The influence of different light wavelengths in the culture of the Pacific white shrimp Litopenaeus vannamei reared in BFT using LED lights

The Biofloc Technology Culture System (BFT System) allows production to be carried out in places such as ponds and greenhouses with plenty of natural lighting, as well as in closed environments such as sheds with artificial lighting. Indoor shrimp production systems or those that do not have an abundance of natural light during certain times of the year can benefit from the use of supplemental lighting. The objective of this study was to evaluate the influence of different wavelengths of light provided by LED lamps on water quality, microorganism community, and the zootechnical performance of Pacific white shrimp Litopenaeus vannamei reared in BFT system. The study was carried out in an indoor room with 15 tanks (120L), using a stocking density of 500 shrimp m-3 and an initial weight of 0.37 g. The experiment was designed with five treatments and three replications each, differing in the light wavelengths: green, blue, red, yellow, and white - control. Significant differences were found between the water quality parameters in nitrite, PAR (Photosynthetically active radiation) at all depths, light (Ix), and total amount of water used for production (p˂ 0.05). The green treatments showed a better nitrification process than the control treatment. The green treatment presented an overall higher abundance of microorganisms: significant differences were found in the abundance of bacteria such as free coccoid, free filamentous, attached filamentous, vibrio, and bacillus (p˂ 0.05); abundance of flagellates, ciliates, rotifers, and nematodes were also higher in the green treatment (p˂ 0.05). Furthermore, amoebas were not found in the green treatment, whereas presented a higher abundance in every other treatment (p˂ 0.05). Green treatment had higher final shrimp weight when compared to treatments with blue, yellow and white spectrum. Thus, only the green wavelength had a positive influence both on the water quality, as well as on the microorganisms and zootechnical performance of L. vannamei in the BFT system.