A Preliminary Study on Effects of Different Dietary Selenium (Se) Levels on Growth Performance and Toxicity in Juvenile Black Seabream, Acathopagrus schlegeli (Bleeker)

摘要

This preliminary feeding trial was conducted to study the effects of different dietary selenium (Se) levels on growth performance and toxicity in juvenile black seabream, Acanthopagrus schlegeli (Bleeker). Fish averaging 7.0 +/- 0.1 g (mean +/- SD) were fed one of the five semi-purified diets containing 0.21, 0.30, 0.52, 1.29 and 12.3 mg sodium selenite (Na,SeO3)/kg diet (Se 0.21, Se 0.30, Se 0.52, Se 1.29 or Se 12.3) for 15 weeks. After the feeding trial, weight gain (WG), feed efficiency (FE). specific growth rate (SGR) and protein efficiency ratio (PER) of fish fed Se 0.21, Se 0.30, Se 0.52 and Se 1.29 diets were not significantly different. however fish fed Se 12.3 diet showed significantly lower WG, FE, SGR and PER than those of fish fed the other diets (p<0.05). Fish fed Se 0.21, Se 0.30, Se 0.52, Se 1.29 and Se 12.3 diets showed no significant differences in hematocrit (PCV). hemoglobin (Hb) and red blood cells (RBC), however fish fed Se 12.3 diet showed lower values of PCV, Hb and RBC than those of fish fed the other diets. Histopathological lesions such as tubular necrosis and polycystic dilation of tubules in the kidney tissues were observed in fish fed Se 12.3 diet. Se was accumulated in a dose-dependent manner in the liver, kidney muscle and gill tissues. Based on the results of this preliminary feeding trial, a dietary Se level of 0.21 mg Na2SeO3/kg diet could be optimal for proper growth performances. and a dietary Se level of 12.3 mg Na2SeO3/kg diet may ultimately be toxic to juvenile black seabream, Acanthopagrus schlegeli.