James W. Andrews

Effects of dietary copper on channel catfish

Abstract Purified diets with 0, 2, 4, 8, 16 and 32 mg supplemental copper/kg were fed for 16 weeks to channel catfish fingerlings. No signs of deficiency were noted in groups fed a diet without supplemental copper which contained 1.5 mg copper/kg of diet. Reduced growth and feed conversion were noted in fish fed 16 and 32 mg copper/kg. The copper levels in liver were significantly higher in fish fed 32 copper/kg than those fed the unsupplemented diet. Slight anemia was noted in fish fed 32 mg copper/kg. Plasma, erythrocyte and muscle copper levels were not affected by diets containing up to 32 mg copper/kg.

Effects of dietary cholecalciferol and ergocalciferol on catfish

Abstract In separate feeding trials, channel catfish fingerlings were fed 0, 1000, 4000, 8000, 20,000, 50,000, and 0, 500, 1000, 2000, 4000, 8000 I.U./kg diet of cholecalciferol and ergocalciferol for 28 weeks. The supplemental requirement for maximal growth was between 1000 and 4000 I.U. of supplemental cholecalciferol/kg diet. At supplemental levels of 1000 I.U./kg diet or less, the growth responses to ergocalciferol were equal to those obtained from equivalent levels of cholecalciferol. However, at higher supplemental levels of ergocalciferol, the weight gains were significantly less than those obtained from 2000 to 20,000 I.U./kg of cholecalciferol. Weight gains were significantly reduced when 50,000 I.U./kg of cholecalciferol were fed. Vertebrae bone ash values were not affected by dietary vitamin D levels. Reduced weight gains and feed efficiency were the only signs of vitamin D deficiency or hypervitaminosis D.

Some effects of feeding rate on growth, feed conversion and nutrient absorption of channel catfish

Abstract In an 8-week trial, 300-g channel catfish ( Ictalurus punctatus ) were fed at five feeding rates: a control group which was fed at a rate that approximated the ad libitum rate for this size fish, and four groups which were fed at 110, 90, 75 and 50% of the control rate. Significant decreases in growth and feed conversion (feed/gain) rates were obtained in treatments fed 110% of the control rate. Water quality monitoring indicated that this reduction in performance was not due to poorer water quality. Gains were not significantly affected by feeding 90% of the control level, but were reduced in the 75 and 50% treatments. Food efficiencies were improved by reduction of the feeding rate to 90 and 75% of the control level, but were not further improved at the 50% feeding level. Total absorbability and digestible energy values for the test diet were improved by restricting the rate to 90% of the control, but protein absorbability was not affected.

Fingerling American Shad: Effect of Valium, MS-222, and Sodium Chloride on Handling Mortality

Abstract Two experiments were conducted to study the effects of Valium, MS-222, and sodium chloride on the mortality induced by handling and transporting fingerling American shad (Alosa sapidissima). Fish that were given an oral administration of Valium (0.04 mg/kg fish) and transferred without removal from the water (water transfer), showed nearly 100% survival for 24 h in a polyethylene bag without any delayed mortality. The removal offish from the water (air transfer) during handling resulted in heavy scale losses. Oral administration of Valium (0.08 mg/kg fish) did not prevent high mortality (more than 80%) when scale losses were excessive. Addition of sodium chloride to the transporting water (1%) showed a significant beneficial effect on survival for up to 4 h; however, it was not effective in preventing mortality caused by severe scale losses. MS-222 at a concentration of only 10 mg/L proved to be toxic to shad. The results of these experiments suggest that fingerling American shad can be successfu...

Chemical composition of effluent from high density culture of channel catfish

Production rates of metabolic wastes by channel catfish (Ictalurus punctutas) were estimated by analyzing effluents from high density culture of 940 g and 60 g catfish. Results were integrated over a 24 h steady-state period in which normal feeding activities were maintained and were expressed as g day−1kg−1 fish and g day−1 kg−1 feed consumed. When expressed on a unit fish weight basis, production rates were greater for 60 g than for 940 g catfish. However, when expressed on a feed consumption basis, production rates of most catabolic products were approximately equal for both size fish. Average values (g day−1 kg−1 feed) were as follows: total N, 67; ammonia N, 20; nitrate-nitrite N, 20; 5-day BOD, 98; total solids, 180; total P, 15; total K, 18. Filtered solids from effluent contained 5% nitrogen, 1.6% phosphorus and .13%. potassium. Diurnal variation in production rates were noted with solid production reaching a maximum after each feeding and BOD, NH3 and nitrate reaching a maximum only in the afternoon.

Dietary Studies with American Shad Fry

Abstract Studies were conducted to evaluate foods for fry of American shad (Alosa sapidissima) in earthen ponds and outdoor tanks. Fry grew rapidly (more than 100 mg in 4 weeks) in both ponds and tanks when suitable food was available. Live Daphnia magna and D. pulex were excellent food sources. A commercial fry feed for trout and a mixed culture of rotifers and wild Moina sp. also produced acceptable growth. Despite the fact that a considerable amount of phytoplankton was found in the stomach contents, phytoplankton alone did not appear to be a suitable diet for shad fry.