Use of distiller’s dried grains with solubles in tilapia diets

Chhorn Lim, Supervisory Nutrition Scientist, Aquatic Animal Health Research Unit, USDA, ARS, Auburn, USA

Distiller’s dried grains with solubles (DDGS) are currently readily available and less expensive than other conventional protein sources. However, its nutrient content and nutritional value vary with the source and quality of grain, fermentation and drying processes and the quantity of distiller’s solubles added. Generally, corn and wheat DDGS are deficient in lysine and methionine for tilapia, with lysine being the most limiting. Feeding studies showed that 20 - 30% corn or wheat DDGS can be included in tilapia diets without requiring lysine supplementation. With lysine supplementation, DDGS at levels of 40% or higher can be used without affecting growth and feed 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 energy and essential fatty acid for tilapia. High concentrations of xanthophylls in corn DDGS may impart yellow pigment in fish flesh if included at high levels. Considering various factors affecting the nutritional value and quality of pellet and fish product, 15 - 20% DDGS appears to be optimum in diets of tilapia.