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Öğe Accumulation of some heavy metals in Hysterothylacium aduncum (Nematoda) and its host sea bream, Sparus aurata (Sparidae) from North-Eastern Mediterranean Sea (Iskenderun Bay)(Springer, 2011) Dural, Meltem; Genc, Ercument; Sangun, M. Kemal; Guner, OzlemThe sea bream's nematode and Sparus aurata, sampled from the Iskenderun Bay, Mediterranean, in March 2008 were analyzed by inductively coupled plasma-atomic emission spectrometry for their some heavy metal (Cd, Cr, Cu, Fe, Hg, Mn, Mg, Pb, and Zn) levels. The metal concentrations of the parasites were compared to different organs (liver, muscle, gill, intestine, and skin) of the fish hosts. There were significant differences in Cd, Cr, Cu, Fe, Mn, Zn, Hg, Mg, and Pb concentrations in tissues of fish and its parasite. The parasite Cd, Cu, and Pb concentration was higher than the other tissues. Furthermore, significant differences were detected in the heavy metal accumulations between the parasitized and unparasitized fish tissues in Cd, Cu, Hg, and Pb concentrations. The Cd, Hg, and Pb concentrations were found in fish muscle at mean concentrations over the permissible limits proposed by the Food and Agriculture Organization.Öğe Effects of Feeding Interval on Growth, Survival and Body Composition of Narrow-Clawed Crayfish, Astacus leptodactylus Eschscholtz, 1823 Juveniles(Central Fisheries Research Inst, 2011) Mazlum, Yavuz; Guner, Ozlem; Sirin, SinemNewly hatched third instars of Astacus leptodactylus (mean weight 44.5 +/- 3.4 mg and mean total length 10.8 +/- 0.4 mm) were randomly stocked in 0.2 m(2) aquariums at rate of 100 crayfish/m(2) fed with trout feed at a quantity 5% of crayfish body weight for 90 day. The amount of diet was adjusted according to the total crayfish biomass calculated for each sampling period (30-days interval). Four feeding intervals were tested: everyday (D), every 2(nd) (D2), every 3(rd) (D3), and every 4(th) day (D4). At the end of feeding period, the feeding interval had significant impact on crayfish survival, growth rate, and yield. The survival of crayfish was the highest in D2 treatment (83.3%) and was lowest in D4 treatment (57.2%). Results indicated that feeding interval in D2 treatment significantly increased survival of crayfish. Growth rates were significantly different (P<0.05) between D2 treatment (0.8 mm/day) and D4 treatment (0.5 mm/day) at the end of the 90-day experiment. The best growth rate was observed in D2 treatment group. The yield was found to decrease with increasing length of feeding interval. The highest yield (27.65 g) was observed in D2 treatment, while the lowest yield (12.6 g) was in D4 treatment. The feeding interval had no significant difference on body composition of A. leptodactylus juvenile among the treatment groups (P>0.05). The study showed that the optimal feeding interval was observed every 2(nd) day.Öğe A preliminary study on the use of mannan oligosaccharides (MOS) in freshwater crayfish, Astacus leptodactylus Eschscholtz, 1823 juvenile diets(Springer, 2011) Mazlum, Yavuz; Yilmaz, Erdal; Genc, M. A.; Guner, OzlemThe effects of dietary mannan oligosaccharides (MOS) on the survival and growth of Astacus leptodactylus juveniles were evaluated. Experimental diets were prepared by using supplementation of 0 (Control), 1.5, 3.0, and 4.5 g MOS kg(-1) commercial trout larvae diet containing 43 g kg(-1) protein and 15.74 g kg(-1) lipid. A. leptodactylus juvenile with an average total length of 3.6 +/- 0.46 cm (TL) and average weight of 1.25 +/- 0.43 g was stocked in 0.2-m(2) aquariums at a rate of 50 crayfish/m(2) and reared for 60 days at 22.8 degrees C. The experiment consisted of four treatments with three replicates each. Each aquarium contained ten crayfish. Crayfish juvenile fed with 0, 1.5, 3.0, and 4.5 MOS attained 6.15 +/- 0.49, 5.94 +/- 0.29, 7.34 +/- 0.39, and 5.94 +/- 0.27 cm final total length and 50, 56.67, 46.67, and 50% survival rates, respectively. Moreover, molting frequencies in 0, 1.5, 3.0, and 4.5 g kg(-1) MOS groups were detected as 44.44, 61.11, 83.33, and 38.88%, respectively. At the end of the experiment, a general enhanced growth performance (P < 0.05) and feed conversion ratio were observed in crayfish fed on the diet containing 3.0 g kg(-1). Crayfish juveniles fed with 3.0 g kg(-1) MOS had the highest final length (7.34 +/- 0.39 cm), although their survival was the lowest (46.67%) compared to other treatments but not significant. Specific growth rates were significantly different (P < 0.05) among the treatment groups at the end of the 60-day experiment. There were no significant differences (P > 0.05) in percentage moisture, protein, and ash (wet-weight basis) in the tail meat of A. leptodactylus juvenile among treatments (diet) that averaged 82.3, 16.1, and 1.2%, respectively. However, lipid value was significantly different among the diets P < 0.05), with values between 0.13 and 0.32. From the current results, it could be advised to use MOS at the rate of 3.0 g kg(-1) in A. leptodactylus juvenile diets.