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This study aimed to evaluate the apparent digestibility coefficients (ADCs) of dry matter, crude protein, gross energy, and minerals of marine fish meal (MFM), salmon meal (SM), tilapia by-product meal (TBM), meat and bone meal (MBM), poultry by-product meal (PBM), blood meal (BM), and feather meal (FM) by silver catfish Rhamdia voulezi. Groups of 12 fish were fed the experimental diet three times a day until apparent satiation, and the fecal samples were collected from an accumulation device. SM and PBM exhibited the highest digestibility values for dry matter, crude protein, and gross energy, while MBM and FM presented significantly lower ADCs for dry matter. BM and FM exhibited higher ADCs for phosphorus, 65.05 and 63.87%, respectively. The ADCs for calcium were 58.8% for MFM, 56.69% for TBM, and 60.08% for PBM. PBM and FM had the highest iron ADCs, 44.01 and 46.29%, respectively. Magnesium ADCs ranged from 44.87% for MBM to 75.50% for TBM. BM had the highest digestibility for zinc (62.77%), whereas MBM (36.68%) and FM (39.39%) had the lowest. In general, SM and PBM showed higher values as feedstuffs for silver catfish feeds. At the same time, the digestibility was lower for TBM and MBM for macronutrients and minerals such as phosphorus, iron, and zinc.

Gradually, concern for the welfare of aquatic invertebrates produced on a commercial/industrial scale is crossing the boundaries of science and becoming a demand of other societal actors. The objective of this paper is to propose protocols for assessing the Penaeus vannamei welfare during the stages of reproduction, larval rearing, transport, and growing-out in earthen ponds and to discuss, based on a literature review, the processes and perspectives associated with the development and application of on-farm shrimp welfare protocols. Protocols were developed based on four of the five domains of animal welfare: nutrition, environment, health, and behaviour. The indicators related to the psychology domain were not considered a separate category, and the other proposed indicators indirectly assessed this domain. For each indicator, the corresponding reference values were defined based on literature and field experience, apart from the three possible scores related to animal experience on a continuum from positive (score 1) to very negative (score 3). It is very likely that non-invasive methods for measuring the farmed shrimp welfare, such as those proposed here, will become a standard tool for farms and laboratories and that it will become increasingly challenging to produce shrimp without considering their welfare throughout the production cycle.

The Itaipu Hydroelectric Power Plant is the second largest in the world in power generation. The artificial barrier created by its dam imposes an obstacle for fish migration. Thus, in 2002, a fish pass system, named Piracema Channel, was built to allow fish to access areas upstream of the reservoir. We tested the potential of environmental DNA metabarcoding to monitor the impact of both the dam and associated fish pass system in the Paraná River fish communities and to compare it with traditional monitoring methods. Using a fragment of the 12S gene, we characterized richness and community composition based on amplicon sequence variants, operational taxonomic units, and zero-radius OTUs. We combined GenBank and in-house data for taxonomic assignment. We found that different bioinformatics approaches showed similar results. Also, we found a decrease in fish diversity from 2019 to 2020 probably due to the recent extreme drought experienced in southeastern Brazil. The highest alpha diversity was recorded in the mouth of the fish pass system, located in a protected valley with the highest environmental heterogeneity. Despite the clear indication that the reference databases need to be continuously improved, our results demonstrate the analytical efficiency of the metabarcoding to monitor fish species.

Integrated production (IP) is a relatively new production regime that supports environmental, labor, and management issues through the production process. As the marine shrimp farming in Brazil has been recently impacted by environmental and sanitary issues, IP principles could provide tools to improve the productivity in a systemic method. Our goal was to compare a hypothetical IP shrimp farm with the conventional cultivated marine shrimp production (CP) and identify possible challenges that IP would face if adopted as an alternative production regime for the Brazilian shrimp farming scenario. IP and CP data were obtained through application of PRISMA (preferred reporting items for systematic reviews and meta-analyses) methodology and the comparison was conducted through a strength, weakness, opportunity, and threat (SWOT) analysis and based on concepts derived from the Delphi methodology. The results indicate that the major challenges for IP in Brazil are as follows: (i) the absence of specific technical standards (STS) for the certification of shrimp farms, (ii) the possibility of increasing investment costs for implementation and operation of certified farms, and (iii) non-differentiation in the internal market of certified and non-certified products. Conversely, IP introduces significantly superior forces than CP. The most important of these forces are (i) the adoption of a systemic view of the productive chain, (ii) the traceability of products and processes, (iii) the reduction of barriers to environmental licensing of aquaculture farms, (iv) the reduction of risks and damages caused by diseases, and (v) the optimization in the use of natural resources, inputs, and energy.

Water salinity is among the most important factors influencing the distribution, abundance, growth, and survival of Crassostrea gasar, an important aquaculture resource grown in estuarine environments in diverse regions of the world. The goal of the present work was to evaluate the effects of different salinities on survival and the tissues of C. gasar under laboratory conditions. Two experiments were performed using adult oysters from five marine farms located in the bay of Guaratuba, Brazil. In Experiment 1, the daily survival rates were evaluated after the oysters were submitted to gradual acclimatization at salinities ranging from 0 to 65 gL-1 and maintained in the laboratory without feeding for up to 365 days. In Experiment 2, the oysters were exposed to salinity from 0 to 50 gL-1 for up to 30 days without feeding and possible histological alterations caused by salinity were assessed. Three tolerance ranges of C. gasar to salinity were identified: "Optimal" (between 4 and 40 gL-1), "Tolerable" (between 2.1 and 3.9 and between 41 and 50 gL-1) and "Intolerable" (less than 2 and greater than 50 gL-1). No evidence of histological alterations was observed in oysters exposed to the different salinities. A salinidade da água está entre os fatores de maior influência na distribuição, abundância, crescimento e sobrevivência de Crassostrea gasar, um importante recurso aquícola cultivado em ambientes estuarinos em diversas regiões do mundo. O objetivo desse trabalho foi avaliar os efeitos da salinidade sobre a sobrevivência e nos tecidos de C. gasar exposta a diferentes salinidades, em condições laboratoriais. Foram realizados dois experimentos com ostras adultas provenientes de cinco fazendas marinhas localizadas na baía de Guaratuba, Brasil. No experimento 1, que foi realizado com o propósito de avaliar as taxas diárias de sobrevivência, as ostras foram submetidas à aclimatação gradual a salinidades variando de 0 a 65 gL-1 e mantidas em laboratório, sem alimentação, por até 365 dias. No experimento 2, as ostras foram expostas a salinidades de 0 a 50 gL-1 por até 30 dias, sem alimentação, para avaliação de possíveis alterações histológicas provocadas pela salinidade. Foram identificadas três faixas de tolerância de C. gasar à salinidade: Ótima (entre 4 e 40 gL-1), Tolerável (entre 2,1 e 3,9 e entre 41 e 50 gL-1) e Intolerável (menor que 2 e maior que 50 gL-1). Não foram encontradas evidências de alterações histológicas em função da exposição das ostras às diferentes salinidades.

AIMS To evaluate the influence of storage conditions on the composition of the bacterial microbiota of living oysters Crassostrea gasar. METHODS AND RESULTS The oysters used in this study came from marine farms (Guaratuba Bay, Brazil) and were exposed to two conditions that simulated different storage situations: immersion in water (group I) and exposure to air (group II). The animals were subjected to five different temperatures (5-25°C), for 10 days. The 16S rRNA gene from oysters was amplified and sequenced to determine the taxonomic units and bacterial strains present in the samples. Group I showed higher diversity of bacteria (163 genera) rather than group II (104 genera). In all, 59 bacterial genera potentially pathogenic to humans were identified (n = 56 in group I and n = 45 in group II). CONCLUSIONS The storage conditions having a direct influence on the oyster microbiota. Live C. gasar should be stored exposed to air at 5-25°C, because it favours a lower prevalence of bacteria potentially pathogenic to humans. SIGNIFICANCE AND IMPACT OF THE STUDY During the oyster commercialization process, some conditions of storage, time and temperature must be followed in order to reduce the prevalence of bacteria potentially pathogenic to humans.