Fig. 2

Defective swim bladder inflation and retarded growth of cgα-deficient fish rescued by exogenous thyroxine (T4) supplement A: Schematic of rearing timeline and early T4 administration treatment. Fertilized eggs were reared in egg water containing T4 from 0 to 3 dpf, and in system water containing T4 from 4 to 16 dpf. B–D: Gross appearance of fish at 16 dpf, including control (B), cgα-deficient (C), and cgα-deficient fish administered T4 (D). Black arrow indicates inflated anterior swim bladder of control (B) and cgα-deficient fish administered T4 (D), white arrow indicates undeveloped anterior swim bladder of cgα-deficient fish (C). E: Ratio of anterior swim bladder inflation in control, cgα-deficient, and cgα-deficient fish administered T4 at 16 dpf. F: Schematic of rearing timeline and late T4 administration treatment. Fish were reared in system water containing T4 from 30 to 44 dpf. G–I: Gross appearance of fish at 44 dpf, including control fingerlings (G), cgα-deficient fingerlings (H), and cgα-deficient fingerlings administered T4 (I). J, K: Body weight (J) and length (K) of control, cgα-deficient, and cgα-deficient fingerlings administered T4 at 44 dpf. dpf, days post-fertilization; T4, thyroxine. Different letters in bar chart represent significant differences.