Retrospect of fishmeal substitution in largemouth bass (Micropterus salmoides): a review

With the growth of the population, the demand for aquatic products is increasing. Additionally, the development of the aquaculture industry has led to a heightened demand for fishmeal (FM). FM is a high-protein feed raw material made from one or more types of fish, which has been deoiled, dehydrated, and crushed. The world's major FM-producing countries include Peru, Chile, Japan, Denmark, etc., among which exports from Peru and Chile account for about 70% of the total trade volume. However, in recent years, global warming, environmental pollution, and overfishing have gradually declined marine fishery resources. The shortage of high-quality FM and its rising prices have become a significant constraint to the development of fisheries. Consequently, aquaculture nutritionists are actively seeking solutions to reduce the reliance on FM by either enhancing the utilization rate of existing FM or developing new protein sources as substitutes. The challenge of FM replacement has thus emerged as a significant global issue. Largemouth bass (LMB) is one of the more cultured freshwater fishes in the world and is popular among consumers for its delicious and delicate flesh and rich and diverse nutrition. The protein content in feed is an essential factor affecting LMB growth and feed cost. LMB protein requirement is about 40-50%, and the amount of FM added accounts for about 50% of the protein feed. This article reviews the current research status of alternative protein sources, including plant proteins, livestock and poultry by-product proteins, insect proteins, and single-cell proteins. This research is significant for exploring feed formulation and cost reduction for LMB.