Evaluation of dietary administration of nettle (Urtica dioica) and dwarf elder (Sambucus ebulus) on growth, hematological, immunological indices and survival of common carp (Cyprinus carpio) against Aeromonas hydrophila

In this study, dry leaf powder of nettle and dwarf elder in two combinations and three treatments including treatment 1 (dwarf elder 50 g + nettle 60 g/ kg diet), treatment 2 (dwarf elder 50 g + nettle 120 g g/ kg diet) and control (normal diet) were used  and 180 carp (52.64 ± 2.74 g) were fed during 8 weeks. The blood samples were taken in the 4 and 8 week of the trial. At the end of week 8, the fish were challenged to Aeromonas hydrophila. The results showed that the final weight, body weight gain and specific growth rate in treatment 2 and the food conversion factor of this treatment significantly increased and decreased, respectively, compared to the control. The levels of MCV, MCH, MCHC, glucose, cholesterol, albumin, alanine aminotransferase and aspartate aminotransferase were not shown any significant difference between the treatments and the control. In the 4th and 8th week, the amount of red blood cells, hematocrit and hemoglobin of the treatments were significantly higher than the control. At the end of week 4, the amount of white blood cells was significantly different between treatment 2 and the control, but at the end of week 8, this index increased significantly in the treatments compared to the control. The percentage of neutrophil cells, total protein and total IgM in the treatments in weeks 4 and 8 were increased significantly compared to the control. The amount of triglycerides of the treatments in the 8th week had a significant decrease compared to the control. During the 4th and 8th week, the lysozyme activity of the treatments increased significantly compared to the control, and the highest activity was in treatment 2. In week 4, the oxygen free radical production of treatment 2 had a significant increase compared to the control, but in week 8, a significant increase were seen in the treatments compared to the control. The percentages of survival after challenging to Aeromonas hydrophila were 71.6%, 69.9% and 22.6% in the treatment 1, 2 and control, respectively. The results of this study showed that using the combination of nettle and dwarf elder in both treatments can improve the growth and safety of carp fish, but treatment 2 had better results.