Objective: We investigated the influence of Carnobacterium sp. Hg4-03 on intestinal microflora of the 4th instar Hepialus gonggaensis larvae, an economically important insect.
Methods: The effect was observed by molecular techniques based on the sequence of 16S rDNA V3 region gene and PCR/DGGE (Denaturing gradient gel electrophoresis). The health larvae were divided randomly into treatment group 1, treatment group 2 and control group, and fed on their natural food added with different amount of Carnobacterium sp. Hg4-03 (group 1 and group 2) or ddH2O (control). After 14 days and 28 days, 6 larvae from each group were randomly selected to be dissected and contents of guts were collected for bacterial diversity analysis.
Results: The result showed that bacterial diversity index of treatment groups with Hg4-03 was higher than control group, and the species of bacteria increased. Comparing the bands of DGGE profiles between three groups, the intensity of band stand for Carnobacterium sp. Hg4-03 have enhanced. Another band with swelled intensity found in profiles come from treatment group 2 after 28 d fed, the sequence analysis showed it belongs to Bacillus subtilis.
Conclusion: Feeding with Carnobacterium sp. Hg4-03 could balance the bacteria in larvae gut and increase bacteria diversity, that means the bacteria made a positive effect on the bacterial diversity of H. gonggaensis larval gut. Hg4-03 may be used as probiotic bacteria for rearing H. gonggaensis larvae in controlling conditions or the larvae's hemi-wild rearing.