Lactobacillus planarum subsp. plantarum JCM 1149 vs. Aeromonas hydrophila NJ-1 in the anterior intestine and posterior intestine of hybrid tilapia Oreochromis niloticus male x Oreochromis aureus female: An ex vivo study

摘要

To investigate the ex vivo interactions of probiotic-pathogen-host in warm-water fish, hybrid tilapia {Oreochromis niloticus male x Oreochromis aureus female) were sacrificed to isolate anterior and posterior intestine for incubation with phosphate-buffered saline (PBS; pH 7.2) as the control, Lactobacillus plantarum JCM 1149 at 1.0 x 10~9 CFU/ml, Aeromonas hydrophila NJ-1 at 1.0 x 10~8 CFU/ml, or the both combination. Denaturing Gradient Gel Electrophoresis (DGGE) fingerprint and consequent sequenceanalysis confirmed anterior intestine sac was more prone to the colonization of L plantarum JCM 1149 and A. hydrophila NJ-1 than the posterior part. L. plantarum JCM 1149 and A. hydrophila NJ-1 inhibited the population each other in anterior or posterior sac, indicating their competition for the colonization. The induced expression of HSP70, IL-1 beta and TNF-alpha in the anterior sac by the addition of L. plantarum JCM 1149 or A. hydrophila NJ-1 demonstrated the activity and a local immune response ofex vivo anterior sac. Compared with posterior intestine, higher population colonization and more sensitive immune response of anterior sac indicated differential patterns for the probiotic-pathogen-host interactions. Scanning electronic microscopy (SEM)observation showed that pathogen A. hydrophila NJ-1 damaged the anterior intestine, which was alleviated by the pretreatment of L. plantarum JCM 1149, showing its probiotic effect.