Abstract
The goal of the current study was to compare how well Nile tilapia, Oreochromis niloticus, utilized copper (Cu) as bulk and nano sources by evaluating fish growth, body indices, hematological assays, plasma metabolites, immune and anti-oxidative abilities, and intestinal morphometric measurements. The basal diet served as a control, with no Cu added, whereas the experimental diets were formed by adding bulk-Cu and nano-Cu to the basal diet to keep Cu levels at 3 and 6 mg kg-1, respectively, in both Cu sources. Tilapia (9.10 ± 0.014 g) were fed the control diet and four experimental diets for 12 weeks. Results indicated that growth, feed utilization, and body indices demonstrated a substantial improvement (P ≤ 0.05) in tilapia that received a diet containing 3 and 6 Nano-Cu mg kg-1 diet, compared to the performance of fish that received diets containing 3 and 6 Bulk-Cu mg kg-1 diet and the control diet. Villi height, villi width, absorption area of villous (AAV), and mucosal to serosal amplification ratio (MSR) values demonstrated a substantial increase (P ≤ 0.05) in tilapia fed 3 and 6 mg kg-1 Nano-Cu compared to the values observed in fish fed the control and Bulk-Cu supplemented diets. Fish fed Bulk-Cu recorded the highest (P ≤ 0.05) hemoglobin concentration in those fed 6 mg kg-1 compared to 3 mg kg-1. Hematocrit value considerably improved (P ≤ 0.05) by supplementation of Cu, whereas the highest significant value demonstrated in fish provided 6 mg/kg-1 Nano-Cu. A fish-fed diet containing 3 mg kg-1 Nano-Cu revealed the best (P ≤ 0.05) values of plasma albumin, total protein, and globulins. Plasma HDL-C highest concentrations (P ≤ 0.05) were reported in fish fed diet supplemented with 6 mg/kg-1 either Bulk or Nano Cu, whereas values of plasma TG and VLDL-C declined as Cu supplementation level increased either from Bulk or Nano source. Also, the best (P ≤ 0.05) values of CAT and GPX were seen in fish given diet supplemented with 6 Nano-Cu mg/kg-1. Fillets of fish-fed Nano-Cu-supplemented diets showed a marked decline (P ≤ 0.05) in moisture and fat contents, while crude protein, ash, and Cu contents considerably increased in the fillet by dietary supplementation of Nano-Cu at both levels 3 and 6 mg kg-1. In conclusion, the supplemental diets with 3 or 6 Nano-Cu mg/kg-1 enhanced growth, feed utilization, body indices, fillet nutrient composition, hematological assay, plasma metabolites, immune, antioxidant activities, and intestinal morphometry of Nile tilapia.