Ayşegül Aydın

In this study, a 60‐day trial was conducted to determine the effects of curry plant (Helichrysum italicum) extract in the diet of rainbow trout (Oncorhynchus mykiss) with an initial average live weight of 15.84 ± 0.05 g on growth performance and gene expressions associated with digestion, antioxidant capacity, and immune response. Four experimental diets were formulated as a basal diet (Control; C) and diets supplemented with varying levels of curry plant extract (CP05; 0.5 g kg⁻¹, CP1; 1 g kg⁻¹, and CP2; 2 g kg⁻¹). Growth indices showed significant increases in all curry plant extract groups compared to the C group (p < 0.05). Similarly, higher levels of trypsin, lipase, and amylase expressions were observed in the curry plant extract groups compared to the C group (p < 0.05). The superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) gene expression levels were elevated in the CP extract groups (p < 0.05). The expression levels of interleukin‐1β (IL‐1β), tumor necrosis factor (TNF‐α), and interleukin‐8 (IL‐8) were also influenced by the incorporation of CP extract into the diet, showing significant changes (p < 0.05). In conclusion, this study experimentally demonstrates that supplementing the diet of rainbow trout with CP extract can positively influence healthy growth parameters.

Determination of the dietary composition and feeding habits of fish is important to explore and compare trophic interactions, food web structure, population, and ecological dynamics within and between aquatic ecosystems and to ensure sustainability. Factors such as global warming in the world and the effects of human activity cause the reduction of fish populations to the deterioration of the ecological balance. That is why we need to fill scientific knowledge gaps to discover and protect biodiversity. In this study, studies that determine the dietary composition of fish species distributed in our country's waters were brought together and the methods used were examined. When we examine these studies; It has been observed that information on the diet compositions of threatened and important commercial fish species is lacking, and existing studies are concentrated in certain areas. It has been determined that the studies carried out in the Black Sea and Aegean Seas are more than in the Mediterranean and Marmara Seas, there are no studies in the Southeastern Anatolia region, and there are few studies in the inland waters of the Mediterranean, Marmara, and Aegean regions.