Effect of different dietary energy levels on growth index and liver histology of Yellowfin seabream, Acnthopagrus latus

An eight week feeding trial was conducted to determine the energy requirement of growth in yellowfin sea bream (Acanthopagrus latus) fed with diet containing three energy levels (20, 22 and 24 kj g-1 crude) and wet diet (Trash fish). Triplicate groups of 20 fish (12±2. 1 initial weight) were each stocked in 300-L fiberglass tanks and fed twice a day to apparent satiation. Survival rate and body weight gain (BWG) were independent of the dietary treatments. Formulated diet and wet diet significantly affected condition factor (K) and food conversion ratio (FCR). K increased with the increase of energy from 20 to 24 kJ gr-1 but FCR decreased with increasing energy levels. Viscera somatic index (VSI), hepatosomatic index and intraperitoneal fat ratio (IPF) were highest in formulated diet. Moisture and ash contents decreased with increasing energy levels in diet, but carcass lipid content, gross energy retention (GER), protein retention (PR) increased with increasing dietary energy. GER was significantly affected by diets with high energy (24 and 22 kJ/gr diet) or low energy (20Kj/gr and wet diet) contents. The liver droplet area (LDA) was the highest in fish fed high energy diet. The results indicated that the optimum dietary energy levels and the best P/E, for the best growth performance of juvenile yellow fin sea bream were 21.9kJ in gr. diet 25 g kJ-1, respectively.