Protein Substitutes Hold Promise for Aquaculture
The U.S. is the top producer of hybrid striped bass, and a Texas A&M AgriLife team is working to improve the fishes’ health, growth and productivity by developing effective nutritional strategies to substitute fishmeal and other protein feedstuffs in the farmed bass diets.
Aquaculture is the fastest-growing agricultural enterprise in the world. The field is expected to continue growing to provide seafood for the world’s expanding population.
Some fish species produced in aquaculture, such as the omnivorous catfish and carps, consume diets without any fishmeal. However, more carnivorous species such as hybrid striped bass have traditionally been fed diets with a considerable amount of fishmeal, which is a very nutritious but costly marine feedstuff. There is a growing interest in using plant proteins such as soybean meal to replace fishmeal in aquafoods, but success has been variable.
Researchers found that glycine, the most abundant amino acid in the body of fish and fishmeal, is relatively low in plant proteins. Based on results of a preliminary study, they believe that dietary glycine plays an important role in hybrid striped bass growth by maximizing protein synthesis, antioxidative capacity and creatine production in their tissues.
Glutamate, the second most abundant amino acid in the body of fish and fishmeal, acts with glycine to promote metabolic processes. The scientists believe both glutamate and glycine should be considered “functional amino acids” in animal nutrition.
Glutamate and glycine are inexpensive amino acids that hold promise as cost-effective feed additives. In addition, fish are excellent animal models to translate the basic research findings into the efficient production of high-quality animal protein for human consumption.