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

THE EFFECTS OF SOYBEAN OIL, FLAXSEED OIL AND A DAIRY-YEAST PREBIOTIC ON
THE GROWTH AND HEALTH OF CHANNEL CATFISH Ictalurus punctatus FINGERLINGS
AT LOW TEMPERATURE
Miles Thompson* and Rebecca Lochmann
Aquaculture and Fisheries Research Center
University of Arkansas at Pine Bluff
Pine Bluff, AR 71601 USA
mthompson@uaex.edu
Winter-feeding is a historically controversial and poorly understood aspect of commercial catfish production. Catfish fingerlings
fed a standard diet during mild winter periods, when water temperatures exceed 12.7 °C, tend to maintain body weight or
may even grow slightly. Since the catfish immune response is closely linked to both temperature and dietary lipid, varying the
lipid composition of the diet (via source or level) during winter-feeding schedules may have beneficial results on both growth
and overall health. The addition of functional feed additives during winter-feeding regimes may further enhance disease resistance
or growth of catfish fingerlings.
A 12-week trial was conducted using channel catfish
fingerlings (initial mean weight of 61.4 g/fish ± 1.5 g SD)
maintained at a temperature of 16°C in three separate
recirculating systems, each consisting of four 1140-L
tanks. Each diet was made using a commercially available
32%- protein pelleted basal diet, ground to 1mm and repelleted
into a sinking feed with the addition of 2% soybean
oil (control - SBO), 2% flaxseed oil (FLAX), or 2% soybean
oil and 2% dairy-yeast prebiotic (PREB). Fish were
fed once daily to apparent satiation. Feed consumption,
water temperatures and mortalities were recorded daily.
Fifty-fish sub-samples were weighed every three weeks to
monitor growth and adjust the feed rate. Nine-week results
are shown in Figure 1.
At 12 weeks, fish will be maintained on the diets for an
additional two weeks. Individual fish from each tank will
be used for health assays (alternate complement activity,
lysozyme activity, hematocrit and hemoglobin), hepatosomatic
index, and proximate and fatty acid analysis. Final
results will be presented at the meeting.
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