Proximate body composition, elemental concentration and enzymatic activity analysis of Catla catla exposed to the nanoparticle (CuO-NPs) and Vitamin C

Aquaculture plays a vital role in global food production, providing a significant source of protein and livelihood for millions of people worldwide. The toxicity of copper oxide nanoparticle (CuO-NPs) can severely impact the health and productivity of farmed fish species, such as Catla catla . This research aims to evaluate the effectiveness of Vitamin C in protecting C. catla from the harmful effects of CuO-NPs, thereby contributing to sustainable aquaculture practices. Fish exposed to various levels of CuO-NPs and Vitamin C exhibited varying degrees of responses for proximate body composition, elemental concentration, and digestive enzymes. A total of 540 samples of C. catla were collected from Bahawalpur Fish Hatchery, Punjab, Pakistan. CuO-NPs synthesized by green synthesis from neem extracts ( Azadirachta indica ) added in fish feed and exposed for 90 days in glass aquaria (Triplicate) with five experimental groups as T-I (2 mg/kg CuO-NPs), T-II (4 mg/kg CuO-NPs), T-III (2 mg/kg CuO-NPs with 250 mg/kg Vitamin C), T-IV (4 mg/kg CuO-NPs with 250 mg/kg Vitamin C) and T-V (250 mg/kg Vitamin C) and one control group (T-O). Results indicates that mean percent (%) moisture content was found 76.72 ± 1.82, 77.31 ± 2.63, 78.92 ± 2.12, 77.89 ± 1.09, 78.11 ± 1.45 and 76.50 ± 1.56 for T-O, T-I, T-II, T-III, T-IV and T-V, respectively. Lowest mean value of percent moisture content was found in T-V, while highest value was noted in T-II. The highest mean protein content (%) in C. catla was found in T-V (Vitamin C) while lowest in T-II (CuO-NPs 4 mg/kg). Concentrations of cadmium, lead and cobalt were non-quantifiable among all treatment groups, while the concentration (µgg -1 ) of all other studied metals (Fe, K, Na, Zn, Cr and Cu) found below the permissible limits. Regression analysis used to examine how different treatments affected the amounts of different elements in different studied groups. The levels of Fe, K, Na, and Zn were found higher in CuO-NPs treatments (T-I, T-II) compare with Vitamin C (T-III, T-IV), while the levels were levels found higher in T-V and highest in control group. Activities of digestive enzymes in various groups showed a significant difference with maximum value of protease activity in T-V (5.734 ± 0.60 U/mL.min -1 ), while lower in T-II (4.68 ± 0.78). Activities of amylase was found maximum value in T-V (0.74 ± 0.14 U/mL.min -1 ), while lower in T-V (0.54 ± 0.19). Maximum activities of lipase activity were observed in T-0, while lower in T-II.