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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]

This work investigates the effect of adding different sources of organic carbon in biofloc systems on water quality, microorganisms' density and zootechnical performance of juvenile Mugil liza raised in the biofloc system indoors over 45 days. Fish (±7.99 g) were stored at a density of 15 fish per tank and fed a commercial feed of 42% protein. The study was arranged in three treatments according to the carbon source: dextrose—DE, liquid molasses—LM and rice bran—RB, and one control with no bioflocs (clear water—CW), all in triplicate. The treatments had no influence (p > 0.05) on the performance parameters of the animals, survival (over 90%), as well on the productivity (between 0.35 and 0.6 kg/m3). Overall mean of total ammonia was lower (p < 0.05) in the biofloc systems than in clear water (CW). Nitrite average was lower (p < 0.05) in the bioflocs fertilized with LM and RB carbon sources, having a concentration of 1.3 ± 1.9 mg/L and 0.6 ± 0.6 mg/L respectively. RB also had the smallest range in nitrite levels throughout the study, from 0.04 to 2.5 mg/L. The LM and RB provided a greater (p < 0.05) abundance of total adhered and coccus bacteria. Water consumption was higher (p < 0.05) in the CW (1.87 m3 per tank) compared with the biofloc treatments (0.41 and 0.44 m3 per tank). Liquid molasses contributed to maintaining water quality compared with clear water, providing savings of around 80% of water. [ABSTRACT FROM AUTHOR]

In this study Aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEN) occurrence in fish feed, regarding its chemical composition, were investigated. Besides, AFB1 bioaccessibility to fish was evaluated by in vitro digestion. Mycotoxins were extracted by QuEChERS and quantified by HPLC-FLD. Results showed that 93.3% of the samples were contaminated at maximum levels of 16.5, 31.6, and 322 µg/kg in the cases of AFB1, OTA, and ZEN, respectively. A positive correlation between OTA, ZEN contamination, and lipid content was observed. Risk estimation of feed consumption by fish at the highest levels of AFB1, OTA, and ZEN shows that the younger the fish, the higher the risk of exposure to mycotoxins. The AFB1 bioaccessibility assay showed that 85% of this mycotoxin may be absorbed by fish. Therefore, establishing maximum levels in the fishing sector is fundamental to contribute to feed quality and nutritional safety of fish species. [ABSTRACT FROM AUTHOR]

With the productive intensification of fish farming, the partial or total replacement of fishmeal by ingredients of plant origin became a reality within the feed industry, with the aim of reducing costs. However, this practice increased the impact of mycotoxin contamination. Studies have shown that mycotoxins can induce various disorders in fish, such as cellular and organic alterations, as well as impair functional and morphological development, and, in more severe cases, mortality. Thus, studies have been conducted to evaluate and develop strategies to prevent the formation of mycotoxins, as well as to induce their elimination, inactivation or reduction of their availability in feed. [ABSTRACT FROM AUTHOR]

Abstract: Nutritional values of microbial floc meal and soy protein concentrate were evaluated as alternative protein sources to fishmeal in diets for Litopenaeus vannamei juveniles. A feeding trial was conducted during 28days to investigate the effects of partial and total replacement of fishmeal with microbial floc meal and soy protein concentrate on feed intake and growth of L. vannamei. Five diets were formulated to contain 38% crude protein and 17kJ/g gross energy. Microbial floc meal was obtained from super-intensive shrimp farm effluent. A control diet (with fishmeal as the main protein source) was compared to four diets containing microbial floc meal and soy protein concentrate at 25%, 50%, 75% and 100% replacement levels and a commercial diet. This feeding trial was conducted in a recirculating aquaculture system, utilizing shrimps weighing 2.48±0.29g. The weight gain, final weight, feed conversion ratio, specific growth rate, protein efficiency ratio and survival were not significantly different among treatments, suggesting that fishmeal can be completely replaced with soy protein concentrate and microbial floc meal without adverse effects on L. vannamei performance. These results suggest that a mixture of soy protein concentrate and microbial floc meal can be utilised as a substitute for fishmeal in diets for L. vannamei juveniles. [Copyright &y& Elsevier]