Zilberg D.,Ben - Gurion University of the Negev |
Tal A.,Ben - Gurion University of the Negev |
Froyman N.,Central Fish Health Laboratory |
Abutbul S.,Ben - Gurion University of the Negev |
And 2 more authors.
Journal of Fish Diseases | Year: 2010
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 MIC24 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 MIC24 h. Repeated exposures of S. iniae to rosemary did not affect minimal inhibitory concentration, suggesting no development of resistance to rosemary. © 2010 Blackwell Publishing Ltd.
Klas S.,Technion - Israel Institute of Technology |
Perlberg-Banet A.,Dor Research Facility |
Smirnov M.,Central Fish Health Laboratory |
Zivan A.,Technion - Israel Institute of Technology |
And 3 more authors.
Aquacultural Engineering | Year: 2014
Grey mullet fingerlings were grown in different acclimation solutions for three consecutive years, with the aim of developing a procedure for their adjustment to commercial growth in very low salinity (EC=0.37dS/m) and Cl-/Na+-deficient inland water (Dan River water, Northern Israel). Tested acclimation conditions composed of simulative solutions of varying ionic compositions (EC range 1.0-1.1dS/m) and a solution made up by dissolving quarry dolomite beads into the target (Dan River) water by H2SO4 without and with a small NaCl addition (1.5mM). The latter alternative was favored because of its low production costs and minimal environmental impact (minute addition of extrinsic Na+ and Cl- ions to the environment). The results obtained in the three experimental sets showed that stocking the fingerlings in a ~1dS/m acclimation solution for 1 week, followed by 20% daily dilution by the target water, was appropriate for attaining survival rates higher than 70% in all acclimation solutions tested (growth periods varied in the range 43-77d). Survival rate in brackish water control experiments was 85-95%. In the absence of an acclimation period the fish survival rate was ~35%. No significant difference was observed in fish growth rates between treatments conducted in a given year, suggesting that fish that survived the acclimation period would grow in the low salinity water at a rate similar to fish grown in brackish water. The minor differences in survival and growth results between the different acclimation solutions seemed to indicate that the role of specific ionic constituents in the water was inconsequential and that the most significant parameter is the overall water salinity. However, histological analyses revealed that applying the acclimation period with very low Cl- and Na+ concentrations (<~75mg/L and ~45mg/L, respectively) caused non-reversible adverse effects on the fish, whereas in all of the other treatments recorded adverse effects were of a reversible nature. Considering all the results, the best acclimation solution was defined as dissolution of dolomite by H2SO4 into the target low-salinity water plus addition of 1.5mM of NaCl. The cost of producing the acclimation solution was shown to amount to only ~0.03% of the overall culture cost. © 2014 Elsevier B.V.
Caffara M.,University of Bologna |
Davidovich N.,Central Fish Health Laboratory |
Falk R.,Central Fish Health Laboratory |
Smirnov M.,Central Fish Health Laboratory |
And 4 more authors.
Parasite | Year: 2014
Clinostomidae are digeneans characterized by a complex taxonomic history, continuously under revision based on both morphological and molecular analysis. Among the 14 species considered valid so far Clinostomum phalacrocoracis has been well described only at the adult stage, whereas the morphology of the metacercarial stage has been reported only once. During a parasitological survey carried out on 262 wild cichlids sampled from Lake Kinneret (Israel) metacercariae referable to C. phalacrocoracis were found in 18 fingerlings. In this study, we report this clinostomid species for the first time in wild fish from Israel describing the metacercarial stage of Clinostomum phalacrocoracis, coupling its morphological description with molecular analysis carried out on ITS rDNA and COI mtDNA sequences. © M. Caffara et al., published by EDP Sciences, 2014.