关键词: 植物乳杆菌, 黏附, 平板法测定, 肠内代谢

Abstract: To compare the metabolic status of exogenous Lactobacillus plantarum in the intestine of tilapia and zebrafish juvenile fish, tilapia or zebrafish juvenile fish were immersed with 104  cfu/mL, 105  cfu/mL, 106  cfu/mL, 107 cfu/mL Lactobacillus plantarum JCM1149 for 3 d and the whole intestines were sampled. In another experiment, tilapia or zebrafish juvenile fish were immersed with 107 cfu/mL Lactobacillus plantarum  JCM1149 for 7 d. The intestines were sampled at 0 h, 4 h, 12 h, 1 d, 2 d, 3 d, 4 d, and 5 d after immersion. The intestine samples were homogenized, and the absolute abundance of exogenous Lactobacillus plantarum in tilapia and zebrafish juvenile fish was evaluated by spread plate method and compared. The results indicated that after 3 d immersion, the absolute abundance of adhesive Lactobacillus plantarum in tilapia intestine did not change with the increasing immersion concentration above 105 cfu/mL, while the absolute abundance of adhesive Lactobacillus plantarum in zebrafish intestine was increased with the increasing immersion concentration up to 107 cfu/mL (P<0.05). After 7 d immersion, the levels of adhesive Lactobacillus plantarum decreased in both intestines of tilapia and zebrafish (P<0.01). Notably, the release of Lactobacillus plantarum was more rapidly in zebrafish, because one order of magnitude reduction in the level of intestinal Lactobacillus plantarum was observed at 24 h in tilapia, while 2 orders of magnitude reduction were observed at 24 h in zebrafish. These results indicated that variations existed in the metabolism of Lactobacillus plantarum in different fish hosts.

Key words: Lactobacillus plantarum, adhesive, plate counting, metabolism in intestine