Impact of Nanonutrient Complex on Growth Performance, Feed Efficiency, and Hematobiochemical Profiles in Asian Catfish, <i>Clarias batrachus</i>

Understanding how nanonutrients influence the growth and physiological processes of cultivable fish can boost fish production efficiency with less management, advancing aquaculture toward global food security. In this study, a 60-day feeding trial was conducted to determine the effects of a nanonutrient complex (NNC) on the growth performances and physiology of Asian catfish, <i>Clarias batrachus</i>. Nanoparticles (NPs; Zn, Cu, and Fe) were synthesized from their metallic salts using an established acoustic method and characterized via scanning electron microscopy. The NNC was formulated by mixing zinc NPs (Zn-NPs), copper NPs (Cu-NPs), and iron NPs (Fe-NPs) in a 40:20:40 ratio. In the experiment, a basal diet was supplemented with NNC at concentrations of 0.0 (control), 10, 20, 30, 40, and 50 mg/kg and fed to <i>C. batrachus</i> for 60 days to evaluate growth and physiological parameters (hematology, lipid, and enzyme profiles). The findings indicated that fish administered 30 mg/kg NNC achieved the highest final weight (FW; 25.73 ± 0.41 g), weight gain (WG; 386.67% ± 10.12%), average daily gain (ADG; 0.34 ± 0.01 g/fish/day), specific growth rate (SGR; 2.64 ± 0.03%/day), and enhanced feed conversion ratio (FCR; 1.24 ± 0.03), with statistically significant differences (<i>p</i> < 0.05) relative to the control group. Regression study determined the ideal NNC dosage range to be 30.19-30.26 mg/kg for growth and FCR results. Muscle composition enhanced at this level, with protein and fat content attaining 18.6% ± 0.3% and 6.8% ± 0.2%, respectively. Hematological indices reached their optimum at 30 mg/kg NNC, with red blood cell (RBC) count (3.62 ± 0.21 × 10⁶/mm³), hemoglobin (Hb; 9.83 ± 0.12 g/dL), and hematocrit (Hct; 26.31% ± 0.52%) greatly surpassing those of other treatments. Serum biochemical analysis indicated elevated total protein (4.79 ± 0.05 g/dL), albumin (1.55 ± 0.04 g/dL), and globulin (3.24 ± 0.02 g/dL) at 30 mg/kg, while undesirable elevations in stress markers-cholesterol (224.84 ± 1.10 mg/dL), alanine aminotransferase (ALT; 33.75 ± 0.39 U/L), and aspartate aminotransferase (AST; 40.29 ± 1.17 U/L)-were noted at 50 mg/kg, suggesting potential toxicity at increased dosages. Bioaccumulation of trace elements was most pronounced in the liver, with copper concentrations 11.15% greater than zinc and 1.09% higher than iron, while overall accumulation in the liver surpassed that in muscle and serum by 21.84% and 57.84%, respectively.