Research progress on active components of tea by-products and its application in animal production.

China is a major tea-producing nation, and the comprehensive utilization of tea has always been an important direction for the development of the tea industry. In addition to the picking, production, and consumption of tea leaves, a large amount of by-products are generated, such as tea juice, tea residue, tea powder, and so on. These tea by-products contain a number of bioactive substances, such as polyphenols (catechins, flavonoids, proanthocyanidins), pigments, alkaloids (caffeine, theobromine, theophylline), amino acids, and tea polysaccharides, etc. They exhibit various biological functions, including anti-virus, anti-oxidation, blood glucose reduction, and gastrointestinal health improvement. Tea by-products can effectively enhance productivity and the quality of livestock products, as well as strengthen the body's disease resistance. Tea by-products are increasingly applied in livestock farming, with widespread applications in animal production. The article reviews the active ingredients and biological functions of tea by-products, as well as their applications in animal production, providing a reference for the further promotion and utilization of tea by-products in animal production. [ABSTRACT FROM AUTHOR]