ARS | Publication request: Effects of Various Corn Distillers By-products on Growth and Feed Efficiency of Channel Catfish, Ictalurus punctatus

Submitted to: Aquaculture Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 27, 2008
Publication Date: April 1, 2010
Citation: Li, M.H., Robinson, E.H., Oberle, D.F., Lucas, P.M. 2010. Effects of Various Corn Distillers By-products on Growth and Feed Efficiency of Channel Catfish, Ictalurus punctatus. Aquaculture Nutrition. 16:188-193.

Interpretive Summary: Global production of ethanol as an automotive fuel has increased rapidly in recent years, which has resulted in an increasing supply of by-products associated with its production. As supplies increase, prices of distillers grains will become more competitive which should increase their use in animal feeds, thus reducing feed cost. This study examined various corn distillers by-products including distillers grains with solubles (DDGS), distillers solubles (DS), high-protein distillers dried grains (HPDDG), and DS from the corn endosperm (EDS) in diets for channel catfish. Results from the study demonstrate that elevated fat levels in diets containing distillers by-products are partially responsible for the improvement in diet consumption and FER of fish fed the distillers by-products. The presence of DS in the diet appears to further increase diet consumption and FER, and also improve weight gain over the control diets with or without additional fat. Dietary levels of 300 g/kg DDGS and 100 g/kg DS resulted in higher fillet fat compared with the control diet because of high fat content in these ingredients. Distillers by-products contain yellow pigments, which usually vary from plant to plant in concentrations, thus they should be monitored so that the levels do not affect the appearance of the catfish products. Use of distillers by-products to partially replace soybean meal in channel catfish diets could reduce feed cost when the by-products are competitively priced compared with soybean meal and other protein sources.

Technical Abstract: A study was conducted to examine the use of corn distillers by-products in diets and the effects of additional dietary fat on channel catfish, Ictalurus punctatus, performance. Juvenile channel catfish (initial weight: 12.6 g per fish) were stocked in flow-through aquaria and fed one of six practical diets for 9 weeks. Fish fed the control + fat diet consumed more diet and had higher feed efficiency ratio (FER) than fish fed the control diet, but weight gain was not significantly different between fish fed these two diets. Fish fed the diet containing 300 g/kg distillers dried grains with solubles (DDGS) consumed more diet and gained more weight, but had similar FER compared with fish fed the control + fat diet. The diet containing 200 g/kg high-protein distillers grains (HPDDG) resulted in similar diet consumption, weight gain and FER as the control + fat diet. Fish fed the diet containing 100 g/kg distillers solubles (DS) consumed more diet, but had similar weight gain and FER compared with fish fed the 300 g/kg DDGS diet. The presence of distillers solubles in the diet (300 g/kg DDGS, 100 g/kg DS, 100 g/kg EDS diets) appears to increase diet consumption, weight gain, and FER over the control diets with or without additional fat.