Effect of different levels of dietary magnesium nanoparticles on growth, digestive enzymes activity and immune factors of common carp (Cyprinus carpio) under glyphosate exposure

The aim of this study was to evaluate the effects of different doses of magnesium-oxide nanoparticles (nano-Mg) on the growth performance, digestive enzyme activities, and some innate immune parameters in common carp fingerling (Cyprinus carpio). Nano-Mg was added to the experimental basal diets at the rates of 0 (control), 25, 50 and 100 mg/kg. Four groups of fish with an average weight of 12.96± 0.41 g were fed one of the experimental diets for 60 days. Fish that were fed diet supplemented with 25 mg nano-Mg/kg displayed improved growth performance, including final weight and weight gain, average daily gain and Specific Growth Rate (p<0.05). Feed conversion ratio was significantly lowered in fish fed with 25 mg of nano-Mg compared to control (p<0.05). Intestinal digestive enzyme activities (Amylase, Lipase and Protease) were significantly affected by dietary magnesium-oxide nanoparticles. At the end of the experiment, fish were exposed to chronic glyphosate herbicide for 14 days. Before and after stress, the highest lysozyme activity and lowest cortisol hormone level were obtained in 25 mg nano-Mg/kg diet. Liver enzymes (before and after stress) were significantly increased in the control compared to the other experimental treatments (p<0.05). According to the result of the present study, addition of 25 mg nano-magnesium per kg feed improves growth, digestive enzyme secretion and innate immunity of common carp and counteracts the adverse effects of glyphosate toxin.