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

EFFECTS OF PREBIOTICS ON NUTRIENT DIGESTIBILITY OF A SOYBEAN- MEAL-
BASED DIET BY GOLDFISH Carassius auratus
Thiago Raggi*, Gary Burr, Brian Ray, Alejandro Buentello and Delbert Gatlin III
Department of Wildlife and Fisheries Sciences
Texas A&M University
College Station, Texas 77843 USA
thiago_82@tamu.edu
A combination of handling stress and suboptimal environmental conditions can result in high mortality on baitfish production.
Different dietary supplements may potentially reduce these losses by increasing immunological response, resistance to disease and
handling stress. Prebiotic compounds comprise one such group of supplements and are defined as non-viable food ingredients that
are selectively metabolized to favor beneficial intestinal bacteria, which may confer various desirable effects including enhanced
disease resistance and nutrient availability to the host organism. Such effects have been observed in some fish species such as red drum
(Sciaenopos ocellatus) and hybrid striped bass ( Morone chrysops x M. saxatilis) as well as golden shiner (Notemogonus crysoleucas).
This study examined the effects of four prebiotics on digestibility of soybean-meal-based diets. The four prebiotics were
GroBiotic ® -A (consisting of a mixture of partially autolyzed brewers yeast, dairy ingredient components and dried fermentation
products), mannanoligosaccharide (MOS), galactooligosaccharide (GOS), and fructooligosaccharide (FOS), each added to a
basal diet at 1% by weight. The diets were formulated so that 50% of the protein was provided by soybean meal and the other
50% was from menhaden fishmeal. Chromic oxide was added to the diets at 1% as an inert marker. Each diet was fed to adult
goldfish in duplicate 110-L aquaria for a total of 8 weeks, and manually stripped to obtain fecal material approximately 10 hours
after feeding on four different occasions. The dried fecal material from each aquarium was pooled over time and analyzed for
protein, lipid, organic matter and chromium in order to compute coefficients of digestibility. Analyses are currently being conducted.
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