Effect of diets supplemented with feed additives on growth, feed utilization, survival, body composition and intestinal bacterial load of early weaning European seabass, Dicentrarchus labrax post-larvae

The present study was carried out to evaluate the effect of supplementation of Garlen®, Diamond V XPC®, and Bactozyme® and their combination in the diets of European sea bass, Dicentrarchus labrax larvae development in hatcheries on feed intake, growth performance, feed efficiency, intestinal bacterial, survival rate, and economics analysis. Dicentrarchus labrax juveniles (1.4 ± 0.5 mg) were distributed into eight experimental groups with a density of 2.5 larvae per liter. Eight iso-nitrogenous (55% crude protein) and iso-caloric (19.2 ± 0.2 MJ/kg, DM) weaning diets were formulated to contain the control diet (no feed additives), individually or mixed alternatively with three feed additives (Garlen®; Diamond V XPC®, and Bactozyme®). Each experimental diet was allocated to three tanks of fish and fed for 12 weeks. Growth and survival rate (S %) were improved for larvae fed the diets supplied with either (Diamond V XPC® + Bactozyme®) or (Garlen® + Diamond V XPC® + Bactozyme®), respectively compared to the control larvae group. The best FCR value was recorded for larvae fed a diet supply with (Garlen® + Diamond V XPC® + Bactozyme®), while the control larvae group recorded the worst FCR. The optimum significant (P ≤ 0.05) nutrient utilization values, larvae body crude protein content, activity test (ATV%), and profit index (PI) values were observed for larvae fed a diet containing Diamond V XPC® + Bactozyme® or Garlen® + Diamond V XPC + Bactozyme® compared to other treatments. The opposite trend was observed for total bacterial (TBC) and Vibrio sp. counts. No significant (P ≥ 0.01) difference was recorded in Aeromonas sp. count values in all experimental treatments. The results from this study show that (Garlen®; Diamond V XPC®, and Bactozyme®) individually or mixed alternately as growth promoters and immune stimulants in early weaning larval diets of European sea bass under hatchery conditions led to improve growth performance, feed utilization, survival, lowest intestinal bacterial load, and highest profit index (LE).