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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING PRODUCTION STRATEGIES IN CHANNEL CATFISH FARMING

Location: Warmwater Aquaculture Research Unit

Title: Evaluation of corn distillers dried grains with solubles and brewers yeast in diets for channel catfish Ictalurus punctatus

Authors
item Li, Menghe -
item Oberle, Daniel -
item Lucas, Penelope -

Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 5, 2010
Publication Date: September 1, 2011
Citation: Li, M.H., Oberle, D.F., Lucas, P.M. 2011. Evaluation of corn distillers dried grains with solubles and brewers yeast in diets for channel catfish, Ictalurus punctatus. Aquaculture. 42:1424-1430.

Interpretive Summary: Distillers dried grains with solubles (DDGS) from corn is a by-product of ethanol production. It is relatively high in protein (27%) and highly palatable to channel catfish. With the rapid expansion of ethanol production in the United States, the prices for DDGS have become more competitive compared with soybean meal and other plant protein sources. Use of this by-product in catfish feeds would reduce feed cost. However, DDGS contain up to three times of the amount yellow pigments found in yellow corn, and at high levels the pigments can reduce marketability of the catfish product. If levels of pigmented compounds in DDGS can be reduced, more DDGS could be used. Also, the use of brewers yeast has been reported to improve fish growth. A laboratory study was conducted to examine the effect of DDGS, de-pigmented DDGS and brewers yeast in the diet on the growth, feed efficiency, and body proximate composition of juvenile channel catfish. Results demonstrate that diets containing 1% brewers yeast or 30% DDGS support the same level of growth and feed efficiency as a diet containing 5% fish meal for juvenile channel catfish. Hexane extraction method used in the present study removed almost all fat in DDGS, but was not effective in removing the yellow pigments. Ethanol extraction of DDGS removed most of the fat and almost all yellow pigments. The diet containing ethanol extracted DDGS resulted in significantly lower growth and feed efficiency compared with the diet containing regular DDGS. However, the weight gain of fish fed ethanol extracted DDGS was intermediate compared with fish fed the all-plant control, fish meal control, and 1-2% brewers yeast diets. Ethanol extracted DDGS could potentially be used at high levels as a substitution of soybean meal without causing yellow pigment deposition in catfish flesh, provided that the ethanol extraction process is proven economical. Brewers yeast, used at 1-2% of the diet, appears to improve weight gain and FER over the all-plant control diet.

Technical Abstract: A study was conducted to examine the use of distillers grains with solubles (DDGS), ethanol extracted DDGS (EDDGS), and brewers yeast in channel catfish, Ictalurus punctatus, diets. Diets containing these ingredients were compared with all-plant and fish meal control diets. Juvenile channel catfish (initial weight: 9.1± 0.2 g/fish) were stocked in flow-through aquaria and fed one of six practical diets for 8 weeks. Diets containing 1% brewers yeast or 30%DDGS supported the same level of growth and feed efficiency ratio (FER) as the diet containing 5% fish meal. Ethanol extraction effectively removed most of the fat and yellow pigments in DDGS. The diet containing 30% EDDGS resulted in significantly lower growth and FER compared with the diet containing DDGS. However, the weight gain of fish fed the EDDGS diet was intermediate compared with fish fed the all-plant control, fish meal control, and 1% and 2% brewers yeast diets. The EDDGS could potentially be used at high levels as a substitution for soybean meal without causing yellow pigment deposition in catfish flesh, provided that the ethanol extraction process is proven economical. Brewers yeast, used at 1-2% of the diet, appears to be effective at improving weight gain and FER of channel catfish over the all-plant diet.

Last Modified: 12/20/2014
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