THE INTENSIVE CULTURE OF NILE TILAPIA SUPPLEMENTED WITH THE MICROALGAE Chlorella vulgaris IN A BIOFLOC SYSTEM

Abstract

The aim of this study was to evaluate the performance of Nile tilapia fingerlings cultured in biofloc technology using different inoculation densities of Chlorella vulgaris. The experimental design was completely randomized with biofloc system and four densities of Chlorella vulgaris (0, 2.5, 5 and 10 x 104 cell mL-1), each with four replications. The study lasted 63 days and was carried out in tanks with a working volume of 40L, at a stocking density of 10 fish per experimental unit and a mean initial weight of approximately 1.86 g. The water quality variables showed no significant difference between treatments, especially total ammonia nitrogen and nitrite nitrogen, which were within acceptable levels for culture of the species. The variables of zootechnical performance were not affected by the different inoculation densities of the microalgae, achieving a final mean weight of approximately 21 g for all treatments, and survival rates greater than 80%. The weekly inoculation densities of the microalgae Chlorella vulgaris therefore had no influence on the growth of tilapia fingerlings cultured in a biofloc system.

TILAPIA CULTIVATED IN A LOW-SALINITY BIOFLOC SYSTEM SUPPLEMENTED WITH <i>Chlorella vulgaris</i> AND DIFFERENTS MOLASSES APPLICATION RATES

“…The Zootechnical performance of Nile tilapia fingerlings was affected (p < 0.05) by molasses application rates and their interaction. However, the addition of microalgae C. vulgaris had no influence, as reported by Araújo et al (2019), when evaluating different densities of C. vulgaris (2.5, 5 and 10x10 4 cell mL -1 ) in the culture of tilapia in biofloc with stocking density lower than the present study (250 fish m -3 ), and found final weight of approximately 21 g and survival greater than 80%. The addition of C. vulgaris microalgae may not have influenced fish performance because it is already abundant in the culture system, as we found when evaluating the phytoplankton community, where C. vulgaris represented 55.99% (BFT-C30) and 57.54% (BFT-C50) in addition treatment, and 41.17% (BFT-30) and 44.89% (BFT-50) in treatments without addition.…”