A realistic combined exposure scenario: effect of microplastics and atrazine on Piaractus mesopotamicus.

Microplastics, considered emerging environmental contaminants resulting from plastic degradation, are discovered in diverse aquatic ecosystems and can be unintentionally ingested by fish. Therefore, it is essential to characterize their interaction with other contaminants, such as agrochemicals, in aquatic environments. This study aimed to assess histological, enzymatic, and genotoxic biomarkers in juvenile pacú (Piaractus mesopotamicus) exposed to polyethylene (PE) microplastic particles and the herbicide atrazine, individually or combined, for 15 days. Four treatments were used: a negative control (CON), PE in the fish diet (0.1% w/w, FPE), atrazine through water (100 µg L-1, ATZ), and the mixture (ATZ+FPE). Results confirmed histological alterations in gills (edema and lamellar fusion) and liver (necrotic areas and congestion) of fish exposed to ATZ and ATZ+FPE. The number of goblet cells increased in the posterior intestine of fish under ATZ+FPE compared to CON and FPE. Enzyme activities (CAT, GST, AChE, and BChE) significantly increased in ATZ+FPE compared to CON. However, no genotoxic effect was demonstrated. These findings provide insights into the complex impacts of simultaneous exposure to atrazine and microplastics, emphasizing the need for continued research to guide effective environmental management strategies against these contaminants that represent a risk to aquatic organisms.

Hepatic encephalopathy in swine experimentally poisoned with Senna occidentalis seeds: Effects on astrocytes.

Senna occidentalis may be accidently ingested by humans and animals. In this study, the percentages of S. occidentalis seeds necessary for experimental reproduction of hepatic encephalopathy were determined in a pig model and the biochemical and microscopic pathology is described in detail, with emphasis on the astrocytes. The experimental groups (G1, G2 and G3) were fed rations containing 5%, 7.5% and 10% of S. occidentalis seeds for 7-11 days. Pigs from the three experimental groups showed incoordination, ataxia, disorientation, head pressing, anorexia, recumbency and depression. In addition, the enzymes aspartate aminotransferase, alkaline phosphatase and creatine phosphokinase increased in all treated animals, which also showed higher serum total bilirubin and ammonia levels than in the control group (C). Microscopically, all experimental animals revealed acute hepatocellular swelling, multifocal coagulative necrosis in the pancreas, necrosis in the cardiac muscle, severe spongiosis in brain white and grey matter, and Alzheimer type II astrocytes in grey matter of the cerebral cortex. These cells were glial fibrillary acidic protein (GFAP) negative in G3. In white matter, a decrease in the positive area occupied by GFAP-immunolabelling and in the number of astrocytes per immunoreactive area was observed in G3 animals (5.35 ± 1.14% and 410 ± 45 cells/mm2, respectively) compared to the C animals (13.93 ± 1.59% and 581 ± 36 cells/mm2, respectively). This loss of GFAP was accompanied by alterations in astrocyte morphology, such as shrinkage of the cell body and retraction of the extending processes. This pig model of ammonia-mediated astrocyte damage could be used to study not only poisoning by S. occidentalis, but also other medical conditions resulting in hepatoencephalopathy.

Sensory and instrumental textural changes in fillets from Pacú (Piaractus mesopotamicus) fed different diets.

The influence of two dietary treatments on quality properties, like textural parameters, sensory profile, and nutritional composition of Pacú fillets (Piaractus mesopotamicus) were studied. Pacú were fed diets based on plant-meals containing 13 g 100 g-1 fish meal (FMD) or bovine plasma protein concentrate (BPPD) as a complete replacement of fish meal. Harvested fish were filleted, kept frozen at -20C for 7 days before analysis. Chemical composition, amino acid and fatty acid profiles, and CIE-Lab parameters of fillets were measured. Sensory characteristics and texture profile analysis (TPA) were conducted for cooked portions. Average values of TPA hardness, chewiness, and deformability modulus were higher in BPPD samples but there was no significant difference in cohesiveness between samples. In accordance with TPA, higher values of firmness and chewiness as well as less flaky muscle were detected in BPPD samples by sensory panel. However, there was no significant difference in the characteristics associated with higher freshness between samples. Total color difference was lower in BPPD samples. Differences in protein, lipid, ash, and moisture content of FMD or BPPD fillets were not found (p > .05). BPPD fillets showed higher basic and sulfur amino acids. Saturated and polyunsaturated fatty acid contents were higher in FMD fillets than BPPD. However, a significantly higher n-6/n-3 ratio for FMD fillets was observed. The higher values of textural parameters observed for BPPD cooked fillets and the lower n-6/n-3 ratio imply a better sensory and nutritional quality of fillets from fish fed with BPPD. PRACTICAL APPLICATIONS: A complete study is presented on how the source of protein and lipids in feed affect both the sensory profile and the nutritional composition of fillets of Pacú (omnivorous temperate freshwater fish) cultivated in the second stage of fattening. Instrumental texture analysis of the fillets is presented, identifying the indicators that match with sensorial analysis. This analysis can help the industry of aquaculture in the evaluation of new ingredients or diets for fish feeding with impact in the quality of fillets.

Development of the vertebral column and caudal skeleton in Prochilodus lineatus larvae under laboratory conditions / Desarrollo de la columna vertebral y del esqueleto caudal en larvas de Prochilodus lineatus en condiciones de larvicultura intensiva

For successful fish larviculture thorough studies describing the development of fish in different morphological aspects are required, as they are crucial for larval survival and growth. The present study described in Prochilodus lineatus larvae the osteological development of the vertebral column and caudal skeleton 30 days after hatching (dah). Larvae were obtained by artificial induction of adults. The beginning of formation of the spine occurs between 10 to 12 dah (8.3 mm standard length, SL) simultaneously to the first neural and hemal processes and the pre-caudal vertebral bodies. The ossification of the vertebral column occurred in cranio-caudal direction and was completed at 28 dah (22.6 mm SL). The development of the caudal skeleton elements started between 6 and 8 dah with the formation of the hypurals (H), the parahipural (PH) and the primary and secondary caudal rays. H 1 to H 3 were formed as cartilaginous primordia on the ventral side of the distal portion of the notochord, while the PH and H 4 to H 6 were formed subsequently. The first rays of the caudal fin were observed in correspondence with the formation of H 2 and H 3, while complete formation of the caudal fin was observed at 28 dah. The epurals, three in number, were evident as cartilaginous elements located both dorsal and distal in the notochord. Central ural complex (CUC) was formed by the fusion of three structures, the center preural 1 and urals 1 and 2. Development of the vertebral column and the caudal skeleton in P. lineatus larvae showed similar patterns to those described for other teleosts.

Se describe el desarrollo osteológico de la columna vertebral y del esqueleto caudal en larvas de sábalo (Prochilodus lineatus) bajo condiciones controladas hasta los 30 días posteriores a la eclosión (dpe). El inicio de la formación de la columna vertebral fue observado entre los 10-12 dpe (8,3 mm de longitud estándar, LE) con la aparición de los primeros procesos neurales, hemales y cuerpos vertebrales pre-caudales. La osificación de la columna vertebral ocurrió en sentido cráneo-caudal y fue completa a los 28 dpe (22,6 mm LE). El esqueleto caudal inició su desarrollo entre los 6 y 8 dpe con la formación de los hipurales (H), parahipural (PH) y los radios caudales principales y secundarios. Los H 1 al 3 se formaron como primordios cartilaginosos en la cara ventral de la porción distal de la notocorda, mientras que posteriormente se formaron los H 4 al 6 y el PH. Los primeros radios de la aleta caudal fueron observados en correspondencia con la formación de los H 2 y 3, mientras que a los 28 dpe se observó la completa formación de los mismos, existiendo 10 radios en el lóbulo dorsal y 9 en el lóbulo ventral. Los epurales, en número de tres, fueron evidentes como elementos cartilaginosos en dorsal de la notocorda y distalmente a los arcos neurales, permaneciendo sin osificarse hasta los 25 dpe. El complejo centro ural se constituyó por la fusión de tres estructuras, el centro preural 1, el ural 1 y 2. El desarrollo de la columna vertebral y del esqueleto caudal muestran patrones similares a los descriptos en otros teleósteos.

Growth, survival and bone alterations in Piaractus mesopotamicus larvae under different rearing protocols / Crescimento, sobrevivência e alterações ósseas em larvas de Piaractus mesopotamicus em diferentes protocolos de criação

The pacu (Piaractus mesopotamicus) is a neotropical freshwater fish. It is one of the most important species farmed in areas of the Parana and Paraguay Rivers basins. The effects of different rearing protocols on growth, survival and incidence of skeletal malformations in pacu larvae were analyzed. A total of six experimental treatments were considered, consisting of: a semi-intensive larviculture (L_S) in ponds; intensive larviculture (L_In) in laboratory (both L_S and L_In until 60 days of life); and mixed larviculture, with 20 days of semi-intensive larviculture into cages in ponds after 14 (L₁), 21 (L₂), 33 (L₃) or 40 (L₄) days of laboratory larviculture. At the end of the experimental period, L_Slarvae showed higher growth rate, with average weight values (2.28g) and total length (TL-48.20mm) statistically higher than the rest (P<0.05). L₁ to L₄ treatments showed intermediate growth values, without differences between them (P>0.05), while L_In presented the lowest growth (P<0.05). Survival was around 75% in all experimental groups, except L_S, that presented a significantly lower value (17.5%, P<0.05). Skeletal abnormalities were detected in all experimental treatments, but L_In and L₁ presented the lowest incidence. In no case, visible morphological alterations were found. This study shows that prolonging pacu rearing under laboratory conditions at high densities improves temporal availability and survival of juvenile without affecting growth or subsequent osteological development of fish.

O pacu (Piaractus mesopotamicus) é um peixe neotropical de água doce. É uma das espécies mais importantes cultivadas em áreas de bacias dos rios Paraná e Paraguay. Foi analisado o efeito da duração da larvicultura intensiva no crescimento, sobrevivência e incidência de malformações ósseas em pacu. Os tratamentos consistiram de uma larvicultura semi-intensiva (L_S) em viveiros, larvicultura intensiva no laboratório até 60 dias de idade (L_In), ou misto, com 20 dias de larvicultura semi-intensiva após 14 (L₁), 21 (L₂), 33 (L₃) e 40 (L₄) dias de larvicultura no laboratório. No final da experiência, as larvas do tratamento L_S apresentaram maior crescimento, com valores de peso médios (2,28g) e comprimento total (CT-48,20mm) estatisticamente superior ao resto (P<0,05). Os tratamentos L₁ a L₄apresentaram valores de crescimento intermediários, sem diferença estatística entre eles (P>0,05), enquanto L_In apresentaram os menores valores de crescimento estimados (P<0,05). A sobrevivência foi estimada em torno de 75% em todos os grupos, com exceção do L_S, o qual apresentou um valor mais baixo (17,5%, P<0,05). Em todos os tratamentos experimentais, foram detectadas alterações esqueléticas, mas em nenhum caso foi encontrado alteração morfológica visível. O presente estudo mostra que a retenção prolongada de larvas de pacu em alta densidade melhora a disponibilidade temporal e sobrevivência dos juvenis, sem afetar o crescimento ou desenvolvimento osteológico posterior destes.

Desarrollo Ontogénico de la Columna Vertebral y del Esqueleto Caudal en Larvas de Rhamdia quelen en Condiciones de Larvicultura Intensiva / Ontogenic Development of the Vertebral Column and Caudal Skeleton in Rhamdia quelen Larvae in Larviculture Intensive System

Se analiza por primera vez el desarrollo osteológico de la columna vertebral y del esqueleto caudal en larvas de Rhamdia quelen mantenidas bajo condiciones controladas y con alimentación artificial. Entre los días 1 a 20 posteriores a la eclosión (dpe) se muestrearon a intervalos regulares 400 larvas, que se colorearon y transparentaron siguiendo la técnica de Taylor & Van Dike. En los primeros días de vida, las larvas presentan una notocorda recta en toda su longitud. El inicio de la formación de la columna vertebral fue observado a los 7 dpe con la aparición de las espinas neurales y hemales, y entre los 9 y 10 dpe para las tres primeras vértebras. La osificación de la columna vertebral ocurrió en sentido cráneo-caudal y fue completa a los 20 dpe. El esqueleto caudal inicia su desarrollo entre los 3 y 4 dpe, con la formación de los hipurales (H), parahipural (PH) y los radios caudales. Los H 1 al 4 se formaron como primordios cartilaginosos en la cara ventral de la porción distal de la notocorda, mientras que posteriormente lo hicieron el H 5 y el PH en el extremo distal y proximal del esqueleto caudal, respectivamente. El complejo centro ural (CCU) se osificó inicialmente en dos partes, una anterior que resulta de la combinación del centro preural 1 y el ural 1 y una posterior con el ural 2. Los primeros radios de la aleta caudal aparecieron en larvas en flexión, mientras que después de los 13 dpe, todos los ejemplares presentaron los radios principales osificados (ocho en la parte superior y ocho en la inferior). El desarrollo de la columna vertebral y del esqueleto caudal en R. quelen muestra patrones similares a los descriptos en otros peces teleósteos aunque con algunas particularidades que lo diferencian de los grupos relacionados.

The osteological development of vertebral column and caudal skeleton in Rhamdia quelen larvae under controlled conditions and artificial feeding is analyzed. Between 1 to 20 day post hatching (dph) four hundred larvae were sampled at regular intervals, and subsequently colored and transparent following the Taylor & Van Dyke technique. In the first days of life, larvae have a straight notochord throughout its length. The beginning of the vertebral column formation was observed at 7 dph with the emergence of neural and haemal spines arches, and between 9 and 10 dph for the first three vertebrae. The ossification of the vertebral column occurred in cranial-caudal direction and was complete at 20 dph. The caudal skeleton begins to develop between 3 and 4 dph, with the formation of the hypurals (H), parahipural (PH) and caudal fin rays. The H 1 to 4 were formed as cartilaginous primordia on the ventral surface of the distal portion of the notochord, and then later the H 5 and PH in distal and proximal extreme of the caudal skeleton, respectively. Central ural complex (CUC) was ossified in two parts, one anterior that is a combination of central preural 1 and ural 1 and other posterior with the ural 2. The first caudal fin rays appear in flexion larvae, while after 13 dph, all specimens had ossified principal rays (eight rays in both upper and lower lobes). The development of the vertebral column and caudal skeleton shows similar patterns to those described in other teleost fish although with some peculiarities that differentiate it from related groups.

Dietary soybean meal on growth and intestinal morphology of South American catfish, Rhamdia quelen, larvae / Farelo de soja em dietas para larvas de jundiá (Rhamdia quelen) sobre o crescimento e morfologia intestinal

The effects of the replacement of bread yeast by soybean meal in diets for Rhamdia quelen larvae on growth, survival, and intestinal morphology were analysed. Larvae were fed for 20 days with five diets: a control diet formulated with 57% of bread yeast, and other four diets in which soybean meal at concentrations of 14.25, 28.5, 42.75 and 57% was added to obtain 25, 50, 75 and 100% of bread yeast replacement. Growth and survival parameters were negatively affected by dietary soybean meal inclusion. Larvae fed control diet showed significantly higher mean weight, specific growth rate, final biomass, and survival rate than larvae from other treatments. Enterocyte height and fold width of the posterior intestine showed highest values in the control group, and an inverse linear relationship with the level of dietary soybean meal inclusion was observed, however, in the anterior intestine the morphology parameters were not affected by the diet. These results indicate that inclusion of soybean meal in diets for R. quelen larvae negatively affects growth and survival, as well as the capacity for digestion and absorption of nutrients, mainly in the posterior intestine.

Neste estudo, foi analisado o efeito da substituição de levedura de pão por farelo de soja em dietas para larvas de Rhamdia quelen no crescimento, sobrevivência e morfologia intestinal. As larvas foram alimentadas durante 20 dias com cinco dietas experimentais: uma dieta controle formulada com 57% de levedura de pão e quatro dietas em que o farelo de soja foi adicionado em 14,25, 28,5, 42,75 e 57% para obter 25, 50, 75 e 100% de substituição de levedura de pão. As variáveis de crescimento e sobrevivência foram negativamente afetadas pela inclusão da soja na dieta. As larvas alimentadas com a dieta controle apresentaram maior peso médio, taxa de crescimento específico, biomassa final e sobrevivência, diferindo significativamente dos demais tratamentos. A altura dos enterócitos e a largura das pregas no intestino posterior apresentaram valores mais elevados no grupo controle, enquanto nos demais tratamentos mostraram uma relação linear inversa com o nível de inclusão de farelo de soja na dieta. No entanto, no intestino anterior, os parâmetros morfológicos não foram afetados pela dieta. Esses resultados indicam que a inclusão de farelo de soja em dietas para larvas de R. quelen afeta negativamente o crescimento e sobrevivência, bem como a capacidade de digestão e absorção de nutrientes, principalmente no intestino posterior.

Duração da larvicultura sobre o desempenho posterior de juvenis de jundiá, Rhamdia quelen, recriados em tanques-rede / Hatchery duration influence on posterior performance of jundiá fingerlings, Rhamdia quelen, reared in cages

Realizou-se um experimento fatorial 3x2, com três repetições (n=18), a fim de avaliar o crescimento e a sobrevivência de juvenis de jundiá (Rhamdia quelen) recriados em tanques-rede e dispostos em tanques externos até os 65 dias de vida. Os peixes utilizados provêm de um sistema de larvicultura intensiva, em que foram alimentados em laboratório com três rações diferentes até os 10 e 15 dias de vida, antes de serem transferidos para os tanques-rede. Uma vez nos tanques-rede, os peixes foram alimentados até a saciedade com ração balanceada comercial contendo 28 por cento de proteína bruta. Ao final do ensaio, não foram observadas diferenças significativas entre os tratamentos para nenhum dos parâmetros estimados (P>0,05). Da mesma maneira, os valores de crescimento e sobrevivência obtidos foram similares entre os grupos de peixes transferidos aos 10 e 15 dias de vida. Os resultados demonstram que a passagem das larvas de jundiá para os tanques-rede de recria aos 10 dias de vida seria o manejo mais recomendável, diminuindo os custos da alimentação e operativos que implicam o estágio de larvicultura sob condições controladas de laboratório.

A 3x2 factorial trial with three replicates (n=18) was carried out aiming to evaluate Rhamdia quelen fingerling growth and survival rates, stocked in cages, in external ponds until attain 65 days of life. Fish used come from an intensive hatchery system, where were fed in laboratory with three different diets until attain 10 and 15 days old, before being transferred to cages. Once in cages, fishes were fed until satiation with commercial balanced diet containing 28 percent crude protein. At the end of the experience, there were no significant differences between treatments for any of the estimated parameters (P> 0.05). Similarly, the values of growth and survival obtained were similar between the groups of fish transferred with 10 and 15 days old. The results show that transference of 10 days old catfish larvae to the cages would be the more appropriate management, reducing feeding and operating costs that involves the larviculture under controlled laboratory conditions.

Fontes não-convencionais de proteína na primeira alimentação do bagre sul americano (Rhamdia quelen) / Unconventional protein sources in the first feeding of South American catfish (Rhamdia quelen)

O presente estudo teve como objetivo avaliar diferentes fontes de proteína na primeira alimentação de jundiá (Rhamdia quelen) sob condições de laboratório. Foram testadas três rações balanceadas secas: ovo de peixe (TA), hidrolisado de carcaça do peixe (TB) e fígado de frango cru (TC), na quais foram analisadas, pelo crescimento, a biomassa final produzida e a sobrevivência das larvas. O ensaio teve uma duração de 20 dias, e as rações foram fornecidas ad libitum. As larvas alimentadas com ovo de peixe apresentaram os melhores resultados com peso médio individual de 340mg, sobrevivência de 57 por cento e biomassa final de 1.350mg, diferindo significativamente dos demais tratamentos. Os resultados indicaram que a formulação de rações balanceadas com ovos de peixes fornecida na primeira alimentação de larvas de jundiá pode tornar-se uma alternativa promissora na larvicultura dessa espécie.

This study aimed to evaluate different proteins sources in first feeding of jundiá (Rhamdia quelen) under laboratory conditions. Three balanced dry rations were tested, fish roe (TA), biological fish silage (TB) and crude chicken liver (TC) evaluating specific growth rate, final biomass produced and survival rate. The experiment was performed in 20 days, and all the rations were provided ad libitum. Larvae fed with fish roe presented better results, with 340mg of individual mean weight, 57 percent of survival rate and 1.350mg of final biomass, differing significantly with the other treatments. The results show that the inclusion of fish roe in balanced rations offered at the first feeding of jundiá larvae may become a promising alternative for the hatchering of the species.