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Effects of Biofloc Reduction on Microbial Dynamics in Minimal-exchange, Superintensive Shrimp, Litopenaeus vannamei, Culture Systems

Authors

  • Andrew J. Ray,

    Corresponding author
    1. Waddell Mariculture Center, South Carolina Department of Natural Resources, 211 Sawmill Creek Road, Bluffton, South Carolina 29910, USA
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    • Present address: The University of Southern Mississippi, Gulf Coast Research Laboratory, 703 East Beach Drive, Ocean Springs, Mississippi 39564, USA.

  • Gloria Seaborn,

    1. Center for Coastal Environmental Health and Biomolecular Research, NOAA, 219 Fort Johnson Road, Charleston, South Carolina 29412, USA
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  • Luis Vinatea,

    1. Laboratório de Camarões Marinhos, Departamento de Aquicultura, Universidade Federal de Santa Catarina, CEP 88040-900, Florianópolis, Santa Catarina, Brazil
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  • Craig L. Browdy,

    1. Novus International, 5 Tomotley Ct., Charleston, South Carolina 29407, USA
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  • John W. Leffler

    1. Marine Resources Research Institute, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, South Carolina 29412, USA
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Corresponding author.

Abstract

The microbial community in minimal-exchange, superintensive culture systems should be managed to cycle nutrients and enhance production. This paper explores the effects of biofloc concentration reduction and a fish-free diet on several microbial community characteristics. In 16, 3.5-m diameter, 71-cm deep outdoor tanks, shrimp were stocked at 460/m3. Eight of the tanks received a fish-free, plant-based feed and eight received a conventional feed containing fishmeal and fish oil. Within each diet type, biofloc concentration was reduced in four of the tanks and was not reduced in the other four tanks. Photosynthetically active radiation (PAR) extinction coefficients, photosynthetic oxygen production, chlorophyll-a (chl-a) concentrations, pheophytin-a (pheo-a) concentrations, and the sum of odd and branched chain fatty acid concentrations as a bacterial abundance indicator (BAI) were measured. Biofloc reduction significantly (P≤ 0.003) decreased PAR extinction coefficients, chl-a concentration, pheo-a concentration, and BAI concentration, while significantly increasing photosynthetic oxygen production. Diet did not significantly affect (P > 0.05) any of these measured parameters. The observed changes in microbial community characteristics corresponded with, and may help to explain, significantly improved shrimp feed conversion ratios, growth rate, final weight, and biomass yield in the tanks with biofloc reduction.

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