This study aimed to evaluate the effects of different dietary zinc sources on growth performance, tissue zinc deposition, and intestinal morphology of juvenile rainbow trout (Oncorhynchus mykiss) in a 60-day feeding trial. A total of 260 fish, ±30 g were randomly distributed into 20 tanks of 70 L (13 fish/tank) in a closed RAS. Water temperature was maintained at 14–17 °C and dissolved oxygen above 6.0 mg/L. A trial design of five dietary treatments and four replicates were used and only differing by zinc source: T1 control (inorganic Zn) and three organic chelation technologies T2 (Di & Tri peptides-Zn; Olmix), T3 (Methionine hydroxy analogue-Zn), T4 (Methionine-Zn), and T5 (Glycine-Zn). Total dietary zinc was standardized to 250 mg Zn/kg feed and analytically verified at Eurofins international laboratory (ranging from 248.6–267.4 mg/kg). At day 60, growth performance was recorded and 6 fish per treatment were sampled for blood 1 h post-feeding, gills, skin and liver for Zn quantification, and midgut segment for villi and absorptive area morphometry. Data were analyzed using one-way ANOVA followed by Tukey's test (p<0.10) or Kruskal–Wallis when needed by SigmaPlot 11.0. Growth performance significant differences were observed. Final fish weight were the highest in fish fed T2 followed by T3, T4, T5 and least was T1 (p=0.095) which also reflected higher biomass. Zinc concentrations in plasma, erythrocytes, total blood, and liver remained stable across treatments, indicating no statistically significant effect of zinc source on these tissues and organs. Gut absorptive area (mm2) were higher +17% in all organic sources compared to control group (p<0.001). Skin zinc deposition showed a clear separation between inorganic control and the organic sources which avareged +21% higher deposition (p=0.021). The most interesting findings were in the Zn quantification in the gills from which differences among the chelation technology were more clearly observed. Zn bioavailability in the gills in fish fed the T2 and T4 were significantly higher by +43% and +37% than control and other treatments meanwhile T3 and T4 did not differ from control group (p=0.016). As a conclusion, the di and tri peptides-based Zn (T2) showed the most consistent response followed by Methionine-based (T4), combining the highest final weight with increased Zn deposition in skin and gills, supporting higher functional bioavailability. These results indicate that Zn deposition in the gills could be useful as sensitive endpoints to differenciate chelation technologies in rainbow trout fed diets standardized for total Zn levels.