Effect of probiotic Lactococcus lactis (PTCC 1403) and chitin on blood and serum biochemical parameters and intestine bacteria of Common carp (Cyprinus carpio)

The aim of the current study was to evaluate the effect of dietary Lactococcus lactis subsp. lactis and chitin on blood and serum biochemical parameters and intestine bacteria of common carp. To do the experiment, 360 juvenile carp with mean initial weight of 12±1.5 g were randomly distributed in the fiberglass tanks designed based on different levels of chitin 0, 1 and 2% and probiotic 0 and 2% (1 ×10⁷CFU/g) in diet and the experiment lasted for eight weeks. The experimental treatments were including control (treatment 1), probiotic 2% (treatment 2), chitin 1% (treatment 3), chitin 2% (treatment 4), probiotic 2% + chitin 1% (treatment 5) and probiotic 2% + chitin 1% (treatment 6). On the end of the experiment, blood parameters including red blood cell (RBC), Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hemoglobin (Hb), hematocrit (HCT), white blood cell (WBC), lymphocyte, eosinophil and monocyte, serum biochemical parameters including total protein, albumin, glucose, cholesterol, triglyceride and intestinal bacterial colony were determined. The results showed that RBC, MCV, MCH, MCHC, Hb, HCT, thrombocyte, monocyte had no significant difference among treatments (p>0.05), But, maximum level of WBC in treatments 5 and 3 (18.03±1.66, 16.86±1.49 10³ mm³, respectively), lymphocyte in treatments 5 and 2 (70.40±4.58, 65.00±2.65, respectively) and eosinophil in treatments 3 and 6 (2.67±1.16, 1.67±0.58, respectively) were observed. Biochemical parameters showed no significant difference among experimental treatments and control, but, there were significant difference among the diets containing probiotic and chitin or/and a mixture of probiotic and chitin (p<0.05). The intestinal bacterial colony in all treatments except treatment 6 was more than the control (p<0.05). The maximum bacterial colony count was observed in treatment 4 (653.33±25.17 CFU/g). In conclusion, it seems the addition 2% probiotic, 1% chitin and a mixture of them can improve white blood cells and intestinal bacterial colony in common carp.