Oral feed-based administration of Lactobacillus plantarum enhances growth, haematological and immunological responses in Cyprinus carpio

The effect of probiotic bacteria (Lactobacillus plantarum isolate FLB1) on the immunological responses of Cyprinus carpio (Common carp) was tested in a feeding trial. Fingerlings were divided into five treatment groups and fed with graded probiotic diets [@ 0 (T1), 10⁶ colony-forming unit (CFU)/g (T2), 10⁷ CFU/g (T3), 10⁸ CFU/g (T4), and 10⁹ CFU/g (T5) of test meal] in triplicate. Fish fed probiotic supplemented diets had significantly (P < 0.05) improved growth performance, haematological parameters, blood Haemoglobin (Hb), Total Erythrocyte Count (TEC), Total Leucocyte Count (TLC), Packed Cell Volume (PCV)/ Hematocrit (Ht), Mean Corpuscular Haemoglobin (MCH), and Mean Corpuscular Haemoglobin Concentration (MCHC), with the greatest improvement in the treatment T5. Significant (P < 0.05) increase in total serum protein and globulin, as well as lower Albumin (Alb)/ Globulin (Glb) ratio values were also reported. These values indicated the overall improvements in non-specific immune markers. In all the probiotic fed fish groups, significantly (P < 0.05) reduced values of blood glucose levels, total cholesterol, Triglycerides (TG), and High-Density Lipoprotein (HDL) were observed. Increased numbers of lactic acid bacteria (LAB) were detected in the gastrointestinal tract of probiotic-fed groups indicating the viability and survival of L. plantarum in the fish gut. The results showed that supplementing the diet with L. plantarum @ 10⁹CFU/g feed during the growth period of the fish in a semi-intensive culture system could improve growth and health status of C. carpio.