Characteristics of Ammonia Removal and Nitrifying Microbial Communities in a Hybrid Biofloc-RAS for Intensive Litopenaeus vannamei Culture: A Pilot-Scale Study

Abstract

Ammonia is the main pollution factor of the aquatic environment in marine shrimp culture systems. In order to demonstrate the feasibility of the combination of biofloc technology and nitrifying biofilter for the ammonia removal, a 70-day production trial was conducted in a simplified pilot-scale hybrid biofloc-based recirculating aquaculture system (biofloc-RAS) with the intensive culture of Litopenaeus vannamei. Nitrogen dynamics and nitrifying microbial communities were investigated in three replicated systems simultaneously under the conditions of high feed loading and zero water exchange. Along with biofloc development in the culture tank and biofilm formation in the nitrifying biofilter during the trial, nitrification could be fastly and effectively established in the system, which was indicated by the dynamics of total ammonia nitrogen (TAN), NO2–-N, NO3–-N, and total nitrogen (TN) concentrations. Meanwhile, similar nitrifying microorganisms could be found between biofloc and biofilm, despite some differences in abundance, diversity, and composition of ammonia-oxidizing archaea and bacteria and nitrite-oxidizing bacteria. High TAN removal rate could be achieved and was significantly and positively correlated with abundances of these nitrifying microbial communities in both biofloc and biofilm, further indicating that both biofloc and biofilm could contribute highly to nitrification performance of the biofloc-RAS. The results of this study indicate a potential application of the biofloc-RAS in coastal intensive aquaculture.

Water quality assessment of East Kolkata Wetland with a special focus on bioremediation by nitrifying bacteria

“…Ammonia is considered as one of the pollutant that effects the shrimp production. Thus, to reduce the ammonia concentration in shrimp farm nitrifying microbial community was applied for better shrimp production (Xu et al 2020). Nitrifying bacteria along with lactobacillus is one of the best probiotic for enhancing fish production and maintenance of water quality parameters like temperature, DO, pH, ammonia, nitrite and nitrate (Karthik et al 2016).…”

“…as probiotics were found to be significant in maintaining the water quality properties and in reducing the load of pathogenic bacteria (Sunitha & Krishna 2016). Nitrifying microbial community has the ability for better fish production by promoting water parameters (Roalkvam et al 2020;Xu et al 2020). Therefore, the application of probiotics could effectively decrease the contaminant levels in water bodies, reducing the load of pathogenic microbes and enhance survival of aquatic animals.…”

Intensification of Penaeid Shrimp Culture: An Applied Review of Advances in Production Systems, Nutrition and Breeding

“…Depending on the environmental conditions, such as levels of suspended solids, microbial management, C:N ratio, N:P ratio, and control of light intensity, the hybrid system can be photoautotrophic-based (green-water RAS) or heterotrophic-based (BioRAS). In both cases, the chemoautotrophic community (nitrifying bacteria) is expected to develop either in separated compartments (e.g., biofilters) or by attaching to the suspended particles in the water column [83]. An initial water preparation step (e.g., inoculating mature biofloc water or addition of specific algae and bacteria species) is commonly employed [84].…”

Biofloc Technology (BFT) in Shrimp Farming: Past and Present Shaping the Future

“…Nowadays, after ∼20 years of evolution, BFT has been adapted and adjusted to different regions, locations, salinities, applied to one single-phase (nursery) or multiple phases, outdoor and indoor conditions, and according to different farm infrastructure, operational and resources limitations. The accumulated BFT knowledge has provided a baseline for the development of other related microbial-based (e.g., Aquamimicry, synbiotics, and semi-biofloc; Zeng et al, 2020;El-Sayed, 2021;Hussain et al, 2021), hybrid (e.g., BioRAS;Xu et al, 2020), and integrated (e.g., shrimp + fish) systems (Wright, 2015), with at least nine different variations. However, regardless of the system chosen and adopted, it is crucial to consider the local specificities (e.g., technological, social, financial, and environmental), tailoring day-to-day management practices and ongoing production strategies accordingly.…”