Dietary effects of lemon Citrus limon peel essential oil encapsulated in chitosan nanoparticles on hematological indices and antioxidant defense system of rainbow trout Oncorhynchus mykiss

This study was conducted to evaluate the effect of dietary levels of lemon essential oil encapsulated in chitosan nanoparticles on hematological indices and antioxidant status of rainbow trout fry. Accordingly, the fish (4.74 ± 0.14 g in weight) were distributed in 12 fiberglass tanks with 20 fish per tank and were fed with different levels of lemon essential oil loaded in chitosan nanoparticles including control group with no additive (C0%), 0.5% (T0.5%), 0.75% (T0.75%) and 1% (T1%) for 8 weeks in triplicates. The results showed that the highest number of RBC was in T0.75% compared to T0.5% and C0% (p<0.05). The maximum hemoglobin value was observed in T1% and T0.75% compared to the other experimental groups (p<0.05). In addition, in terms of the blood indices, MCH index showed a significant increase in T1% and T0.75% compared to the other treatments. The maximum WBC and lymphocytes were observed in T1% compared to the other experimental groups (p<0.05). Serum antioxidant enzymes showed the highest catalase activity and glutathione peroxidase in T1% compared to the other groups (p<0.05). Furthermore, superoxide dismutase activity elevated significantly only in T1% compared to C0% (p<0.05). However, the oral administration of 0.75% and 1% of lemon peel essential encapsulated with nanochitosan resulted in a significant elevation in the serum malondialdehyde compared to T0.5% and C0% (p<0.05). Overall, the results of this study showed that the addition of lemon essential oil encapsulated in chitosan nanoparticles, especially at 1%, can enhance the hematological indices and antioxidant defense system of rainbow trout.