Sustainable Valorization of Tomato Pomace (Lycopersicon esculentum) in Animal Nutrition: A Review

SIMPLE SUMMARY: The global annual production of tomatoes (Lycopersicon esculentum) is 170 million tons. After industrial processing, a large amount of tomato pomace is produced because it contains a high amount of water and nutrients. Therefore, if it is not used properly, not only will resources be wasted, but the environment will be polluted. In addition, tomato pomace is also rich in antioxidants, such as carotenoids, lycopene, and flavonoids, which help to improve the antioxidant properties of animals. Hence, this review focuses on the nutritional content of tomato pomace and the effects of its application in livestock. ABSTRACT: Under the background of the current shortage of feed resources, especially the shortage of protein feed, attempts to develop and utilize new feed resources are constantly being made. If the tomato pomace (TP) produced by industrial processing is used improperly, it will not only pollute the environment, but also cause feed resources to be wasted. This review summarizes the nutritional content of TP and its use and impact in animals as an animal feed supplement. Tomato pomace is a by-product of tomato processing, divided into peel, pulp, and tomato seeds, which are rich in proteins, fats, minerals, fatty acids, and amino acids, as well as antioxidant bioactive compounds, such as lycopene, beta-carotenoids, tocopherols, polyphenols, and terpenes. There are mainly two forms of feed: drying and silage. Tomato pomace can improve animal feed intake and growth performance, increase polyunsaturated fatty acids (PUFA) and PUFA n-3 content in meat, improve meat color, nutritional value, and juiciness, enhance immunity and antioxidant capacity of animals, and improve sperm quality. Lowering the rumen pH and reducing CH(4) production in ruminants promotes the fermentation of rumen microorganisms and improves economic efficiency. Using tomato pomace instead of soybean meal as a protein supplement is a research hotspot in the animal husbandry industry, and further research should focus on the processing technology of TP and its large-scale application in feed.