NUTRITION, IMMUNE SYSTEM ENHANCEMENT, AND PHYSIOLOGY OF AQUATIC ANIMALS
Location: Aquatic Animal Health Research
Title: Utilization of soybean products in non-salmonid marine fish diets
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: November 15, 2007
Publication Date: February 25, 2008
Citation: Peres, H., Lim, C.E. 2008. Utilization of soybean products in non-salmonid marine fish diets. In: Lim, C.E., Webster, C.D.; and Lee, C.S.; editors. Alternative Protein Sources in Aquaculture Diets. New York, NY: Haworth Press. p. 281-312.
Current feeds for marine finfish are heavily dependend on fish meal and fish oil to meet their critical protein and lipid requirements. Due to the increased demand, uncertain availability, and rising costs of fish meal and oil, however, several ingredients of plant origin have been evaluated as potential replacements of fish meal and oil. Soybean products, because of their consistent suply and quality and low costs, have received the most attention. This paper provides a review on nutrient composition and antinutritional factors, nutritional values, and use of soybean products in non-salmonid marine finfish.
Proximate compostion of soy products varies depending on the types of products. However, amino acid content of soy products (expressed as percent of protein)and fatty acid composition of soy oil (expressed as percent of total fatty acids) are relatively consistent. Soybean products have one of the best amino acid profiles among plant proteins for meeting the essential amino acid requirements of marione finfish. Compared to fish meals, protein from soy products are deficient in sulfur-containing amino acids, methionine, and cystine. Soy oil is a rich source of linoleic and linolenic acids. Soybeans also contain a number of antinutritional factors, such as trypsin inhibitors, oligosaccharides, phytin, lectins, saponins, estrogens, and allergens. Some of these antinutritional factors can be inactivated by heat treatments or solvent extraction.
Protein and energy digestibility of soybean meals and full-fat soybean meal by marine fish are relatively high but are generally lower than those of fish meal. These values for soy protein concentrate are comparable to those of fish meal. The lower digestibility of soybean meal relative to soy protein concentrate may be attributed to the presence of high hevels of indigestible oligosaccharides in soybean meals. Large fish digest soybean and meal protein better than small juveniles.
Various soybean products have been used successfully as partial substitutes for fish meal in marine fish diets. Approximately 25 to 67% of dietary fish meal can be substituted by soybean products, depending on the species of fish and type of product. Milkfish and red drume can tolerate higher levels of dietary inclusion of soy products than gilthead seabream, European seasbass, turbot, Japanese flounder, or yellowtail. Higher levels of fish meal can also be substituted if soy protein concentrate is used. Supplementation of methionine, lysine, and phosphorus has been shown to improve the nutritional values of soy products. Palatability enhancers or attractants have also been used to increase consumption of feeds containing high levels of soy products. Since soy oil does not contain n-3 highly unsaturated fatty acids (n-3 HUFA), which are dietary essentials for marine fish, soy oil cannot be used as the sole lipid source in diets of marine fish. Once, howeverm the dietary essential fatty acids have been met, soy oil can be included to meet the energy needs.