Identification of the bacterial composition in the rockworm gut and biofloc-fed adult gut flora beneficial for integrated multitrophic aquaculture

Abstract

The rockworm gut flora was identified at each growth stage to elucidate the composition of the bacterial community. The source material was Marphysa sanguinea fed regular feed and fed biofloc at the adult stage in parallel. The systematic bacterial community composition was determined based on the next-generation sequencing method, and alpha diversity and beta diversity were conducted to access the species diversity within and between the bacterial communities, respectively. The composition of the gut flora changed considerably as the rockworms developed. The shift in the gut flora was confirmed at the phylum, family, and genera level of the bacterial communities. The Vibrio species associated with high rockworm mortality occupied 7.7% of the gut flora at the larval stage; however, they disappeared in the healthy adult gut. Moreover, different gut flora was observed between adults fed regular feed and those fed biofloc. Specifically in the biofloc-fed adult gut, several immune relevant and water-purifying bacteria were detected. The biofloc-fed adult gut flora could decompose and mineralize organic sediment, and thus be effectively utilized for integrated multitrophic aquaculture. The Venn diagram revealed that only two bacterial species were shared throughout all growth stages, and the biofloc-fed adults exhibited the highest diversity within the bacterial community.

Isolation and molecular identification of proteolytic bacteria from vaname shrimp (Lithopenaeus Vannamei) ponds as probiotic agents

“…Pseudoalteromonas sp. is one bacteria that can adapt and thrive in the digestion of shrimp and sea eels (58,59). This bacterium is likely to have activity as a probiotic agent because it has several metabolic products used in aquaculture.…”

“…Furthermore, the bacterial species producing proteolytic activity were abundantly isolated from the water (41), sediment, shrimp gut, agricultural waste (42), and intestinal worms (59). Besides having good proteolytic activity, Pseudoalteromonas ganghwensis WAB2121 also had antivibrio, certifying its suitability in maintaining the balance of aquacultural environments, especially vannamei shrimp culture.…”