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Öğe Effects of dietary lipid levels on growth performance and feed utilization in juvenile Black Sea turbot (Psetta maxima) with reference to nitrogen excretion(Adem Yavuz SÖNMEZ, 2014) Harmantepe, Fatma Burcu; Yigit, Murat; Dogan, Gaye; Karsli, Zafer; Yigit, Umut; Uyan, OrhanIn the present study, iso-nitrogenous test diets were formulated to contain two different levels of lipid (9% and 12%) with dietary energy ranging from 19 kJ/g to 20 kJ/g diet. White fish meal was the main protein source of the diet and the protein level was 55% in all diets offered to triplicate groups of juvenile Black Sea turbot (mean initial weight of 24.5±0.3 g) for a period of 70 days. Specific growth rates were significantly better (P < 0.05) in high lipid diet group compared to the groups fed low lipid diets. Feed conversion rates (FCR) were influenced by the lipid levels and the best FCR was obtained in fish given the diet with high lipid content. Similarly, protein efficiency was also significantly better (P < 0.05) in fish fed diets with high lipid level. The better utilization of protein in the diet with high lipid content resulted in a significantly higher (P < 0.05) nitrogen retention as percent of intake when compared to the other group with lower lipid level. The amount of nitrogen loss into the water environment was significantly reduced (P < 0.05) to the same extent in the group fed diets with high lipid level. The lipid retention values calculated based on the intake rates were also better in the high lipid diets compared to the other group with low lipid level, however the difference was not significant (P > 0.05) among the experimental groups. The results in the present study indicate that the use of high lipid level with a protein to energy ratio of 27 mg/kJ (12% lipid, 55% protein, 20 kJ/g gross energy) performed best. Increasing the dietary lipid to 20 kJ/g diet has reduced the total nitrogen excretion from Black Sea turbot by 23%.Öğe Effects of supplementing the rainbow trout (Oncorhynchus mykiss) diet with Spirulina and Chlorella on the tissue's cadmium detoxification capacity, growth performance, fatty acid composition, antioxidant defense system and liver histology(Elsevier, 2025) Harmantepe, Fatma Burcu; Gundogdu, Ayse; Karsli, Zafer; Sagir, DilekThis study aimed to determine the effects of the addition of Spirulina and Chlorella of the diets of rainbow trout (Oncorhynchus mykiss) on their growth, nutrient composition, the parameters of their antioxidant defense systems, liver histology, and the cadmium removal process of their tissues. Fish with an average weight of 84.25 +/- 3.55 g containing Cd in their tissues were distributed in 15 tanks with 18 fish per tank. The fish were fed diets consisting of 0% (Control-1), 0% (Control-2), 4% Chlorella, 4% Spirulina and Chlorella +2% Spirulina twice a day until they were satiated for a period of 80 days. At the conclusion of the experiment, it was determined that diets containing microalgae demonstrated increased growth rates, and that the growth values obtained from the 4% Spirulina and the Control-1 were similar (p > 0.05). Regarding the fatty acid content, with the addition of microalgae to the diet, a significant (p < 0.05) decrease in SFA values and a significant (p < 0.05) increase in PUFA values were observed compared to the groups Control-1 and Control-2. On days 40 and 80, Cd levels in the muscle and liver tissue of the fish were found to be significantly (p < 0.05) lower in the groups that were fed diets containing microalgae in comparison with the Control-2 group. On days 40 and 80, the SOD, CAT, GSH, GST, and GPx values of liver tissues were higher (p < 0.05) than those of the Control-2 group. As a result of the semiquantitative histopathological evaluation of the liver tissues, improvements were observed in all groups containing microalgae; however, the most remarkable improvement was achieved in the Spirulina group. The results obtained in the study revealed that the addition of microalgae to rainbow trout feed removed Cd from liver and muscle tissues, reinforced the antioxidant defense system parameters, and increased growth. However, when the groups containing microalgae were compared among themselves, the diets containing 4 % Spirulina and 2 % Chlorella +2 % Spirulina were found to be more effective on these parameters.