Table 4.

Effects of thiourea, triiodothyronine, or both on tilapia larvae

Larvae0 p.p.m.25 p.p.b. T3300 p.p.m. TU25 p.p.b. T3 + 300 p.p.m. TU
Total length (mm)11.0±1.1a11.0±0.9a10.8±0.7a10.9±0.6a
Wet mass (mg)14.5±4.1a14.6±4.9a12.4±2.9a12.6±1.9a
Mortality (%)406.735.556.8
Otolith growth
   TC to edge (μm)156.0±18.8b171.7±18.8a147.9±10.6b156.1±13.5b
   Newly deposited DGI14.4±1.3a15.0±1.0a13.8±0.5a
T3 content (ng g–1)1.4±0.4b4.8±0.9a0.8±0.3b
  • Fish were immersed in different treatments from 4 to 16 days post-hatching (d.p.h.) and were killed for measurement on 17 d.p.h. Data are shown as means± s.d. (N=13–20). TU, thiourea; T3, triiodothyronine; TC, tetracycline mark; DGI, daily growth increment. Values with different superscript letters are significantly different (P<0.05)