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    Effect of Total Isoflavones Found in Soybean on Vitellogenin Production in Common Carp
    (Kafkas Univ, Veteriner Fakultesi Dergisi, 2009) Turker, Hakan; Bozcaarmutlu, Azra
    Soybean meal is used most extensively as a replacement to fishmeal as the main protein source in fish diets. However. there is concern about the effect of soybean-based diets on reproductive development of the fish because of the phytoestrogenic properties of soybean. The objective of the present study was to determine whether a relationship exists between the concentration of soybean extract containing total isoflavones in diet and the production of vitellogenin protein in cyprinid fish. Five different doses (0, 250, 500, 1,000, and 10,000 mg/kg based on total isoflavones content) of commercial soybean extract were tested to determine the effect of pyhtoestrogens concentration on vitellogenin synthesis in female and male carp. Cyprinius carpio L. There were no significant differences in the growth of fish between any of the groups All concentrations of soybean extract lowered male gonadosomatic index (GSI). but female GSI was increased in diets including up to 500 mg/kg soybean extract, and then decreased at higher doses. This was associated by an inhibition and induction, respectively. in plasma vitellogenin levels. Changes in GSI and vitellogenin appeared to be sensitive marker for detecting phytoestrogens exposure. Higher concentrations of isoflavones resulted in a higher amount of vitellogenin produced in both male and female fish. Our results clearly showed that exposure to phytoestrogens found in soybean extract significantly induces vitellogenin production in both males and females, in a dose-response manner. GSI and high vitellogenin production indicated that phytoestrogens found in soybean disrupt the endocrine system of fish. The endocrine disruptor effect of soybean products must be considered in fish meal preparation.
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    Sensitivity of Bacteria Isolated from Fish to Some Medicinal Plants
    (Central Fisheries Research Inst, 2009) Turker, Hakan; Yildirim, Arzu Birinci; Karakas, Fatma Pehlivan
    Alcoholic and aqueous extracts from 22 species of herbs from Bolu (Turkey) were screened for antibacterial activity against Aeromonas hydrophila, Yersinia ruckeri, Lactococcus garvieae, Streptococcus agalactiae and Enterococcus faecalis. Extracts with various solvent of Nuphar lutea, Nymphaea alba, Stachys annua, Genista lydia, Vinca minor. Fragaria vesca, Filipendula ulmaria, Helichrysum plicatum showed the highest inhibitory activity. The ethanolic extract of V. minor and the alcoholic and aqueous extract of N. lutea displayed a broad antibacterial spectrum against the tat-get organisms. The possible usage of herbs as an alternative to synthetic antibiotics is discussed.