Improved gut environment of abalone Haliotis gigantea through Pediococcus sp. Ab1 treatment

This study demonstrated that host-derived Pediococcus sp. Ab1, a potential probiotic, can colonize the gut of abalone (Haliotis gigantea) for 12 days from cessation of feeding with Ab1-supplemented commercial diet. The effective colonization by Ab1 of H. gigantea fed a supplemented diet led to the alteration of microbial populations, increased in situ alginate lyase activity, and increased volatile short chain fatty acids (VSCFAs) production in the abalone gut. Vibrio halioticoli clade dominated the gut microflora of abalone fed an Ab1-supplemented diet, while other Vibrio species were dominant in the abalone fed an unsupplemented commercial diet alone. The same species of bacteria were found in the gut of abalone fed diet with and without supplementation; however, the representation of the V. halioticoli clade was much higher in the gut of abalone fed the Ab1-supplemented diet compared to the gut of abalone fed the unsupplemented commercial diet. The alginate lyase activity and production of formate, a VSCFA, were also higher in the gut of abalone fed the Ab1-supplemented diet compared to the gut of abalone fed unsupplemented commercial diet. These results indicate that the host-derived Pediococcus sp. Ab1 has significant potential as an effective probiotic, especially in the improvement of the gut microflora and nutrition status in abalone aquaculture.