Soltani M.,University of Tehran |
Mohamadian S.,University of Tehran |
Rouholahi S.,University of Tehran |
Soltani E.,University of Tehran |
Rezvani S.,Iran Institute of Fisheries
Aquaculture | Year: 2015
Lactococcosis caused by Lactococcus garvieae is known as one of the serious economical bacterial diseases in aquaculture species of both freshwater and marine fish at a wide range of water temperature mainly from 13. °C to 37. °C. The PavA gene and Hly gene, the genes responsible for encoding fibronectin and hemolysin proteins, respectively are the well known virulent factors of L. garvieae. The effect of essential oil of Zataria multiflora was evaluated on expression of these genes in two virulent isolates of L. garvieae isolates recovered from diseased rainbow trout. Fresh cultures of the bacterial isolates were exposed to 1/2-1/16 (0.12-0.015. μl/ml) of the minimum inhibitory concentrations (MIC) of Z. multiflora essential oil and the expression of PavA and Hly genes was assessed by real time PCR works. The results showed that under MIC concentration (0.12. μl/ml) of the essential oil, the expression of both Hly and PavA genes was significantly suppressed in both bacterial isolates (P. <. 0.05). Therefore, it is feasible to use Z. multiflora in forms of oral and/or bath administration to reduce morbidity and mortality by Lactococcus garvieae in fish via the suppression of expression of these virulent genes. © 2015 Elsevier B.V.