Ingestion and depuration of polyester microfibers by Crassostrea gasar (Adanson, 1757).

The study aimed to obtain environmentally relevant microfibers (MFs) from polyester fabric and assess their impact on the oyster Crassostrea gasar. MFs were obtained by grinding the fabric, and their accumulation in oysters gills and digestive glands was analyzed after exposure to 0.5 mg/L for 2 and 24 h. Additionally, a 48 h depuration was conducted on the oysters exposed for 24 h. Sublethal effects were assessed in oysters exposed for 24 h and depurated for 48 h, using biomarkers like Catalase (CAT), Glutathione S-transferase (GST), and Glutathione Peroxidase (GPx), along with histological analyses. Polyester fabric grinding produced significant MFs (average length: 570 µm) with degraded surface and increased malleability. Oysters showed increased MF accumulation in digestive glands post-exposure, with no impact on antioxidant enzymes. Depuration decreased MFs accumulation. Histological analysis revealed accumulation in the stomach and brown cells, possibly indicating inflammation. This raises concerns about MFs bioaccumulation in marine organisms, impacting the food chain and safety.

Lippia sidoides essential oil at concentration of 0.25% provided improvements in microbiota and intestine integrity of Danio rerio.

The study evaluated the effects of dietary supplementation with Lippia sidoides essential oil on the microbiota and intestinal morphology of Danio rerio. For this, 448 fish were randomly distributed in 28 tanks divided into a control group fed a commercial diet without supplementation, a group fed a commercial diet containing grain alcohol and five groups fed a commercial diet containing essential oil of L. sidoides (LSEO) at concentrations of 0.25%, 0.50%, 0.75%, 1.00% and 1.25%. After the period of dietary supplementation, biological materials were collected for microbiological and histological analyses. There were no significant differences regarding the microbiological count between the groups. Diversity of the microbiome was higher in 0.25% group than in control group. LSEO inhibited the growth of potentially pathogenic bacteria. Fish fed LSEO0.25% showed greater intestinal histomorphometric indices. The inclusion of LSEO at 0.25% in the diet of D. rerio provided improvements in fish microbiota and intestine integrity.

O estudo avaliou os efeitos da suplementação dietária com óleo essencial de Lippia sidoides sobre a microbiota e a morfologia intestinal de Danio rerio. Para isso, 448 peixes foram distribuídos aleatoriamente em 28 tanques divididos em grupo controle alimentado com dieta comercial sem suplementação, grupo alimentado com dieta comercial contendo álcool de cereais e cinco grupos alimentados com dieta comercial contendo óleo essencial de L. sidoides (LSEO) em concentrações de 0,25%, 0,50%, 0,75%, 1,00% e 1,25%. Após o período de suplementação alimentar, foram coletadas amostras biológicas para análises microbiológicas e histológicas. Não houve diferenças significativas quanto à contagem microbiológica entre os grupos. A diversidade do microbioma foi maior no grupo de 0,25% do que no grupo controle. LSEO inibiu o crescimento de bactérias potencialmente patogênicas. Peixes alimentados com LSEO 0,25% apresentaram maiores índices histomorfométricos intestinais. A inclusão de LSEO a 0,25% na dieta de D. rerio proporcionou melhorias na microbiota e na integridade intestinal dos peixes.

Braga nasuta (Cymothoidae): an ectoparasite of the Giant Amazonian fish Arapaima gigas (Osteoglossidae) fingerlings cultured in the Amazon region in Northern Brazil / Braga nasuta (Cymothoidae): um ectoparasito de alevinos do peixe gigante da Amazônia Arapaima gigas (Osteoglossidae), cultivado na região Amazônica, no Norte do Brasil

Isopods Cymothoidae are organisms that parasitize several fish species, both marine and freshwater, provoking important physiological alterations and secondary infections. The genus Braga was proposed to harbor three species of parasitic isopods in freshwater fish from South America: B. brasiliensis, B. cichlae and B. nasuta. Posteriorly, other four species were included: B. patagonica, B. amapaensis, B. fluviatilis and B. bachmanni. Regarding the geographical distribution of the genus, there are registers in Brazil, Argentina, Suriname and Paraguay. In this study, 3,625 fingerlings of pirarucu Arapaima gigas were examined from a commercial fish farm in the Amazon region, Pará State, to observe and identify possible parasites. A total of eleven ectoparasitic isopods were carefully removed from the body surface of the hosts and fixed in alcohol 70%. They were processed and identified as Braga nasuta. Parasitological indexes were prevalence of 0.303%, mean intensity of 1.000±0.000 and mean abundance of 0.003±0.055. This is the first report of B. nasuta in pirarucu fingerlings.

Isópodes Cymothoidae são organismos que parasitam ampla variedade de espécies de peixes, tanto marinhos quanto dulcícolas, provocando importantes alterações fisiológicas e infecções secundárias. O gênero Braga foi proposto inicialmente para abrigar três espécies de isópodes parasitos de peixes de água doce da América do Sul: B. brasiliensis, B. cichlae e B. nasuta; posteriormente, outras quatro espécies foram inseridas: B. patagônica, B. amapaensis, B. fluviatilis e B. bachmanni. Em relação à distribuição geográfica das espécies deste gênero, há registros no Brasil, na Argentina, em Suriname e no Paraguai. Neste estudo, 3.625 alevinos de pirarucu Arapaima gigas de uma piscicultura comercial na região amazônica, Estado do Pará, foram examinados para observar e identificar possíveis parasitos. Ao total, foram encontrados onze isópodes ectoparasitos, cuidadosamente retirados da superfície corporal de hospedeiros e fixados em álcool 70%. Eles foram processados e identificados como Braga nasuta. Os índices parasitológicos tiveram prevalência de 0,303%, intensidade media de 1.000±0.000 e abundância média de 0,003±0,055. Este é o primeiro relato de B. nasuta em alevinos de pirarucu.