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The growing global shortage of high-quality protein sources such as soy protein concentrate and fish meal has intensified the search for sustainable alternatives in animal nutrition. Rapeseed protein has recently emerged as a promising option, and its nutritional value in piglets has been evaluated previously. However, its broader effects on piglet growth and health had not been fully clarified.
Objective: This study examined the impact of replacing soy protein concentrate and fish meal with rapeseed protein in the diets of young piglets.
Methods: A total of 120 piglets, 24 to 25 days old and averaging 7.8 kg in body weight, were assigned to five dietary treatments for 28 days. The control diet contained 5% soy protein concentrate and 5% fish meal. In the experimental diets, either 50% or 100% of soy protein concentrate was replaced with an equivalent amount of rapeseed protein while maintaining fish meal at 5%, or 50% or 100% of fish meal was replaced with rapeseed protein while maintaining soy protein concentrate at 5%.
Results: Overall growth performance was maintained across treatments, indicating that rapeseed protein can successfully replace soy protein concentrate or fish meal without compromising weight gain. Interestingly, complete replacement of soy protein concentrate or partial to complete replacement of fish meal improved feed efficiency, meaning piglets required less feed to gain the same amount of weight. Piglets fed rapeseed protein-based diets also showed higher crude protein digestibility and increased expression of genes involved in amino acid transport, suggesting improved protein utilization. Diets containing rapeseed protein stimulated the secretion of appetite-promoting hormones, reduced inflammatory responses, and enhanced immune function and antioxidant capacity. At the molecular level, replacing soy protein concentrate or fish meal with rapeseed protein increased the expression of genes linked to protein synthesis in both muscle (mTOR and p70S6K) and liver (mTOR and Akt), indicating greater anabolic activity. Improvements were also observed in intestinal morphology, particularly in the jejunum and ileum, which are key sites for nutrient absorption. In addition, rapeseed protein diets modified the gut microbiota, increasing the relative abundance of beneficial bacterial genera such as Blautia, Gemmiger, and Haldemanella.
Conclusion: In summary, rapeseed protein appears to be a viable and sustainable alternative to soy protein concentrate and fish meal in piglet diets. Its use not only maintains growth performance but also supports digestive efficiency, gut health, immune function, and protein metabolism.
Du Z, Xu H, Sang N, Zhao Y, Zheng P, Wang H, Wang Q, Chen D, Yu B. Effects of rapeseed protein on growth performance, nutrient digestibility, nitrogen balance, serum parameters, and intestinal health of piglets. Animal Nutrition. 2025; 24: 121-135. https://doi.org/10.1016/j.aninu.2025.09.004