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

Seunghyung Lee,Sungchul C Bai,Jun-Ho Lee

doi:10.5713/ajas.2008.80285

Abstract

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 2 SeO 3 )/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 Na 2 SeO 3 /kg diet could be optimal for proper growth performances, and a dietary Se level of 12.3 mg Na 2 SeO 3 /kg diet may ultimately be toxic to juvenile black seabream, Acanthopagrus schlegeli.

Highlights

Selenium (Se) is the trace mineral which is a component of the enzyme glutathione peroxidase (GPx., EC 1.11.1.9) (Rotruck et al, 1973)
Juvenile black seabream exposed to dietary concentrations ranging between 0.21 and 12.3 mg Na2SeO3/kg diet for 15 weeks showed no significant difference in survival rate
Gatlin and Wilson (1984) showed that channel catfish, Ictalurus punctatus fed diets containing different supplemental Se levels as 0.2, 0.3, 0.4, 0.5, 1.0 and 5.0 mg Na2SeO3/kg diet for 15 weeks showed no significant differences in weight gain (WG) and feed efficiency (FE), a supplemental Se level of 15 mg Na2SeO3/kg diet caused a reduced growth response which indicated Se toxicity in catfish

Summary

INTRODUCTION

Selenium (Se) is the trace mineral which is a component of the enzyme glutathione peroxidase (GPx., EC 1.11.1.9) (Rotruck et al, 1973). The experimental diets were fed to triplicate groups of fish at a fixed rate of 2-2.5% (2.5% of wet body weight in the Proximate analysis (% of dry matter basis) beginning and 2.0% at the end of the feeding trial) per day Moisture Crude protein Crude lipid Crude ash Se (mg/kg). Sample collection and analyses At the end of the feeding trial, all of the fish were weighed and counted for calculation of weight gain, feed efficiency, specific growth rate, protein efficiency ratio and commercially important aquaculture species, and the need survival rate. Three individual fish randomly selected per aquarium by the this preliminary study was carried out to microhematocrit method (Brown, 1980), and hemoglobin investigate the effects of different dietary Se levels on was measured with the same fish by the cyangrowth performance and toxicity in juvenile black seabream, methemoglobin procedure using Drabkin’s solution

MATERIALS AND METHODS

Pooled standard error of mean

RESULTS AND DISCUSSION