments, although some changes in ileal morphology were observed as spirulina inclusion increased, including wider villi and deeper crypts, along with a slight increase in inflammation score. Contrary to findings in other species, no clear antioxidant or anti-inflammatory effects of spirulina were detected under these conditions.
Conclusion: Replacing soybean meal with spirulina did not negatively affect gut integrity or overall physiological status, supporting its potential as a safe and sustainable protein source in pig production.
Giannuzzi D, Toscano A, Don G, Verdiglione R, Schiavon S, Gallo L. Gut morphology and blood biochemical parameters of growing pigs fed diets with a partial to total replacement of soybean meal with Arthrospira platensis. Frontiers in Veterinary Science. 2026; 13: 1728650. https://doi.org/10.3389/fvets.2026.1728650
