Effect of Diets Supplemented with Functional Feed Additives on Growth, Feed Utilization, Carcass Traits, Haematological Status and Intestine Histology of Gilthead Sea Bream, Sparus aurata Fry Raised in Habas

Feed additives may improve fish immunology and water quality by controlling microbial communities and habitats. The present trial examined the impacts of four commercial functional feed products (probiotic, prebiotic, symbiotic, and organic acid) on the growth of gilthead sea bream, Sparus aurata fry. Five experimental diets were designed, four of which used commercial functional feed additives (Bactocell®, Agrimos®, Bactozume®, and Aquagest®) and one without supplementation as the control. The formulated diets contain 45% protein. The study included 15 hapas (2m × 1m × 1m representing five experimental groups, each in triplicate. A total of nine hundred fry, with a stocking density of 60 per hapa. Fish fry measuring 2.3 ± 0.01 g were fed at a progressive rate of 12% to 6% of total fish weight 3 times/d ^− 1 , seven days a week, for 75 days. NH ₃ levels were considerably lower in supplemented diet groups, mainly organic acid, versus basal diet. Fish fed Aquagest® (OA) showed considerably higher growth and feed utilization than other treatments. The study revealed no differences in proximal body composition between experimental treatments. The supplemented diet with different feed additives showed significant improvements in blood biochemistry indices versus basal diet. Histological intestine and liver data showed that a diet supplemented with various feed additives was healthier than the control. The present study highlight the role of inclusion of feed additives to enhance gilthead sea bream, Sparus aurata fry performance, blood biochemistry, immunity, and water quality.