Variation of the bacterial community in the biofloc culture system at different time scales

• Grant number: 24/11939-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: August 31, 2025
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Rodrigo Schveitzer
• Grantee: Julia Panula Valente
• Host Institution: Instituto do Mar (IMar). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

The Biofloc Technology (BFT system) is an intensive production system used for the culture of shrimp and fish. In this type of culture, dense microbial communities, which grow in the form of microbial flocs (bioflocs), are manipulated to control the ammonia released by the cultured organisms. This method of controlling nitrogen compounds allows cultivation to be carried out with minimal water exchange, increasing biosecurity. One variable that affects shrimp performance in biofloc culture is the composition of the bacterial community, and little is known about how it varies over different time scales. Given the dynamic nature of culture conditions in the BFT system (e.g., daily removal of bioflocs), changes in microbial composition may occur over a short time scale (e.g., 24 hours). Therefore, understanding the rate of succession of these microorganisms can help to understand how predictable the microbial community is in this system. In this project, the variation in the composition of the bacterial community will be studied over different time scales (daily and weekly). The samples to be analyzed were collected in an experiment that lasted 50 days. Shrimp of the species Litopenaeus vannamei were cultured under two different concentrations of bioflocs, expressed as total suspended solids: T500 (~ 500 mg L1) and T700 (~ 700 mg L1). Each experimental unit was stocked with 29 juveniles, representing a stocking density of 906 shrimp m3. Samples for bacterial analysis from each experimental unit were collected weekly. Additionally, between days 44 and 45 of cultivation, a sampling campaign was carried out over a 24-hour period (00:00 h, 08:00 h, 18:00 h, and 24:00 h).