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The growth of aquaculture demands intense consumption of formulated foods, scarce natural resources such as water and land. The increase in aquaculture production needs to be sustainable in several aspects of the activity, including the use of more sustainable farming systems that provide reduced water demand, less space dependence for increased production, and availability of complementary natural food. In this perspective, the biofloc system (BFT), presents itself as a more friendly cultivation technology as a way to mitigate some impacts of aquaculture production. Much research has been carried out, addressing different aspects important to the production of fish in BFT. In this review, we address how stocking density, carbon sources and carbon nitrogen ration (C/N) affect animal performance and the nutritional value of bioflocs; the use of microbial aggregates as "in situ" and "ex situ" food and the benefits in feed conversion, and their influence on the immune system and disease resistance. [ABSTRACT FROM AUTHOR]

The effects of cyclical feeding restriction (3, 4, 5, 6, and 7 days of feeding per week) on the performance of juvenile Nile tilapia (Oreochromis niloticus) in a biofloc technology system (BFT) were evaluated in this study for 77 days. Fifteen experimental units (400L) with temperature control (mean 28.2 °C) randomly distributed 1500 fish (0.42 ± 0.02 g). Fish were fed commercial feed (46.7 g of crude protein and 4475.5 kcal kg−1 of gross energy) up to satiation. Feeding cycles with different restrictions (p < 0.05) influenced animal growth but not survival and final density (p > 0.05), which remained around 94% and 235 fish.m−3, respectively. Juveniles fed 6 days a week showed 1.25 of feeding efficiency, while animals fed 3 days a week (more restricted) showed hyperphagia but did not exhibit compensatory growth. Changes in the morphology of hepatocytes (presence of vacuoles, displacement of the nucleus to the periphery, and fatty degeneration) were observed with an increase in feeding days, and a high degree of hepatic steatosis (p < 0.05). Water quality parameters remained within acceptable limits for the species and system operation. Feeding regimes influenced the characteristics of bioflocs (total suspended solids and porosity) and the abundance of microorganisms (p < 0.05). Nutritionally, less restricted diets (6 and 7 days of feeding per week) produced more protein (38.3 and 40.6% CP) and energy bioflocs (2252.8 and 2313 kcal.kg−1) (p < 0.05), while protein, lipid, and body energy were significantly lower (p < 0.05) with the more restricted diet. The composition of microorganisms was influenced by the feeding regimes (p < 0.05). Results demonstrated that the occurrence of total compensatory growth (6 days of feeding per week) represents an economic advantage with a reduction of 26.8% of feed and greater profitability in the unitary commercialization of tilapia juveniles. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of the feeding rate (0%, 2.5%, 5.0%, 7.5%, and 10% of body weight per day; BW.d−1) on growth performance, nutritional efficiency, and profitability of Nile tilapia (Oreochromis niloticus) juveniles (3.1 ± 0.1 g) using the biofloc technology (BFT) system for 70 days. Fish were randomly stocked (15 fish. Tank−1) in 24 experimental units (50 L), while water quality parameters remained within acceptable limits for the species during the experiment. Animal performance parameters were influenced by feeding rates (P < 0.05), but not survival (P > 0.05), which remained around 81%. Final body weight, weight gain, and thermal growth coefficient increased significantly (P < 0.05); however, the gradual increase in feeding rates had reduced feed efficiency, protein, and energy productive values (P < 0.05). Whole-body lipid and gross energy increased significantly (P < 0.05) as the feeding rate increased, while the moisture content showed an opposite trend up to 5.0% BW.d−1. The results show that Nile tilapia juveniles raised in the BFT system should be fed between 4.3 and 6.1% BW.d−1 to exhibit improved profitability and growth. • Optimum feeding rate in nursery phase (3–30 g) of Nile tilapia reared in a BFT system is 6.1% BW.day−1. • From an economic viewpoint 4.3% BW.day−1 is recommended for tilapia juveniles in a BFT system. • Nile tilapia juveniles can be strategically maintained for 70 days while feeding only on bioflocs. • After 70 days of feeding only on bioflocs tilapia growth was equivalent around 20% than that of fish fed 6.1% BW.day−1. [ABSTRACT FROM AUTHOR]