水産養殖研究開発ジャーナル

概要

Effect of Ginger (Zingiber officinale) on Hematological Parameters and Resistant to Aeromonas hydrophila Infection in Nile tilapia, Oreochromis niloticus L.

Alazar Ergena, P Natarajan, Zufan Bedewi

Aquaculture is one of the fast growing food industries in the world. However, this industry is hampered by diseases. The present study aimed to determine the effect of ginger powder on the haematology of Oreochromis niloticus, and resistance to Aeromonas hydrophila infection. A completely randomized design was used for the experiment. A total of 300 healthy live experimental fish 20 ± 1.00 g of body weight and 11.06 ± 0.08 cm body length were randomly divided into five treatment glass aquariums. Each in triplicates, representing four treatments (3 g, 5 g, 8 g and 12 g ginger/kg diet) and one control (0.00 g/kg diet). After eight weeks of feeding trial 0.2 ml of A. hydrophila culture containing 1.0 × 10⁷ CFU/ml (LD₅₀) was given by Intra-peritoneal (IP) injection. Blood samples were collected before and after the bacterial infection of the fish for haematological analysis. The result showed that blood parameters of Oreochromis niloticus in all ginger concentrations were significantly higher compared to the control diet before infection (P<0.05). Oreochromis niloticus fed a diet at a concentration of 5 g/kg feed had the highest Red Blood Cell (RBC), haematocrit, haemoglobin, Mean Corpuscular Haemoglobin (MCH), Mean Corpuscular Haemoglobin Concentration (MCHC), White Blood Cell (WBC), lymphocytes and monocytes. Erythrocyte Sedimentation Rate (ESR), Mean Corpuscular Volume (MCV), WBC, neutrophils and monocytes show significant increment, while RBC, haemoglobin, haematocrits, MCH, MCHC and lymphocytes decrease significantly after infection (P<0.05). The results also revealed that the fish treated with 5, 8 and 12 g/kg ginger showed a decrease in mortality rates compared to the control diet after infection. The fish fed 5 g/kg ginger had the highest survival rate (81.66%). In conclusion, 5 g/kg of ginger had positive effects on O. niloticus innate immunity system and prevents A. hydrophila infection. Hence, the use of 5g/kg dietary ginger powder in juvenile O. niloticus die is recommended.