The Impact of Dietary Curcumin on the Growth Performance, Intestinal Antibacterial Capacity, and Haemato-Biochemical Parameters of Gilthead Seabream (Sparus aurata)

SIMPLE SUMMARY: In aquaculture, dietary curcumin has been shown to enhance the growth rate, antioxidative status, immunity, and disease resistance of several finfish species. Nevertheless, the potential role of curcumin has not been evaluated in Gilthead seabream as yet. Herein, we tested the effect of dietary curcumin on the growth performance, intestinal antibacterial capacity, and haemato-biochemical parameters of Gilthead seabream. Curcumin was mixed with the basal diet at rates of 0, 1.5, 2, 2.5, and 3%, then fed to the fish for 150 days. The results indicated marked improvements in the growth performance, feed efficiency, and antibacterial capacity of the fish. Further, curcumin enhanced the hematological indices and regulated the biochemical blood metabolites of Gilthead seabream. Dietary curcumin is recommended at a rate of 2–3% to improve the performance of Gilthead seabream. ABSTRACT: The need to replace antibiotics in aquafeed is increasing, and alternative safe substances are now encouraged for sustainable aquaculture activity. Curcumin is regarded as a multifunctional feed additive with growth-promoting and immunostimulant potential. Thus, this study evaluated dietary inclusion of curcumin at rates of 0, 1.5, 2, 2.5, and 3% in the diets of Gilthead seabream for 150 days. The results showed an improved final body weight, weight gain, specific growth rate, and feed conversion ratio in fish treated with curcumin, in a dose-dependent manner. The highest growth performance was observed in fish fed a diet supplemented with 3% curcumin. The results also showed lowered activity of pathogenic bacteria (Vibrio spp. and Faecal coliform) in the intestines of Gilthead seabream fed a diet with curcumin inclusion, in a dose-dependent manner. The hematological indices were within the normal range for healthy fish, without meaningful effects except for hematocrit, hemoglobin, red blood cells (RBCs), and white blood cells (WBCs), which were markedly increased by dietary curcumin. Phagocytic activity was obviously enhanced by dietary curcumin, compared with the control. The biochemical blood metabolites related to liver function (alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT)), renal tissue (urea), and total cholesterol were within the normal values, without significant differences. Overall, the inclusion of curcumin at a rate of 2–3% improved the growth performance and well-being of Gilthead seabream.