Effects of Feed Quality on Growth and Feed Utilization of Gilthead Seabream (Sparus aurata, L.) at Low Temperatures

The gilthead seabream (Sparus aurata) is cultured throughout the Mediterranean; the sea temperature most significantly determines the duration of farming. Sea temperatures reduce gilthead seabream’s need for feed and fish growth is not expected in these conditions. It is hypothesized that improving feed formulation could improve growth during the winter months. For the research, two groups were formed, and fed for a month with two types of fish feed of different nutritional composition at an average temperature of 13.9 ± 0.90 °C. The fish from cage A (21.53 ± 1.53 cm; 173.77 ± 38.24 g) were fed fish feed containing protein and lipid 100% from marine origin (H1). The fish from cage B (22.17 ± 1.43 cm; 181.08 ± 43.05 g) were fed with commercial feed for gilthead seabream, whose proteins and lipids were partially replaced by plant raw materials (H2). The temperature was measured daily and samples were taken at the beginning and end of the experiment for biometrics, which included the fish’s total length, total weight, and condition factor. This study showed that fish fed with a modified formula achieved higher growth parameters than fish fed with commercial feed. The data obtained indicate that gilthead seabream can grow at low temperatures and there is a need for further research to ensure the correct selection of raw materials for the testing and production of feed for the period of low sea temperatures.