1- Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran 2- Department of Livestock, Poultry and Aquatic Animal Health, Shahid Chamran University of Ahvaz, Ahvaz, Iran , t.mohammadian@scu.ac.ir 3- Department of Livestock, Poultry and Aquatic Animal Health, Shahid Chamran University of Ahvaz, Ahvaz, Iran 4- Member of Excellence Center of Warm Water Fish Health, Shahid Chamran University of Ahvaz, Ahvaz, Iran 5- Department of Clinical Science, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
Abstract: (15 Views)
In this study, two probiotics (Citrobacter freundii and Bacillus foraminis) with indigenous quorum quenching (QQ) were isolated from the intestine of Cyprinus carpio and their effects on hemato-serological parameters and innate immune responses, antioxidant capacity and disease resistance in C. carpio were determined. The juveniles (n=450, 50.26±10.47 g mean weight) were randomly divided into 6 groups (with 3 replications) and fed with diets containing 1×109 cfu g-1 of C. freundii (QQ1, G1), B. foraminis (QQ2, G2), Lactobacillus plantarum (without characteristics QQ, WQQ, G3), QQ1+QQ2 (G4), QQ1+QQ2+WQQ (combine, G5), and a control diet (without probiotic) for 60 days. The hematocrit level was increased in the fish fed with QQ1 and WQQ supplemented diets compared to the control group. At 30 days, the combined probiotic treatments (QQ1+QQ2+WQQ) significantly increased hemoglobin and total leukocyte count compared to QQ1 and control, though these differences were not observed at 60 days. QQ2 notably improved complement activity and lysozyme levels after 30 days, while QQ1+QQ2 showed a higher antitrypsin activity at 30 days. The myeloperoxidase levels were elevated in the combined treatments at 60 days. The hepatic catalase activity was higher in QQ probiotic groups at 30 days but it was decreased by 60 days with significant differences noted between WQQ and other groups. The highest superoxide dismutase activity was obtained in QQ2 at 30 and 60 days. The liver glutathione level was decreased in the mixed probiotic groups but it was increased in the combined group at 60 days. A lower content of malondialdehyde was in QQ1 and QQ2 groups at 60 days. The probiotic-treated groups showed significantly lower mortality rates compared to the control against A. hydrophila infection, with the highest mortality occurring 30 hours post-infection [G1 (30.6%), G2 (30.6%), G3 (40.63%), G4 (30.6%), G5 (40.63%), and the control group (60.3%)]. Overall, the indigenous probiotics cause an improvement in various health parameters and could reduce mortality rates in infected fish.