EFFECTS OF INORGANIC AND ORGANIC DIETARY COPPER SUPPLEMENTATION ON GROWTH PERFORMANCE AND TISSUE COMPOSITION OF JUVENILE RED DRUM Sciaenops ocellatus

Copper (Cu) is an essential trace element for fish. A commonly copper source used in animal feed is copper sulfate (CuSO4) that has poor bioavailability due the antagonism between this mineral and other nutrients, thus impairing its uptake and being excreted into the environment. The high price of fish meal has led to higher inclusion of plant proteins in aquaculture feeds, which can affect absorption of inorganic copper, because of the presence of anti-nutrients such as phytic acid. On the other hand, organic minerals have higher bioavailability, because they are chelated with peptides, amino acids and other organic compounds that protect the minerals from reactions in the gastrointestinal tract. Therefore, the aim of this study was to investigate the effects of dietary supplementation of inorganic and organic copper compounds for red drum.

Red drum muscle, wheat gluten, and crystalline amino acid were used as protein sources to ensure that the basal diet had minimum level of natural copper. The diet was formulated to contain 35% crude protein and used as a negative control, and either copper sulfate or copper-ethanolamine complex were added to the basal diet at 5, 10, 20 mg Cu/kg dry diet. The feeding trial was conducted in a recirculation system in which 17 fish (initial weight of ~6 g/fish) were assigned to 110-L glass aquaria. All treatments were fed to triplicate aquaria and fish fed twice daily to approach apparent satiation for 7 weeks.

The trial is currently being conducted and growth performance and survival are presented on table 1. Further results in regards to final weight gain, feed efficiency and additional analysis will be reported soon.