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Dried leaves of Rosmarinus officinalis as a treatment for streptococcosis in tilapia
Author(s) -
Zilberg D,
Tal A,
Froyman N,
Abutbul S,
Dudai N,
GolanGoldhirsh A
Publication year - 2010
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/j.1365-2761.2009.01129.x
Subject(s) - rosmarinus , streptococcus iniae , biology , officinalis , tilapia , oreochromis , oxytetracycline , cultivar , zoology , horticulture , fish <actinopterygii> , botany , antibiotics , microbiology and biotechnology , fishery
Dietary application of dried Rosmarinus officinalis (rosemary) leaves as a treatment for streptococcal infection was studied in tilapia, Oreochromis sp. Feeding with dried rosemary leaves significantly reduced mortality following infection with Streptococcus iniae : 44% mortality in the group fed 8% rosemary, similar to oxytetracycline treatment (43% mortality), and significantly lower than the control (65%). Dietary administration of 16% rosemary significantly reduced mortality because of Streptococcus agalactiae infection in 44 g fish (62% and 76% in 16% rosemary and control, respectively), but not in a similar experiment conducted with 5.5 g fish. The antibacterial effect of rosemary on S. iniae was studied. Activity of rosemary cultivar Israel was reduced during the winter, but there was no significant change in cultivars Oranit and Star. Storage of powdered rosemary leaves at 50 °C resulted in fourfold and eightfold higher MIC 24 h values after 3 and 4.5 months, respectively. Storage at −20 °C, 4 °C and 25 °C and autoclaving (120 °C) each resulted in a twofold increase in MIC 24 h . Repeated exposures of S. iniae to rosemary did not affect minimal inhibitory concentration, suggesting no development of resistance to rosemary.