Table 2.

Effects of thiourea, triiodothyronine or both on tilapia juveniles

0 p.p.m.0.1 p.p.b. T310 p.p.b. T30.1 p.p.b. T3 + 300 p.p.m. TU10 p.p.b. T3 + 300 p.p.m. TU
Total length (mm)18.4±1.0a18.1±1.3a19.2±1.2a14.0±0.6b13.9±0.5b
Wet mass (mg)80.1±16.4a76.9±20.7a88.9±21.4a25.2±4.9b24.5±5.1b
Mortality (%)003.707.4
Otolith growth
   Core to TC (μm)191.3±5.6a192.9±4.4a192.2±4.8a189.6±5.7a189.9±5.2a
   TC to edge (μm)111.6±20.5a113.1±20.8a129.9±16.5a45.7±11.8b62.9±10.7b
   Newly deposited DGI13.2±0.4b14.0±0.7ab14.4±0.9a9.0±1.6c10.8±1.6c
  • Fish were immersed in different treatments from 15 to 27 days post-hatching (d.p.h.) and samples were killed for measurement on 28 d.p.h. Data are shown as means ± s.d. (N=22–26). TU, thiourea; T3, triiodothyronine; TC, tetracycline mark; DGI, daily growth increment. Values with different superscript letters are significantly different (P<0.05)