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.

Dietary cinnamon has several bioactive compounds with growth-promoting and immunomodulation potential and is suggested for finfish species. This study evaluated the inclusion of cinnamon at 0, 10, 15, and 20 g/kg in European sea bass (Dicentrarchus labrax) diets. After 90 days, the highest final weight, weight gain, specific growth rate, protein efficiency ratio, and the lowest feed conversion ratio were seen in fish treated with 10 g/kg (p < 0.05). Further, the measured growth hormone in the blood indicated that fish treated with 10 g/kg had a higher level than fish 0 and 20 g/kg. After the feeding trial, fish treated with cinnamon at varying levels had higher lipid content than fish before the feeding trial (p < 0.05). Lower Vibrio spp. and Faecal Coliform counts were observed in fish treated with cinnamon than fish fed a cinnamon-free diet (p < 0.05). The hematocrit level was markedly (p < 0.05) increased in fish fed cinnamon at 10 g/kg compared to the control without significant differences with fish fed 15 and 20 g/kg. Hemoglobin was significantly increased in fish treated with cinnamon at 10, 15, and 20 g/kg compared to fish fed a cinnamon-free diet (p < 0.05). Red and white blood cells (RBCs and WBCs) were meaningfully (p < 0.05) increased in fish treated with cinnamon compared with the control. Markedly, fish treated with cinnamon had higher serum total lipids than the control with the highest value in fish treated with 15 g/kg (p < 0.05). The lysozyme activity was markedly higher in fish treated with 15 g cinnamon/kg than fish fed 0, 10, and 20 g/kg (p < 0.05). Moreover, phagocytic activity was significantly higher in fish treated with cinnamon at 10, and 15 g/kg than fish fed 0 and 20 g/kg (p < 0.05). In conclusion, dietary cinnamon is suggested at 10–15 g/kg for achieving the high production and wellbeing of European sea bass.

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Coriander seeds are among the functional herbal supplements, but their effects on aquatic animals are still lacking. Herein we evaluated the effects of coriander seeds on the growth performance, growth hormone, antibacterial capacity, and immune response of European sea bass (Dicentrarchus labrax). Fish with initial mean weights of 5.08 ± 0.12 g/fish were allocated in four groups (in triplicate) and fed dietary coriander at 0, 5, 10, and 20 g/kg for 150 days. The growth performance, feed utilization, and survival rate of fish-fed dietary coriander meaningfully increased (P<0.05). The protein efficiency ratio gradually increased (P<0.05) in fish-fed coriander seeds compared with the control. On the other hand, the feed conversion ratio was gradually decreased (P<0.05) in fish-fed coriander seeds comparing with the control. The survival rate was markedly increased (P<0.05) in European sea bass-fed dietary coriander regardless of the inclusion level. Further, no differences were seen among fish fed varying levels of coriander (P<0.05). The level of blood growth hormone was markedly higher (P<0.05) in European sea bass-fed dietary coriander at 20 g/kg than fish-fed 0 and 5 g/kg. The abundance of intestinal Vibrio spp. and Faecal Coliform were obviously lower (P<0.05) in fish fed 10 and 20 g/kg than fish fed the coriander-free diet. Further, fish fed 20 g/kg had lower (P<0.05) Vibrio spp. and Faecal Coliform counts than fish fed 10 g/kg. Fish fed dietary coriander had significantly higher (P<0.05) hematocrit, hemoglobulin, red blood cells (RBCs), and white blood cells (WBCs) than fish fed the control. The lysozyme and phagocytic activities were meaningfully increased (P<0.05) in fish fed 10 and 20 g/kg compared with fish fed 0 and 5 g/kg of dietary coriander. In conclusion, dietary coriander could be included in the diets at 10–20 g/kg to improve the growth performance, growth hormone, feed utilization, and immune response of European sea bass.

No abstract