Research Progress on Feeding Value of Azolla and Its Application in Circular Agriculture

The shortage of feed protein resources is the core issue restricting the sustainable development of China's livestock production. Developing indigenous unconventional protein feeds is an important approach to ensuring national food security. This paper systematically reviews the nutritional and bioactive components of Azolla, focusing on the research progress of its applications in livestock production and circular agriculture. Azolla is rich in nutrients, containing various conventional nutrients for animal growth such as amino acids and minerals, as well as multiple bioactive components such as flavonoids and polyphenols. In livestock production, Azolla can partially replace traditional feeds such as fish meal and concentrate feeds. It not only maintains the growth performance of fish, poultry and pigs, ruminants, and special economic animals, but also significantly reduces feed costs and enhances intestinal health, carcass quality and milk yield. In addition, circular agricultural models centered on Azolla, such as the "rice–Azolla–fish/duck" and "pig–biogas–Azolla–fish" systems, have demonstrated favorable ecological and economic benefits. In the future, three dimensions about systematic evaluation of germplasm resources, standardization of Azolla feeding technology, and industrialization of circular agricultural models should be synergistically advanced to provide technical support for soybean meal reduction and replacement as well as the green and low-carbon transition of agriculture.