Specific growth rate (% day ⁻¹) of zebrafish (a) larvae and (b) juveniles fed the experimental diets. Boxplots show minimum and maximum (whiskers), first quartile, median, and third quartile (box). ^a–e Different letters indicate statistically significant differences among the experimental groups (p < 0.05).

Percentage of feed ingested after 15 min administration of experimental diets in zebrafish juveniles. Results are expressed as mean + SD (n = 3). ^a–c Different letters indicate statistically significant differences among the experimental groups (p < 0.05).

Example of histomorphology of intestine and liver parenchyma of zebrafish (a–c) larvae and (d–f) juveniles from the present study. (a) Representative section of liver (*) and intestine (arrowhead) of a whole-embedded zebrafish larva fed CTRL diet; (b) details of mucosal folds of intestine from a zebrafish larva fed PG diet (double-headed arrow indicate mucosal folds height); (c) liver parenchyma from a zebrafish larva fed A1⁺ diet; (d) section of intestine (arrowhead) from a zebrafish juvenile fed A2⁺ diet (# indicate perivisceral adipose tissue); (e) details of mucosal folds of intestine from a zebrafish juvenile fed ROT diet (double-headed arrow indicate mucosal folds height); (f) liver parenchyma from a zebrafish juvenile fed A⁻ diet. Scale bars: a = 200 μm; b,c,e,f = 20 μm; d = 100 μm.

Relative mRNA abundance of genes involved in growth analyzed in whole larvae or in liver samples from juveniles. (a) igf1 and (b) mstnb in larvae; (c) igf1 and (d) mstnb in juveniles. Results are expressed as mean + SD (n = 5). ^a,b Different letters denote statistically significant differences among the experimental groups; ns, no significant differences.

Relative mRNA abundance of genes involved in appetite regulation analyzed in whole larvae or in intestine (ghrl), brain (npy), and liver (lepa) samples from juveniles. (a) ghrl, (b) npy, and (c) lepa in larvae; (d) ghrl, (e) npy, and (f) lepa in juveniles. Results are expressed as mean + SD (n = 5). ^a–d Different letters denote statistically significant differences among the experimental groups; ns, no significant differences.

Relative mRNA abundance of genes involved in reward system analyzed in whole larvae or in brain samples from juveniles. (a) drd1b, (b) drd2a, and (c) drd3 in larvae; (d) drd1b, (e) drd2a, and (f) drd3 in juveniles. Results are expressed as mean + SD (n = 5). ^a–e Different letters denote statistically significant differences among the experimental groups; ns, no significant differences.

Relative mRNA abundance of genes involved in immune and stress response analyzed in whole larvae or intestine (immune response: il1b, il10, and litaf) and liver (stress response: nr3c1) samples from juveniles. (a) il1b, (b) il10, (c) litaf, and (d) nr3c1 in larvae; (e) il1b, (f) il10, (g) litaf, and (h) nr3c1 in juveniles. Results are expressed as mean + SD (n = 5). ns, no significant differences.

Total lipid content (g/100 g) of zebrafish juveniles. ^a–f Different letters show statistically significant differences among experimental groups (p < 0.05). Values are reported as mean + SD (n = 3).