February 15-18, 2009 Washington State Convention Center Seattle ...

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AMINO ACID SUPPLEMENTATION AND DIGESTIBILITY OF PRACTICAL ORGANIC
DIETS FOR NILE TILAPIA, Oreochromis niloticus, CONTAINING SOYBEAN MEAL AND
COMMERCIAL YEAST EXTRACT AS TOTAL REPLACEMENTS OF FISH MEAL
Kimberly A. Trosvik*, Linda S. Metts, Kenneth R. Thompson and Carl D. Webster
Aquaculture Research Center
Kentucky State University
Frankfort, KY 40601 USA
kimberly.trosvik@kysu.edu
Fish meal (FM) is considered the most nutritionally-complete protein source in diets for finfish due to its ideal balance of essential
fatty acids, amino acids, vitamins, and minerals. Fish meal’s nutritional profile is also desirable in the livestock and poultry
industries, which increases competition and demand for this resource, making fish meal the most expensive macro-ingredient
of a fish diet. There are numerous attractive protein sources that potentially could replace fish meal in aquaculture diets.
However, these protein sources often do not provide for similar growth in fish when compared to diets with fish meal. It has
been stated that the use of two or more complimentary protein sources may allow for growth results similar to ones found when
fish meal is added to a diet. Soybean meal and yeast are two favorable alternatives to fish meal that have shown some promise
when used in combination for fish meal replacement.
Tilapia are one of the most-cultured fin fish in the world. Organically-fed tilapia may allow producers to enter the rapidlydeveloping
organic sector of the market. The objective of this study was to assess the digestibility and effect of amino acid
supplementation in organic tilapia diets containing organically-certified yeast and soybean meal as a complete protein replacement
for fish meal.
A 6-week feeding trial was performed in a rack recirculating system comprised of 36, 10.0-L tanks stocked with 20, 200mg
fish per tank. Water temperature was maintained at 28 C. Fish were fed three times daily (0800, 1200 and 1600) all they could
consume in thirty minutes. Nine diets were formulated (Table 1) with 4 replicates per diet.
Data will be compared between final weight, feed conversion ratio, protein efficiency ratio, and specific growth rate. Results
will be discussed.
Table 1. Formulation of nine experimental diets fed to Nile tilapia.
Diet
1 2 3 4 5 6 7 8 9
Menhaden FM 20.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
NuPro© 0.0 0.0 0.0 15.0 30.0 45.0 15.0 30.0 45.0
Soybean meal 50.3 84.4 83.9 67.1 51.0 35.7 68.4 51.3 33.8
Lysine 0.0 0.0 0.3 0.0 0.0 0.0 0.4 0.4 0.4
Methionine 0.0 0.0 0.3 0.0 0.0 0.0 0.4 0.3 0.3
Other 29.7 15.6 15.5 17.9 19.0 19.3 15.8 18.0 20.5