The Company of Biologists

Table 2.

Effects of thiourea, triiodothyronine or both on tilapia juveniles

	0 p.p.m.	0.1 p.p.b. T₃	10 p.p.b. T₃	0.1 p.p.b. T₃ + 300 p.p.m. TU	10 p.p.b. T₃ + 300 p.p.m. TU
Total length (mm)	18.4±1.0^a	18.1±1.3^a	19.2±1.2^a	14.0±0.6^b	13.9±0.5^b
Wet mass (mg)	80.1±16.4^a	76.9±20.7^a	88.9±21.4^a	25.2±4.9^b	24.5±5.1^b
Mortality (%)	0	0	3.7	0	7.4
Otolith growth
Core to TC (μm)	191.3±5.6^a	192.9±4.4^a	192.2±4.8^a	189.6±5.7^a	189.9±5.2^a
TC to edge (μm)	111.6±20.5^a	113.1±20.8^a	129.9±16.5^a	45.7±11.8^b	62.9±10.7^b
Newly deposited DGI	13.2±0.4^b	14.0±0.7^ab	14.4±0.9^a	9.0±1.6^c	10.8±1.6^c

	0 p.p.m.	0.1 p.p.b. T₃	10 p.p.b. T₃	0.1 p.p.b. T₃ + 300 p.p.m. TU	10 p.p.b. T₃ + 300 p.p.m. TU
Total length (mm)	18.4±1.0^a	18.1±1.3^a	19.2±1.2^a	14.0±0.6^b	13.9±0.5^b
Wet mass (mg)	80.1±16.4^a	76.9±20.7^a	88.9±21.4^a	25.2±4.9^b	24.5±5.1^b
Mortality (%)	0	0	3.7	0	7.4
Otolith growth
Core to TC (μm)	191.3±5.6^a	192.9±4.4^a	192.2±4.8^a	189.6±5.7^a	189.9±5.2^a
TC to edge (μm)	111.6±20.5^a	113.1±20.8^a	129.9±16.5^a	45.7±11.8^b	62.9±10.7^b
Newly deposited DGI	13.2±0.4^b	14.0±0.7^ab	14.4±0.9^a	9.0±1.6^c	10.8±1.6^c

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)

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