The effect of chitosan nanoparticles coated with folic acid to feed on growth parameters in rainbow trout (Oncorhynchus mykiss) fingerlings

 The aim of this study was to investigate the effect of chitosan nanoparticles containing folic acid in the diet of rainbow trout, Oncorhynchus mykiss on growth and survival indices. For this purpose, rainbow trout with an average weight of 30 ± 2 g were divided into five experimental treatments: 0, 0.1, 0.25, 0.5 and 1 mg of chitosan/folic acid nanoparticles per kg of diet. Each treatment containing 25 fish in 3 repetitions in 15 tanks (500 liter) was designed into a closed-circuit breeding system. After making a manual diet and adapting the fish to the new conditions they were fed for 8 weeks. At the end of the experiment period, growth and survival indices were evaluated. The highest growth rate was recorded in the treatment of 1 mg/kg of chitosan/folic acid nanoparticles at the rate of 69.23 ± 4.34 g. With increasing Ch/FA nanoparticles levels in the formulated diets, the feed conversion ratio decreased linearly, which in fish fed with 1 mg/kg diet supplemented with chitosan / folic acid nanoparticles reached to 1.29 ± 0.08 (p < 0.05). On the other hand, the survival rate was the same in all treatments, but at the end of the period, losses were clearly observed in the control. The results showed that increasing the level of chitosan/folic acid nanoparticles in formulated diets will increase the growth rate and have a positive effect on growth index.