EVALUATION OF STARTER DIETS IN RAINBOW TROUT Oncorhynchus mykiss THAT DO NOT CONTAIN FISHMEAL OR FISH OIL  

Vaun Cummins*, Alex Tsappis and Keith Filer
 
 Alltech, Inc
 3031 Catnip Hill Pike
 Nicholasville, KY 40356

The global production of fishmeal and fishoil has averaged 6.5 and 1.3 milion metric tons over the past 20 years. The percentage of fish meal and oil in aquaculture diets has been decreasing since the mid 1990's but the percentage of annual global production consumed by aquaculture diets has been increasing.  About 45% of the fish meal used in aquafeeds is used in carnivorous aquafeeds such as salmon, trout, sea bass and sea bream. Continued growth of the aquaculture industry is unsustainable at the current use rates.  A study was conducted to evaluate four diets that were formulated without the use of fishmeal or fish oil.  Three diets (1-3) contained a combination of plant and yeast proteins to obtain the 49% protein level required for the starter diet and algae and plant oils to meet the 15% fat level.  The fourth diet contained poultry meal as well as plant and yeast proteins.

A 12- week feeding trial was conducted in 20 gallon glass aquariums set up as a recirculating aquaculture system with Rainbow trout fry.  Water temperature was maintained at 18°C with a chiller containing a drop in coil in a 250 gallon sump.  A total of 450 Rainbow trout were divided into 15 tanks, 30 per tank.  Each tank was fed one of five marine starter diets three times per day at a rate of 10% of the total fish weight in the tank.  The control diet was a commercial starter diet and four were marine starter diets produced by Alltech .  Fish were weighed at the beginning and end of the trial.  Weight gain, specific growth rate (SGR) and feed conversion ratio (FCR) were calculated.

After the 12 week feeding study the fish fed the commercial diet had the largest final average weight gain and SGR but no statistical differences were determined (p>0.05).  The fish fed the commercial diet had the lowest FCR numerically (p>0.05).