Clam farmers in Taiwan are accustomed to using microbial preparations such as commercially available probiotics or photosynthetic bacteria for cultivation, but the impact of the use of microbial preparations on the overall microbial composition of the clam intestines is less discussed. This project useed a new sequencing technology to analyze The intestinal bacteria composition of clams, the clam feed is added to the freeze-dried bacterial powder D5 (Bacillus pumilus D5) developed by our institute. The intestinal samples of clams are taken at
regular intervals to extract DNA, and the bacteria 16S specific primers are used to amplify. Nanopore sequencing was used to analyze the overall bacterial composition of the clam intestine. Preliminary results showed that there was no significant reduction in Vibrio in the clam gut after 2 months of applying D5 (11.70%±8.40% before, 10.21%±10.09% after), and 16S sequence of Bacillus pumilus D5 was not found in sequencing results. Refer to previous studies, this situation may be due to the fact that D5 are less likely to survive in the clam guts than in white shrimp guts. When D5 bacteria are used to improve the culture of clams, longer casting time may be nessasary to achieve better results.