(A) Calcein vital staining of fish scales. The mineralized tissue profile can be observed in untreated (CTR) scales or treated with LTG, glucose, and GLU + LTG. Mineralized matrix resorption lacunae are indicated by white arrows. (B) Quantification of mineralized area of the scale (CTR vs. GLU, p < 0.001; GLU + LTG vs. GLU, p < 0.001). p < 0.001 (***).

(A) Histological TRAP activity assay. Enzymatic activity along scale border of CTR scales or treated with LTG, GLU, and GLU + LTG can be visualized by violet staining. (B) Percentage of TRAP-positive scales (CTR vs. GLU, p < 0.001) (GLU + LTG vs. GLU, p < 0.001). (C) TRAP-activity extension calculation among TRAP-positive scales, (CTR vs. GLU, p < 0.001) (GLU + LTG vs. GLU, p < 0.001). (D) Biochemical TRAP assay. Quantification of TRAP activity was performed on same samples with a biochemical assay (CTR vs. GLU, p < 0.001; GLU + LTG vs. GLU, p < 0.001). p < 0.01 (**) and p < 0.001 (***).

(A) Histological ALP activity assay. Enzymatic ALP activity of CTR scales or treated with LTG, GLU, and GLU + LTG can be visualized as blue staining. The areas of fish scale with a reduced ALP activity are evidenced by black arrows. (B) Biochemical ALP assay. Quantification of ALP activity was performed on same samples with a biochemical assay (CTR vs. GLU, p < 0.001) (GLU + LTG vs. GLU, p < 0.01). p < 0.01 (**) and p < 0.001 (***).