Abstract
Biofloc technology (BFT) is one of the most promising technologies in global aquaculture for the purpose of improving water quality, waste treatment, and disease prevention in intensive aquaculture systems. However, characterization of the microbial species and antibiotic resistance potentially present in biofloc-based aquaculture environments is needed. In this study, we used high-throughput sequencing technology to comprehensively compare the bacterial communities in mariculture ponds of Penaeus monodon (P. monodon), by testing of water, biofloc, and intestine of P. monodon. Operational taxonomic units (OTUs) cluster analysis showed that the nine samples tested divided into 45 phyla and 457 genera. Proteobacteria was the dominant bacteria in water, biofloc and prawn intestine. In biofloc and intestine, the Ruegeria (2.23–6.31%) genus represented the largest proportion of bacteria, with Marivita (14.01–20.94%) the largest group in water. Microbial functional annotation revealed that in all the samples, genes encoding metabolism were predominant. The antibiotic resistance gene annotation showed the highest absolute abundance of patB, adeF, OXA-243, and Brucella_suis_mprF from Proteobacteria. PatB (11.33–15.01%), adeF (15.79–18.16%), OXA-243 (35.65%), and Brucella_suis_mprF (10.03%) showed the highest absolute abundance of antibiotic resistance genes in water, biofloc, and intestines, respectively. These findings may greatly increase our understanding of the characteristics of the microbiota of shrimp biofloc-based aquaculture systems and the complex interactions among shrimp, ambient microflora, and environmental variables. It provides a reference basis for policy on breeding, environmental safety, and maintaining food safety in the production of P. monodon.
Highlights
With the pollution of the marine aquatic environment and the decline of the wild fishing industry, aquaculture plays an increasingly important role in the sustainable supply of food
This study provides data to support future improvements of the biofloc-based aquaculture system of P. monodon, which will inform the policies of breeding, environmental safety, and assist in maintaining food safety for this valuable species
The genomic DNA of water, biofloc, and intestinal samples was extracted by the cetyltrimethylammonium bromide (CTAB) method (Khalid et al, 2021) and the purity and concentration of DNA was measured by agar gel electrophoresis
Summary
With the pollution of the marine aquatic environment and the decline of the wild fishing industry, aquaculture plays an increasingly important role in the sustainable supply of food. Penaeus monodon (P. monodon) (giant tiger shrimp) aquaculture accounts for a significant proportion of seafood consumption and is the second most farmed variety of shrimp worldwide (FAO, 2020) Bacterial diseases such as death by early mortality syndrome (EMS), acute hepatopancreatic necrosis disease (AHPND), and hepatopancreatic necrosis syndrome (HPNS) have reduced shrimp production by nearly 40%, resulting in global losses of over 1 billion dollars per year for shrimp aquaculture (Flegel, 2012; Lee et al, 2015; Huang et al, 2016). A biofloc-based aquaculture system is a microbial treatment based on the composition of abundant microflora In this system, chemoautotrophic and heterotrophic bacteria are involved in the formation of biofloc, which include fungi, protozoa, zooplankton, and microalgae, which decompose food remnants and animal waste, remove excess ammonia and nitrogen from the water, and maintain a stable nutrient level (Yoram, 1999; Wei et al, 2020). Biofloc technology (BFT) cannot only enhance growth performance of an organism, elevate digestive enzyme activity, and strengthen antioxidant status, and has been shown to improve immune response through the probiotic and immunostimulant effects of the microorganisms present in the biofloc (Yu et al, 2020)
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