Effects of Multispecies Probiotic Combination on Growth Performance, Biochemical Indices, and Non-specific Immune Responses in Common Carp (Cyprinus carpio)

 Probiotic bacteria as an alternative to antibiotics are necessary for aquaculture due to the prevalence of recurrent diseases.

 This study investigated the effect of a probiotic combination, including endogenous bacteria such as Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus acidophilus, and Lactobacillus rhamnosus, on the health status of common carp.

 The probiotic combination was added to carp basal diets in three treatments, 1 to 3, each containing 106 CFU g-1, 107 CFU g-1, and 108 CFU g-1 probiotic combination, respectively. A fourth group (group 4) was used as a control and received no probiotic treatment for six months. After 3 months, the fish’s growth performance, biochemical indices, and innate immune responses were evaluated.

 The growth indices, such as the daily growth rate, specific growth rate, condition conversion factor, condition factor, and protein efficiency, significantly improved in treatments 2 and 3 compared to the other groups (P < 0.05). Investigation of complement, lysozyme, and serum bactericidal activity showed that probiotic treatments positively affected the immune system of common carp, with treatments 2 and 3 demonstrating a greater effect (P < 0.05). Biochemical factors were also investigated, showing decreased cholesterol and triglyceride levels in the probiotic treatment group. Moreover, the probiotic treatments resulted in a significant reduction in the activity of liver enzymes AST and ALP compared to the control group (P < 0.05).

 A probiotic combination with concentrations of 5 × 107 CFU g-1 and 5 × 108 CFU g-1 of food can positively impact common carp’s growth performance, immune system, and biochemical parameters. As no significant difference was seen between the two concentrations, the lower one is recommended.