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

Abstract

Background: Probiotic bacteria as an alternative to antibiotics are necessary for aquaculture due to the prevalence of recurrent diseases. Objectives: 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. Methods: 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. Results: 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). Conclusions: 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.