METABOLIC REQUIREMENTS OF RED DRUM, SCIAENOPS-OCELLATUS, FOR PROTEIN AND ENERGY-BASED ON WEIGHT-GAIN AND BODY-COMPOSITION

Precise formulation of diets that meet but do not greatly exceed nutri tional requirements should assist in lowering feed costs for commercia l aquaculture of red drum, Sciaenops ocellatus, In this study, protein and energy requirements of red drum for maintenance and maximum gain were determined by feeding a diet containing digestible protein (DP) a t 36.5% and 14.2 kJ digestible energy (DE) per gram at various rates f or 8 wk in two separate experiments, Changes in weight and whole-body energy and protein were measured End regressed against protein or ener gy fed using a nonlinear procedure, In the first experiment, juvenile fish [similar to 3.4 g initial body weight (BW)] were either starved o r fed at one of the following g/(100 g BW . d): 0.5, 1, 2, 4, 6, or 8, The second experiment utilized larger red drum (similar to 5.5 g init ial weight), fed 0.75, 1.5, 3, 5, 5.5, 6, 6.5 or 7 g/(100 g BW . d) to confirm and refine results from the first experiment. Based on mainte nance of body weight in both experiments, red drum had a protein maint enance requirement of 1.5 and 2.5 g DP/(kg BW . d) whereas estimates b ased on maintenance of whole-body protein were 0.5 and 2.2 g DP/(kg . BW d), Energy requirements for maintenance of weight and body energy r anged from 58 to 93 and 92 to 97 kJ DE/(kg . BW d), respectively, Prot ein requirements for maximum weight gain and change in body protein ra nged from 20 to 25 g DP/(kg . BW . d), whereas energy requirements for maximum weight gain and whole-body deposition ranged from 776 to 958 and 914 to 985 kJ DE/(kg BW . d), respectively, These requirements for maintenance and maximum gain of red drum should assist in formulation of diets for a variety of desired feeding strategies.