Protective effect of D-limonene derived from orange peel essential oil against Yersinia ruckeri in rainbow trout

The nutritional study was performed for 90 days to assess the potential protective effect of three concentrations (0.5, 1, and 3 mL/kg) of D-limonene derived from orange peel essential oil against Yersinia ruckeri in rainbow trout. Mean corpuscular volume, mean corpuscular hemoglobin, serum glucose, alanine aminotransferase, total protein, and globulin were unaffected by any D-limonene treatment group. Red blood cell count, hematocrit level, hemoglobin concentration, mean corpuscular hemoglobin concentrations, cholesterol, triglyceride, alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase, and albumin were significantly changed among groups. No histological differences were observed in liver tissue cross-sections between the control and treated groups. Lysozyme activity, myeloperoxidase, superoxide dismutase, and phagocytic activity were significantly changed among groups. At the challenge test with Y. ruckeri, fed with D-limonene groups showed a high survival rate. According to results, diets with D-limonene may have an application for rainbow trout production. Consequently, the use of natural products is important on antibiotic resistance in teleosts and humans, compared to the alternative use of chemical therapeutics to manage fish diseases and lower incidence in aquaculture.