Growth, faecal production, nitrogenous excretion and energy budget of juvenile yellow grouper (Epinephelus awoara) relative to ration level
2007
Sun, L. | Chen, H. | Huang, L.
Growth, faecal production, nitrogenous excretion and energy budget of juvenile yellow grouper (initial body weight 5.5 g or so) at various ration levels (starvation, 0.5%, 1% and 2% of initial body weight per day, and satiation) were investigated in this study. Faecal production (f, mg g-1 d-1) and nitrogenous excretion (u, mg g-1 d-1) increased markedly with increased ration level (RL, % per day), described as f = 0.483RL + 0.112 for faecal production and u = 0.218RL + 0.219 for nitrogenous excretion, respectively. Feed absorption efficiency (FAE, %) increased as ration increased with ranges of 91.4-94.0%, 95.6-97.3% and 96.5-97.6% for FAE(d), FAE(p) and FAE(e), respectively, but all of the variations were small. Relationships between specific growth rate in wet weight (SGR(w), % per day), dry weight (SGR(d), % per day), protein (SGR(p), % per day), energy (SGR(e), % per day) and ration level (RL, % per day) were linear and described as simple equations SGR(w) = 0.738RL-0.764, SGR(d) = 0.871RL-0.928, SGR(p) = 0.904RL-0.966 and SGR(e) = 1.038RL-1.060. Feed conversion efficiency in wet weight (FCE(w), %), dry weight (FCE(d), %), protein (FCE(p), %) and energy (FCE(e), %) all increased as ration increased and maximized at ad libitum ration level. Energy budgets of juvenile Epinephelus awoara at satiation ration level was: 100C = 2F + 4U + 75R + 19G or 100A = 80R + 20G, where C is food energy, A is assimilated energy, F is faeces energy, U is excretion energy, R is metabolism energy and G is growth energy.
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