Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2013
Publication Date: 12/5/2013
Citation: Cummins, V.C., Webster, C.D., Thompson, K.R., Velasquez, A. 2013. Replacement of fish meal with soybean meal, alone or in combination with distiller’s dried grains with solubles in practical diets for Pacific white shrimp, Litopenaeus vannamei, grown in a clear-water system. Journal of the World Aquaculture Society. 44(6):775-785. Interpretive Summary: Global aquaculture production of shrimp has grown dramatically within the last two decades. Specifically, the Pacific white shrimp generated $11 billion from a production volume of 2.7 mmt in 2010, accounts for 15 percent of the total value of internationally-traded fishery products, and is currently the most valuable single aquaculture commodity. Over 90% of farmed shrimp rely on high protein diets containing high percentages of marine fish meal (FM) but it is the most expensive protein ingredient in shrimp diets. Diet costs can account for between 50-80% of a producer’s operational costs, and thus directly influences producer profitability. Among the plant-protein ingredients, soybean meal (SBM) has received the most attention and is the most widely-used plant-based protein ingredient in aquaculture diets. However, growth of shrimp is reduced when SBM is the only protein ingredient in a diet. Additionally, soybean meal prices have risen by 118% since 1998 from USD $197 to $431/ton. A potential candidate ingredient for use in combination with SBM is distiller’s dried grains with solubles (DDGS), a co-product of ethanol fuel production and the beverage distilling industry. Ethanol production in the United States has undergone significant expansion within the last 10 years as a result of mandates for biofuel use in the U.S. Energy Acts of 2005 and 2007. No studies have been conducted to evaluate the partial replacement of SBM with increasing levels of DDGS in shrimp diets so the objective of this study was to evaluate the ability of DDGS to partially replace SBM as the primary protein source in diets for juvenile Pacific white shrimp. After eight weeks, shrimp fed a diet containing 20% FM were significantly larger and had a better feed conversion ratio than shrimp fed all other diets. This indicates that total replacement of FM by either SBM or DDGS did not grow shrimp as well as a diet with FM and that further research is needed to find a formulation which will grow shrimp as well as feeding a diet with FM.
Technical Abstract: The objective of this study was to evaluate inclusion of distiller’s dried grains with solubles (DDGS) as partial replacement of commercial, solvent-extracted soybean meal (SBM) in fish meal-free diets for Pacific white shrimp, Litopenaeus vannamei. Aquaria connected to a recirculating biofiltration system were utilized to evaluate growth, survival, and feed conversion of shrimp during the 8-wk feeding trial. Each 110-L aquarium was stocked with 15 shrimp (mean individual weight 0.99 g) and fed one of five diets: a diet containing 20% fish meal (FM) which served as the control (Diet 1); a diet containing 0% FM and 52.5% SBM (Diet 2); and diets containing 0% FM and either 10%, 20%, or 30% DDGS as partial replacement of SBM (Diets 3, 4, and 5, respectively). Shrimp were fed according to a pre-determined feeding chart five times daily (0730, 1030, 1330, 1630, and 1930 h) and there were three replicates per dietary treatment. The results from the feeding trial demonstrated that final weight, weight gain (g), and percentage weight gain were significantly higher (P < 0.05) for shrimp fed Diet 1 (10.96 g, 10.01 g, and 1051%, respectively) compared to shrimp fed diets containing DDGS; however, shrimp fed diets containing DDGS had similar (P > 0.05) final weight, weight gain (g), and percentage weight gain as shrimp fed a diet containing 0% FM and 52.5% SBM (Diet 2). Feed conversion ratio (FCR) of shrimp fed Diet 1 (2.84) was significantly lower (P < 0.05) compared to shrimp fed any other diet. Survival (%) was not different (P > 0.05) among treatments and averaged 77.3% for the study. This study demonstrated that practical shrimp diets containing no FM had an adverse impact on growth performance of white shrimp when grown in a clear-water system and that further research is needed to refine diet formulations when culturing shrimp in these systems when attempting to feed a diet without FM.