Lipid extracted distillers dried grains with solubles (LE-DDGS) as a partial replacement for soybean meal in hybrid tilapia (Oreochromis niloticus × O. aureus) diets

Abstract

Feed costs are primarily driven by the cost of protein sources in the feed. Substitution of expensive protein sources with lower cost ingredients would potentially reduce feed cost. Lipid-extracted distillers dried grains with solubles (LE-DDGS) is a relatively new product of distillers dried grains with solubles (DDGS) which could be used as an alternative protein source in tilapia feed formulations. Two growth trials were conducted to evaluate the substitution of soybean meal with LE-DDGS in practical diets for hybrid tilapia (Oreochromis niloticus×Oreochromis aureus). The first trial evaluated five levels of LE-DDGS (0, 200, 300, 400 and 500gkg−1) in a practical diet containing 360gkg−1 protein and 60gkg−1 lipid. The result indicated that increasing levels of LE-DDGS generally resulted in a reduced growth of hybrid tilapia with a significant (P<0.05) depression in performance when incorporated in the diet at 400 and 500gkg−1. The second study evaluated four levels of inclusion (0, 200, 400 and 500gkg−1) with lysine supplements and a fifth diet with an additional 20gkg−1 lipid (27gkg−1 lysine and 80gkg−1 lipid). The result demonstrated that all diets promoted good performance of hybrid tilapia. In conclusion, LE-DDGS could be a promising protein source as a substitute for soybean meal at levels up to 300gkg−1 of the diet. With lysine and possible lipid supplement, LE-DDGS as much as 500gkg−1 produced good performance in hybrid tilapia diet. As the ethanol industry continues to refine their process and shift the composition of co-products that are sold on the market, it is recommended that the new product should re-evaluated for their efficiency. Statement of relevanceThe present study can show that DDGS can be used as a substitution of soybean meal in tilapia fish. Given the rise in soybean meal prices, DDGS can be used in aquacultural feeds along with supplementation of lysine as a replacement of the more expensive plant derived protein source.