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Pig diets mainly rely on soybean meal but its production can harm the environment through soil degradation, deforestation, and loss of biodiversity. Spirulina, a type of microalgae, could be a more sustainable alternative, but more information about its effects on pig growth and carcass quality is needed.
Objective: This study tested how replacing part or all the soybean meal with spirulina affects pig growth, carcass quality, and meat characteristics.
Methods: Eighty-eight pigs (both gilts and barrows), starting at about 52 kg, were divided into four groups. One group received a conventional diet based on cereals and soybean meal, while the other three groups had diets where 33%, 66%, or 100% of soybean meal was replaced with spirulina. Each group had two pens of 11 pigs, equipped with electronic feeders that recorded individual feed intake. After 138 days, when pigs reached around 175 kg, they were slaughtered to evaluate carcass traits and meat quality from loin samples.
Results: Replacing soybean meal with spirulina at different levels did not affect growth performance. Pigs across all dietary treatments showed similar final body weight, daily gain, feed intake, and feed efficiency, with average weight differences between groups being less than 3 kg. Ultrasound backfat thickness was also comparable at both the start and end of the trial. No significant differences in carcass weight or commercial cuts (loin, ham, fat) were observed between dietary groups with varying spirulina levels. However, barrows had fatter carcasses, with 5% thicker backfat, 7% heavier lard, and 4% lighter loins compared to gilts. The contribution of loins to total carcass weight was about 3% lower and lard 9% higher in barrows. Partial or full replacement of soybean meal with spirulina did not affect loin quality traits, including pH, color, shear force, and chemical composition. Only minor differences in cooking losses were found among spirulina levels, but no clear pattern or significant deviation from the control group.
Conclusion: Replacing soybean meal with spirulina does not affect growth performance, carcass traits, or meat quality.
Don G, Giannuzzi D, Toscano A, Schiavon S, Gallo L. Growth performance and carcass traits of growing and finishing pigs fed diets with a partial to total replacement of soybean meal with Spirulina powder. Journal of Animal Science and Biotechnology. 2025;16(1):77. https://doi.org/10.1186/s40104-025-01197-7
