1. Introduction
Although a substantial amount of research has been conducted on the identification of Ž
. feeding stimulants FS for fish, there are only a few cases where FS have been applied
to practically formulated diets. FS can be of immediate practical importance in enhanc- .
Ž ing the acceptance of: 1 artificial feeds by first feeding larvae and fry Metailler et al.,
1983; Person-Le Ruyet et al., 1983; Hughes, 1991; Kamstra and Heinsbroek, 1991; .
. Heinsbroek and Kreuger, 1992 and 2 diets containing low cost feedstuffs of low
Ž .
palatability Takeda and Takii, 1992 . Currently, the diets used for feeding striped bass contain high levels of animal protein
Ž .
in general and fish meal in particular Gatlin, 1997 . Such diets are not only costly, but contribute to the eutrophication of receiving waters because of excessively high levels of
Ž .
phosphorus excreted from the fish Ketola and Harland, 1993 . Moreover, future
supplies of fish meal are expected to decrease, or at best remain constant, while Ž
aquaculture production is increasing at a steady rate Food and Agriculture Organization, .
1999 . The three factors mentioned above necessitate the identification of new protein sources to partially or totally replace fish meal in diets for cultured fish.
It has already been suggested that a means to reduce the cost of diets for carnivorous Ž
fish is to use plant feedstuffs as replacements of expensive animal proteins Cho et al., .
1974; Tacon, 1994 . A major obstacle in using high levels of plant feedstuffs, besides nutrient composition and availability, is poor acceptance of the diets. A decrease in feed
Ž intake has been reported with inclusion of soybean meal in diets for rainbow trout Cho
. Ž
. Ž
et al., 1974 , red drum Reigh and Ellis, 1992 , channel catfish Mohsen and Lovell, .
Ž .
Ž .
1990 and largemouth bass Kubitza et al., 1997 . In addition, Davis et al. 1995 reported that soy protein did not have acceptable palatability properties for red drum. In
Ž .
a subsequent study, McGoogan and Gatlin 1997 reported that glycine supplementation enhanced growth and feed efficiency of red drum fed soybean meal-based diets. Gomes
Ž .
et al. 1997 showed that both soy protein concentrate-based diets, as well as corn gluten meal-based diets, reduced feed intake of European sea bass. Furthermore, it was
demonstrated in the same study that addition of an amino acid attractant mixture improved feed intake, growth and feed efficiency of fish fed the soy protein
concentrate-based diets.
Ž .
FS for striped bass have been recently identified Papatryphon and Soares, in press . Furthermore, it was demonstrated that maximum feeding stimulation was accomplished
with a mixture of
L
-alanine,
L
-serine, inosine-5
X
-monophosphate and betaine, which is in agreement with previous studies suggesting that mixtures are more effective than
Ž .
individual compounds Carr and Derby, 1986 . The advantages of using these com- pounds in practical applications, however, remains to be shown.
The purpose of this study was to assess the effects of a previously identified FS mixture on growth performance of striped bass fed-a-plant feedstuff-based diet.
2. Materials and methods
Kategori