Use of Lactobacillus for Improved Growth and Enhanced Biochemical, Hematological, and Digestive Enzyme Activity in Common Carp at Mazandaran, Iran

The aim of this study was to investigate the effects of Lactobacillus plantarum strain 44A doses on growth performance, feed utilization, blood serum parameters, and digestive enzyme activities in Common Carp Cyprinus carpio fingerlings. This bacterium was isolated from healthy Striped Mullet Mugil cephalus. Lactobacillus plantarum was added to the diet in three levels (1.5x10(6), 3x10(6), and 4.5x10(6) colony-forming units [CFU]/mg of feed). A control diet was used as a reference. The results indicated that feed conversion ratio (FCR), specific growth rate, daily growth coefficient, protein efficiency ratio, condition factor, thermal-unit growth coefficient, and survival rate of Common Carp fingerlings were best for the treatment group fed with L. plantarum at the 4.5x10(6) CFU/mg level. In general, all L. plantarum treatments had better hematological parameters relative to the control, including red blood cell count, total leucocytes, hematocrit, hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration. A significant increase in the total protein and globulin concentration in blood serum was found in all probiotic-treated fishes compared with the control group, whereas no significant difference was observed in albumin levels. Other observed changes included lower cortisol and glucose contents in serum blood from probiotic-treated fingerlings than in the control group. Serum lysozyme activity was also considerably greater in fish fed a higher level of L. plantarum compared with the control fish. Mean protease and amylase activities of all probiotic treatment groups were significantly higher than those in the control fish. There was no significant difference in lipase level. In conclusion, the improved enzyme activities obtained with the L. plantarum diets suggest that the addition of probiotics improved diet digestibility, including protein, starch, and fattiness, and resulted in better growth performance and feed efficiency (FCR) in Common Carp.