Several parameters influence the establishment of a BFT system and farmed animals’ performance. Aquaculture production systems with shrimp exposed to plenty of natural light may perform better than systems with low light levels due to the growth of photosynthetic microorganisms. Furthermore, the presence of light also positively influences the abundance of microorganisms, reflecting in the better performance of cultured shrimp. This research aimed to assess the impact of different green light photoperiods from LED lamps on water quality, microorganism community, antioxidant capacity (ACAP), lipid peroxidation (TBARS), and growth performance of the Pacific white shrimp P. vannamei in the BFT system. The study was conducted in the Shrimp Production Laboratory of the Institute of Oceanography of the Federal University of Rio Grande – FURG, Brazil. Trial was performed in 150L indoors tanks, using P. vannamei larvae with an initial weight of 0.48 g at a stocking density of 500 shrimp m-³. The experiment lasting 61 days and was designed with four treatments (four replicates), with different photoperiods using LED green light: 1) 16h LI/8h DA, 2) 12h LI/12h DA (control), 3) 8h LI/16h DA and 4) 4h LI /20h DA.
No significant differences were found in the water quality parameters, however, there were significant differences in the bacterial abundance of free coccoids, free filamentous, attached filamentous, vibrios, and bacilli (p ˂0.05) and in protozoa, such as flagellates, ciliates, rotifers, nematodes, and amoebae (p ˂0.05, Fig 1). There were also significant differences in lipid peroxidation (TBARS) with lower lipid peroxidation in the 12h LI/12h DA, 8h LI/16h DA, and 4h LI/20h DA treatments and higher antioxidant capacity (ACAP) in the hepatopancreas and muscle tissues in the 8h LI/16h treatment DA (p ˂0.05). In addition, shrimp from treatment 8h LI/16h DA showed a higher final weight than the control treatment 12h LI/12h DA (p ˂0.05).
The different photoperiods positively influenced the antioxidant capacity and oxidative damage (lipid peroxidation) and zootechnical performance. Results suggest that the photoperiod of 8 hours of green light and 16 hours of darkness can be recommended for rearing P. vannamei in biofloc system.