Hematological and biochemical parameters in common carp, Cyprinus carpio, following herbal treatment for Aeromonas hydrophila infection

The common carp, Cyprinus carpio was injected 108 cfu/ml with a strain of the Gram-negative bacterium, Aeromonas hydrophila. After inoculation, the disease signs began on the 7th day as a haemorrhagic spot at the site of injection and the lesion subsequently progressed in size. After this period, the mortality of infected group was 10±5% daily; hence, they were dip treated with an aqueous Azadirachta indica leaf extract at 1 g/l for 10 min daily for 30 days until the lesions healed completely. The hematological and biochemical parameters of the infected and control fishes were monitored on the 10th, 20th and 30th day. The white blood cell (WBCs: 104 mm−3) counts significantly increased from 3.15±0.14 in control fish to 3.6±0.20 on the 10th day of treatment (P<0.01) and only in treated fish (P>0.05) on the 30th day. The red blood cell (RBC: 106 mm−3) counts also significantly decreased to 1.68±0.12 on the 10th day (P<0.001) when compared to the control fish (2.31±0.16). The hemoglobin (Hb) and hematocrit/packed cell volume (PCV) counts decreased significantly from 10.37±0.61 and 33.60±3.20 in the infected fish to 6.21±0.60 and 20.30±3.8 in the treated fish on the 10th day and this value attained a normal level on the 30th day. On the 10th day of treatment, the serum protein level significantly (P<0.01) increased from 3.34±1.32 in controls compared to 3.61±0.96 in treated fishes. It subsequently remained high but attained near normal (P>0.05) values on the 30th day. In infected fishes the values continued to decrease significantly from 2.76±0.69 on the 10th day to 2.38±0.39 on the 30th day. Serum glucose, cholesterol and serum calcium levels were significantly lower in control fishes (119±16.93, 10.00±1.39 and 4.88±0.34) compared to treated fishes (77.63±15.57, 6.11±1.55 and 3.62±0.39) on the 10th day of treatment. In the infected fishes, the values continued to decrease significantly from the 10th day (64.6±11.97, 4.37±1.39 and 3.30±0.46) and by the 30th day reached 56.10±9.56, 4.31±0.91 and 2.88±0.52, respectively.