Production of High Protein Feeds from Brewer's Spent Grain to Replace Fishmeal in Aquaculture Diets

View the project final report

Commodities

• Animals: fish

Practices

• Animal Production: aquaculture, feed formulation
• Sustainable Communities: local and regional food systems, values-based supply chains

The limited supply and high price of fishmeal are emerging as big challenges to the sustainable growth of the U.S. aquaculture farmers. Thus, there is a need to seek alternative feed sources for aquaculture production. The long-term goal of this research is to produce a sustainable and cost-effective alternative to fishmeal in shrimp feeds to improve the growth of the aquaculture industry. This project was accomplished through a research plan with three objectives: 1. develop an economically feasible fractionation process to produce high-protein feed (PP) from a brewery waste, i.e., brewer’s spent grain (BSG), 2. demonstrate the effectiveness of PP to replace fishmeal via shrimp feeding trials and shrimp quality evaluations, and 3) conduct techno-economic analysis to evaluate the economic feasibility of the conversion of brewer's spent grain to PP. BSG was first subjected to a wet fractionation process to produce PP using different chemical/biological treatments. Under the optimized conditions, the produced PP contained 46% protein, which is an ~100% increase in protein concentration compared with the original BSG. The effectiveness of using high-protein feed as a replacement for fishmeal was then evaluated by shrimp feeding trials. The shrimp diets were prepared by using PP to replace fishmeal at increasing levels (10–70%). The results showed that up to 50% of fishmeal in shrimp feed can be replaced by PP without affecting shrimp growth and feed utilization. The economic analysis showed that the production cost of high-protein feed was $1,044 per metric ton, lower than the market price of fishmeal. Overall, this research benefit aquaculture farmers by providing a low-cost protein alternative to fishmeal and support the brewery industry by providing an alternative way of managing and using brewer’s spent grain. The research findings have been widely disseminated through mainstream public media and have drawn much attention from the agricultural professionals and the brewery industry. 

• Develop an economically feasible fractionation process to produce high-protein feed from brewer’s spent grain.
• Demonstrate the effectiveness of high-protein feed to replace fishmeal via shrimp feeding trials.
• Conduct the techno-economic analysis to evaluate the production cost of the high-protein feed from brewer's spent grain