Location: Aquatic Animal Health Research
Title: Distillers dried grains with solubles as alternative protein source in diets of tilapia Authors
Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 5, 2011
Publication Date: December 1, 2011
Repository URL: http://handle.nal.usda.gov/10113/56494
Citation: Lim, C.E., Li, E., Klesius, P.H. 2011. Distillers dried grains with solubles as alternative protein source in diets of tilapia. Aquaculture. 3:172-178. Technical Abstract: Research efforts by nutritionists to reduce feed costs have resulted in increased use of lower cost alternative plant proteins in fish feed formulations as replacements of fish meal and other expensive protein sources. Distillers dried grains with solubles (DDGS), a dried residue that remains after the fermentation of grain mash by selected yeasts and enzymes to produce ethanol and carbon dioxide, is currently readily available and less expensive than other conventional protein sources on a per unit protein basis. The nutrient content of DDGS varies with the source and quality of grain as well as between and within ethanol plants due to fermentation time and efficiency, the drying process and the quantity of distiller’s solubles added. Relative to the grain sources, nutrient concentrations in DDGS approximately triple due to the utilization of starch during fermentation process. Generally, corn and wheat DDGS are deficient in lysine and methionine for most fish species, with lysine being the most limiting, but do not contain antinutritional factors. Research evaluating the nutritional value of DDGS in fish diets has shown that DDGS derived from corn and wheat are promising protein sources in fish diets, particularly for omnivorous species such as tilapia. Results of several studies showed that, depending on the composition and nutrient concentrations of the basal diets, 20 to 30% corn or wheat DDGS can be included in tilapia diets without requiring lysine supplementation. With supplementation of lysine, DDGS at levels of 40% or higher can be used without affecting growth performance and feed utilization efficiency. DDGS also contain yeast, a rich source of beta glucan and nucleotides that have been reported to enhance immunity and disease resistance in fish. Corn DDGS, due to its high oil content that is rich in linoleic acid, is an excellent source of essential fatty acid for tilapia. High concentrations of xanthophylls present in corn DDGS may impart yellow pigment in fish flesh if included at high levels. Taking into consideration various factors affecting the nutritional value of diets and the quality of pellet and fish product, 15 to 20% DDGS appears to be optimum in diets of tilapia.