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Determines the effects of feeding different sources of brine shrimp nauplii with different fatty acid compositions on the growth, survival and fatty acid composition of striped bass and palmetto bass. High eicosapentaenoic acid percentage in Chinese brine shrimp; Shrimp sources from the San Francisco Bay, California; Great Salt Lake in Utah.

Channel catfish, Ictalurus punctatus, in a quadruplicate flowthrough aquaria for 15 weeks, were fed a semipurified basal diet containing no folic acid or with folic acid levels ranging from 0.2 to 10.0 mg/kg with or without antibiotic. A second study was conducted for 25 weeks under similar conditions but with semipurified diets containing either 20 or 200 mg/kg ascorbic acid and either 0, 0.4, or 4.O.mg/kg folic acid in a factorial design. Mortalities throughout both experiments were monitored and the etiological causes noted. Fish remaining from the second study were overwintered in circular tanks, kept on the same experimental diets, and challenged with Edwardsiella ictaluri after having been on experimental diets for 50 weeks. In both studies, the addition of folk acid to the basal experimental diet resulted in a decreased incidence of columnaris, Flexibacter columnaris. Folic acid concentration in the diet significantly affected mortalities in fish exmrimentallv challenged with E. ictaluri; however, there was significant interaction between the folic acid concentration and the concentration of ascorbic acid. At the lower concentration of ascorbic acid, 4 mg/kg of folic acid was required to reduce mortalities, but at the higher concentration of ascorbic acid, only 0.4 mg/kg folic acid was needed to reduce mortalities below that of the diet without folk acid. Antibody tilers were not affected by folic acid concentration at the lower concentration of ascorbic acid; however at the higher concentration of ascorbic acid, the diets containing 0.4 or 4 mg/kg of folic acid resulted in increased antibody production. [ABSTRACT FROM PUBLISHER]

Demonstrates the importance of dietary folic acid to resistance to columnaris infection in channel catfish in two feeding studies. Effect of folic acid concentration in the diet on mortalities in fish experimentally challenged with Edwardsiella ictaluri.

Young channel catfish (Ictalurus punctatus) with an initial weight of 0.9 ± 0.03 g were fed semipurified diets containing 7% lipids as beef tallow, corn oil, linseed oil, menhaden oil, or a mixture (1:1:1) of menhaden oil, beef tallow, and corn oil at two water temperatures, 17 ± 1°C and 28 ± 0.5°C, for 9 weeks. At the higher temperature, fish fed the menhaden oil and the mixed-oil diets had greater weight gains (P < 0.05) than fish fed the other diets. Weight gains for fish fed beef tallow, corn oil, or linseed oil did not significantly differ (P > 0.05). At the lower water temperature, weight gain was much less, and the only significant difference among treatments was between the fish fed menhaden oil or mixed oil and those fed beef tallow, which gained no weight. The concentration of polyene fatty acids in liver phospholipids was higher at the low temperature than at the high temperature (P < 0.05). The primary n-3 highly unsaturated fatty acid (HUFA) in liver phospholipids of fish fed menhaden oil or the mixed oils was 22:6 n-3, docosahexaenoic acid (DHA). Fish fed corn oil had primarily 20:4 n-6, arachidonic acid (AA), in their phospholipids, and those fed linseed oil had a small amount of 20:5 n-3, eicosapentaeonic acid (EPA), but no DHA in their liver phospholipids. This study indicates that the presence of fish oil, a source of n-3 HUFA, in the diet enhances growth of young channel catfish at optimum and suboptimum temperatures. [ABSTRACT FROM PUBLISHER]

A feeding experiment was conducted in aquaria to evaluate growth, survival, and food consumption by larval striped bass (Morone saxatilis) fed live brine shrimp, shock-frozen brine shrimp, freeze-dried brine shrimp, or a commercial dry diet. The larvae were fed from first feeding through day 19 posthatch. Through day 16 there was no difference in standard length between fish fed the live brine shrimp and those fed the dry diet (P > 0.05), whereas fish fed the other diets were smaller (P < 0.05). At day 19, the striped bass fed the live brine shrimp were larger than those fed all other diets (P < 0.05). Survival was greatest (P < 0.05) for fish consuming live brine shrimp (28.5%), followed by those fed the dry diet (18.0%), freeze-dried brine shrimp (9.8%), and shock-frozen brine shrimp (9.3%). The percentage of fish consuming food was greatest (P < 0.10) for striped bass fed live brine shrimp (85.8%), followed by those fed freeze-dried brine shrimp (38.6%), shock-frozen brine shrimp (38.2%), and the dry diet (32.3%). The reason for the poorer growth and survival of fish fed the nonliving diets may have been the lower rate of food consumption. [ABSTRACT FROM PUBLISHER]

Presents the economic analysis of overwinter feeding regimens for channel catfish in the U.S. Concern of catfish farmers over overwintering; Comparison of three overwintering strategies; Sensitivity analyses on feed conversion ratios, stocking rates and fish selling prices.

A feeding experiment was conducted with two year-groups of channel catfish (Ictalurus punctatus). These groups were fed a 32% protein practical-type diet in 0.04-hectare production ponds for a 145-d growing period. The younger fish were grown from an average size of 20 g to 462 g by their second year at a stocking density of 13,590 fish/hectare, and the older fish were grown from an average size of 594 g to 1,579 g by their third year at a stocking density of 4,942 fish!hectare. Each year-group was fed once daily to satiation in four replicate ponds. Feed conversion ratio (weight of feed fed: weight gain of fish) was significantly lower for second-year fish (1.38) than for third-year fish (1.78). Dressing yield was significantly higher for third-year fish (66.3%) than for second-year fish (60.8%). Second-year fish had lower muscle fat (6.7%) than third-year fish (9.2%). Moisture in the muscle was higher for second-year fish, and muscle protein was not different between the year-groups. Results from this study indicate that second-year channel catfish have advantages over third-year fish in better feed efficiency and lower muscle fat, but third-year fish have higher dressing yield. [ABSTRACT FROM PUBLISHER]