Effects of Dietary Iodine Supplementation Periods on Growth Performance, Carcass Composition and Iodine Content in Flesh of Hybrid Clarias Catfish

Abstract

The objective of this experiment was to study the effects of different periods for dietary potassium iodate (KIO₃) supplementation (30 mg/kg feed) on growth performance, carcass composition and iodine content in fillet of hybrid Clarias catfish. Eight hundred hybrid catfish with average weights of 33 g/fish were divided into four groups with four replications and randomly assigned to different treatments: group 1 (control), fish were fed with commercial floating pellet feed without iodine supplementation for 120 days. For group 2, 3 and 4, fish were fed with iodine supplemented diet 60, 30 and 15 days prior to the end of the experiment, respectively. The experimental design was completely randomized design (CRD). The results showed that there were no differences in growth performance and carcass composition of fish among groups (P > 0.05). However, fish fed iodine supplemented diet 60, 30 and 15 days prior to the end of the experiment had higher levels of iodine contents in fillet compared with fish fed commercial diet without KIO₃ supplementation (P < 0.05). Providing iodine supplemented diet for 15 days prior to the end of the experiment is optimal for increasing iodine level in catfish flesh without extra cost of feed per gain.