Akademik Veri Yönetim Sistemi
Animal Feed Science and Technology, cilt.341, 2026 (SCI-Expanded, Scopus)
This 70-day feeding trial evaluated the effects of dietary barberry (Berberis vulgaris) fruit extract (BFE) supplementation—at 0, 0.5, 1, and 2 g/kg diet—on growth performance, feed utilization, body composition, antioxidant defense, stress responses, hematology, and histology in rainbow trout (Oncorhynchus mykiss). Growth and feed utilization were significantly affected by dietary BFE levels (P < 0.05). Although the BV1 diet resulted in the highest final weight, % weight gain, specific growth rate, and feed efficiency, further BFE supplementation provided no additional improvements over the control. Whole-body proximate composition and fatty acid profiles were not significantly influenced by the experimental diets. Similarly, hematological parameters, activities of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx), and glutathione (GSH) level did not significantly differ among treatments. However, lipid peroxidation level was significantly lower (P < 0.05) in fish fed the BV2 diet compared to the other groups. Serum glucose concentrations remained unaffected while fish fed the BV2 diet had significantly lower cortisol level compared to the other groups (P < 0.05). Histopathological examination revealed degenerative changes in the liver and intestinal epithelium of fish receiving the BV2 diet, while the other groups exhibited normal histological structures. Overall, our findings showed that BFE supplementation at a dose of 1 g/kg improved growth performance and feed efficiency in rainbow trout. On the other hand, no improvement in growth was observed at a dietary dose of 2 g/kg, and furthermore, tissue degeneration was observed. Thus, our results indicate that the optimum BFE supplementation level is 1 g/kg diet. Future studies could define different intermediate dose ranges between 1 and 2 g/kg feed, allowing for more precise level estimation via broken line regression analysis, thus enabling more effective and safe use of BFE in rainbow trout feeding.