EFFECTS OF FEEDING RATES ON GROWTH, BODY-COMPOSITION AND NUTRIENT METABOLISM IN STRIPED BASS (MORONE-SAXATILIS) FINGERLINGS

A 12-week experiment was conducted to determine the effects of feeding rates on growth, morphology, body composition, and nutrient partition ing and metabolism in striped bass fingerlings with an average initial body weight of 38 g. The striped bass fingerlings were fed a commerci al salmonid feed at different feeding rates from 0.5 to 4.0% (with 0.5 % increments) of body weight per day (BW/day) at 19-degrees-C. The fee d was dispensed continuously using automatic feeders and each feeding rate was administered in triplicate to groups of 15 striped bass finge rlings. Growth rate as measured by the percent body weight increase wa s significantly (P<0.05) increased when the feeding rate was increased from 0.5 to 1.5% BW/day, and it reached a plateau with feeding rate o f 1.5% BW/day. Feed efficiency did not show significant difference bet ween fish fed 0.5 and 1.0% BW/day, but decreased steadily thereafter w ith feeding rate increased from 1.0 to 4.0% BW/day. Condition factor, hepato- and viscerosomatic indices, whole-body lipid content, and visc era protein, lipid and ash contents were significantly (P<0.05) increa sed, whereas carcass to body weight ratio, and whole-body and visceral moisture contents were decreased when the feeding rate was increased from 0.5 to 1.0% BW/day. Liver soluble protein and glycogen concentrat ions, and glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydr ogenase, malic enzyme and isocitrate dehydrogenase activities were als o significantly increased when feeding rate was increased from 0.5 to 1.0% BW/day. Mortality, carcass composition, whole body protein and as h contents, plasma glucose, protein, and triacylglycerol concentration s were not significantly different in striped bass fed at different fe eding rates. Based on the growth and feed efficiency data, optimum fee ding rate for striped bass fingerlings raised at 19-degrees-C was betw een 1.0 and 1.5% BW/day.