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.

Striped catfish, Pangasianodon hypophthalmus, has recently emerged as a promising candidate for Egyptian aquaculture owing to its rapid growth; however, under intensive culture, it is vulnerable to Aeromonas hydrophila. The efficacy of dietary supplementation with effective probiotic microorganisms (EPMs) in enhancing growth performance, feed utilization, physiological health, and disease resistance of P. hypophthalmus against A. hydrophila challenge was evaluated. A 90-day feeding trial was conducted with 300 fish randomly distributed into four triplicate groups (25 fish per replicate) reared in 12 indoor fiberglass tanks: a control and three groups receiving EPMs at inclusion levels of 1.5%, 3%, and 4.5%. The results showed significant, dose-dependent improvements across all EPMs-supplemented groups in survival, growth rates, feed utilization, and hematological parameters (RBC, Hb, PCV, WBC, and lymphocytes). Dietary EPMs led to significant improvements (p ≤ 0.001) in digestive efficiency, protein and lipid metabolism, antioxidant enzyme activity, immune performance, and the ability of striped catfish to withstand A. hydrophila infection. Hepatobiliary enzyme activities (ALT, AST, and ALKP), glucose levels, lipid profile markers, and hepatic MDA exhibited a significant linear decrease (p ≤ 0.0001) with increasing EPMs levels. The gut microbial composition showed a dose-dependent increase in beneficial lactic acid bacteria (LAB) and a reduction in TAPC, pathogenic coliforms (TFCC), and Vibrio spp. (TVC). These results demonstrate the dose-dependent effects of EPMs on enhancing aquafeed efficiency, overall health, and innate immunity in striped catfish.

Optimizing sustainable aquaculture in the face of rising global demand requires the adoption of ecologically sound and resource-efficient production systems. In this context, the present study assessed the performance of European seabass (Dicentrarchus labrax) cultured in integrated multi-trophic aquaculture (IMTA) systems based on saline groundwater (SGW), incorporating grey mullet (Mugil cephalus) and clams (Ruditapes decussatus) as complementary species. During a 90-day period, four culture treatments were compared: monoculture (T1), seabass–mullet co-culture (T2), seabass–clam co-culture (T3), and a fully integrated IMTA system (T4). The IMTA configuration (T4) demonstrated significantly better outcomes (p < 0.05) in growth performance (final weight: 106.0 ± 0.2 g; specific growth rate: 2.62 ± 0.03%/day), survival (91.1 ± 2.2%), and feed utilization (feed conversion ratio: 1.60 ± 0.14; protein efficiency ratio: 1.41 ± 0.14) compared with the other systems. Nutritional analysis of the fish whole body revealed improved body composition in the fully integrated IMTA group, with increased crude protein (56.6 ± 0.2%) and energy content (555.4 ± 0.1 kcal/100 g), thereby aligning with market preferences for functional and health-promoting seafood. Overall, the study underscores the potential of SGW-based IMTA systems to enhance aquaculture productivity and sustainability, offering a scalable model well-suited for application in arid and water-limited environments.