This feeding trial was carried out to evaluate the effects of different dietary
cadmium levels on growth and tissue
cadmium content in juvenile parrotfish, Oplegnathus fasciatus, using
cadmium chloride (CdCl2) as the
cadmium source. Fifteen fish averaging 5.5±0.06 g (mean±SD) were randomly distributed into each of twenty one rectangular fiber tanks of 30 L capacity. Each tank was then randomly assigned to one of three replicates of seven diets containing 0.30 (C0), 21.0 (
C21), 40.7 (C41), 83.5 (C83), 162 (C162), 1,387 (C1,387) and 2,743 (C2,743) mg
cadmium/kg diet. At the end of sixteen weeks of feeding trial,
weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of fish fed
C21 were significantly higher than those of fish fed C83, C162, C1,387 and C2,743 (p<0.05).
Weight gain, SGR and FE of fish fed C0,
C21 and C41 were significantly higher than those of fish fed C162, C1,387 and C2,743.
Protein efficiency ratio of fish fed C0,
C21 and C41 were significantly higher than those of fish fed C1,387 and C2,743. Average survival of fish fed C0,
C21, C41 and C162 were significantly higher than that of fish fed C2,743. Tissue
cadmium concentrations increased with
cadmium content of diets.
Cadmium accumulated the most in liver, followed by gill and then muscle. Muscle, gill and liver
cadmium concentrations of fish fed C0,
C21, C41 and C83 were significantly lower than those of fish fed C162, C1,387 and C2,743. Based on the ANOVA results of growth performance and tissue
cadmium concentrations the safe dietary
cadmium level could be lower than 40.7 mg Cd/kg diet while the toxic level could be higher than 162 mg Cd/kg diet.