Evaluation of Gross Protein/Energy Ratios for Adult Florida Pompano, Trachinotus carolinus, Fed Practical Diets, in Relation to Growth, Feed Utilization, and Nitrogen Retention

Florida pompano (Trachinotus carolinus) is a strong candidate for aquaculture production growth in the United States. Demonstrated through research, the species meets many of the criteria for species selection. Research is needed to complete our knowledge of the nutritional requirements at different ages in order to develop cost-effective and environmentally-friendly diets. Our goal was to examine the nutritional requirements in terms of protein and energy for market size fish. Six diets were formulated to be isoenergetic (Gross energy GE= 21 kJ/g). The formulated GP/GE ratios were 18, 19, 21, 22, 23, and 25 g/MJ. Fish average weight was 260.8±21g at the start of the experiment. The pompano were randomly distributed into a flow-through system consisting of 18, 1,000-l conical tanks, at a stocking biomass of 3.0 kg/ m3 per tank. Fish were hand-fed the diets once daily, for 10 minutes or until apparent satiation for 88 days, harvested at 30, 60, and 88 days. The high survival (100%) and good overall health condition of the fish during the entire trial demonstrates the absence of any nutrient deficiency. Results indicated that with an increase in size and age the optimal GP/GE decreased, from 21-22 g/MJ at 382g (first harvest), to 19-21 g/MJ at 486g (second harvest), ending at 19 g/MJ at 577g (third harvest); following a similar trend as reported in literature. Nitrogen retention also decreased with an increasing ratio, with 25 g/MJ displaying the lowest retention. There were no significant differences in either visceralsomatic or hepatosomatic indices