Effects of thiourea, triiodothyronine, or both on tilapia larvae
| Larvae . | 0 p.p.m. . | 25 p.p.b. T3 . | 300 p.p.m. TU . | 25 p.p.b. T3 + 300 p.p.m. TU . |
|---|---|---|---|---|
| Total length (mm) | 11.0±1.1a | 11.0±0.9a | 10.8±0.7a | 10.9±0.6a |
| Wet mass (mg) | 14.5±4.1a | 14.6±4.9a | 12.4±2.9a | 12.6±1.9a |
| Mortality (%) | 40 | 6.7 | 35.5 | 56.8 |
| Otolith growth | ||||
| TC to edge (μm) | 156.0±18.8b | 171.7±18.8a | 147.9±10.6b | 156.1±13.5b |
| Newly deposited DGI | 14.4±1.3a | 15.0±1.0a | 13.8±0.5a | – |
| T3 content (ng g–1) | 1.4±0.4b | 4.8±0.9a | 0.8±0.3b | – |
| Larvae . | 0 p.p.m. . | 25 p.p.b. T3 . | 300 p.p.m. TU . | 25 p.p.b. T3 + 300 p.p.m. TU . |
|---|---|---|---|---|
| Total length (mm) | 11.0±1.1a | 11.0±0.9a | 10.8±0.7a | 10.9±0.6a |
| Wet mass (mg) | 14.5±4.1a | 14.6±4.9a | 12.4±2.9a | 12.6±1.9a |
| Mortality (%) | 40 | 6.7 | 35.5 | 56.8 |
| Otolith growth | ||||
| TC to edge (μm) | 156.0±18.8b | 171.7±18.8a | 147.9±10.6b | 156.1±13.5b |
| Newly deposited DGI | 14.4±1.3a | 15.0±1.0a | 13.8±0.5a | – |
| T3 content (ng g–1) | 1.4±0.4b | 4.8±0.9a | 0.8±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)