Growth Performance, Survival, Hematological Parameters, and Water Quality of European Seabass (Dicentrarchus labrax) Fed on Two Different Types of Probiotics as a Feed Supplement

This study aimed to investigate the effects of using two probiotic formulations on the European seabass (Dicentrarchus Labrax). Three diets (C= control diet without any probiotics, P₁= probiotics, and P₂= probiotics + enzymatic additives) and three fish densities (20, 40, and 80 F/m3) were used in 3 replicates. Healthy European seabass juveniles (IBW =5g) were obtained from a commercial farm in Damietta, Egypt. Fish were acclimated for 1 week before experiment. Diets with 45% crude protein were tested for 12 weeks. Water quality parameters were measured bi-weekly. Five fish per hapa were randomly taken to collect the blood sample for hematological assessment. Final body weight was significantly higher (P<0.05) in group P₂, with no significant variance based on densities. Groups P₁ and P₂ exhibited the highest significant specific growth rate (SGR) (P<0.05), with no significant differences based on densities. Furthermore, both P₁ with 20 fish/m³ and P₂ groups demonstrated significantly higher survival rates (P<0.05). Group P₂ achieved best FCR followed by P₁ and control. Density was recorded with a further significant effect on PER and ER, at densities of 80 fish/m3. Group P₂ (80 fish/m3) was displayed with the highest significant percentage of HCT compared to other groups. Levels of MCH and MCV were significantly high in P₁ with 40 fish/m3. The highest significant RBCs were recorded in P₁ with 80 fish/m³. The lowest significant WBCs was recorded in the control group with 40 fish/m³. The total protein was improved by the inclusion of two types of probiotics at different densities. The highest glucose level was recorded in the control with 80 fish/m³. The control group experienced a significant increase in cholesterol levels compared to the other groups. No significant differences were observed between the types of probiotics and the level of density in the triglyceride values. pH, DO and TAN were significantly improved for the groups of P₁ and P₂ compared to the control group. Notably, probiotics’ induction improves the host’s health and water quality.