Effects of Lyophilized Açaí (Euterpe oleracea) Supplementation on Oxidative Damage and Intestinal Histology in Juvenile Shrimp Penaeus vannamei Reared in Biofloc Systems.

The objective of this was to evaluate the ability of bioflocs to assimilate and transfer antioxidant compounds present in açaí Euterpe oleracea to juvenile Penaeus vannamei shrimp grown in a biofloc system. Juvenile shrimp were distributed into four treatment groups (control, 5, 20, and 80 mg açaí L-1), containing 31 shrimps/tank (90 L), and cultivated for 30 days. Every 24 h throughout the experimental period, the respective açaí concentrations were added directly to the cultivation water. The bioflocs and hepatopancreas lost their antioxidant capacity with increasing concentrations of açaí; however, lipid damage was mitigated after treatment with 20 mg of açaí L-1 (p < 0.05). The application of 20 mg açaí L-1 increased the mean height and area of the middle intestinal microvilli (p < 0.05). Mortality and protein and lipid damage in shrimp muscle increased with daily administration of 80 mg açaí L-1 (p < 0.05). It is concluded that the bioflocs were able to assimilate the antioxidants present in açaí and transfer them to the shrimp, and the administration of 20 mg açaí L-1 presented the best performance, demonstrating the possibility of its application in the cultivation of P. vannamei in a biofloc system.

Oxidative effects of consuming microplastics in different tissues of white shrimp Litopenaeus vannamei.

In this study, we evaluated the effect of microplastic (MP, polystyrene, 1.1 µm) exposure through diet at two different levels (40 and 400 µg MP/kg of ration) in the shrimp Litopenaeus vannamei for seven days. After the exposure period, oxidative stress parameters, histological alterations, and MP accumulation in different shrimp tissues (gut, gills, hepatopancreas, and muscle) were also evaluated. The results showed that MP was detected in the gills, muscles, and hepatopancreas. In addition, in the gut, gills, and hepatopancreas, disruption in redox cells was observed. Also, lipid and DNA damage was evident in the hepatopancreas. Histopathological analysis revealed edema in the intestine, hepatopancreas, and in the muscle. Granuloma formation with infiltrated hemocytes occurred in the intestine and hepatopancreas. These results show that MP exposure can affect the health and welfare of L. vannamei and may also affect the final consumers once MP is accumulated.

Silver nano/microparticle toxicity in the shrimp Litopenaeus vannamei (Boone, 1931).

The effects of silver nano/microparticles (AgP) on juvenile Litopenaeus vannamei shrimp were evaluated through several responses, aiming to use it as a prophylactic and therapeutic method. Shrimps (3.19 ± 0.13 g) were exposed to clear water for 3 h with increasing concentrations of nanosilver (0; 25; 100; and 400 µg/l). After 3 h of exposure, they were transferred to water without nanosilver for 30 days (recovery). The weight gain and weekly growth were not affected by AgNP. Total antioxidant capacity (ACAP) increased in the hepatopancreas (exposure period) and gills (recovery) in shrimp exposed to AgNP. In muscle, ACAP was induced in shrimp exposed to 100 µg/l AgNP (exposure). In the gills, there was an increase in TBARS in shrimp exposed to 100 µg/l AgNP (recovery). In the concentration of protein-associated sulfhydryl groups (P-SH), a decrease was observed in the hepatopancreas (recovery) in the 100 µg/l AgNP treatment. In chromaticity parameters, an increase in reddish tones was observed in shrimp exposed to 100 µg/l AgNP (recovery). An increase in granular hemocytes was verified in shrimp exposed to 25 and 400 µg/l AgNP during exposure. Tissues analyzed histologically showed normal patterns without apoptosis or necrosis processes, and after 30 d of recovery, only in one muscle sample of shrimp exposed to µg/l of AgNP was silver detected. It is concluded that a prophylactic action of short duration (3 h) mostly did not affected the welfare of shrimp L. vannamei and can be considered its use as a therapeutic strategy.

Growth Hormone Overexpression Induces Hyperphagia and Intestinal Morphophysiological Adaptations to Improve Nutrient Uptake in Zebrafish.

The excess of circulating growth hormone (GH) in most transgenic animals implies mandatory growth resulting in higher metabolic demand. Considering that the intestine is the main organ responsible for the digestion, absorption, and direction of dietary nutrients to other tissues, this study aimed to investigate the mechanisms by which gh overexpression modulates the intestine to support higher growth. For this purpose, we designed an 8-weeks feeding trial to evaluate growth parameters, feed intake, and intestinal morphometric indices in the adult gh-transgenic zebrafish (Danio rerio) model. To access the sensitivity of the intestine to the excess of circulating GH, the messenger RNA (mRNA) expression of intestine GH receptors (GHRs) (ghra and ghrb) was analyzed. In addition, the expression of insulin-like growth factor 1a (igf1a) and genes encoding for di and tripeptide transporters (pept1a and pept1b) were assessed. Gh-transgenic zebrafish had better growth performance and higher feed intake compared to non-transgenic sibling controls. Chronic excess of GH upregulates the expression of its cognate receptor (ghrb) and the main growth factor related to trophic effects in the intestine (igf1a). Moreover, transgenic zebrafish showed an increased intestinal absorptive area and higher expression of crucial genes related to the absorption of products from meal protein degradation. These results reinforce the ability of GH to modulate intestinal morphology and the mechanisms of assimilation of nutrients to sustain the energy demand for the continuous growth induced by the excess of circulating GH.

Mast cells and eosinophilic granule cells in Oncorhynchus mykiss: Are they similar or different?

Mast cells are important in inflammatory processes and in the nonspecific immune response, and there are also indications that these cells are associated with the effectors of the specific immune response. Eosinophilic granular cells are frequently compared to mast cells, and some authors maintain that they are the same cells. In this study, we take a fresh look at the similarities and differences between these two cell types in Oncorhynchus mykiss. We evaluated the cytomorphology of each cell type with optical microscopy, their staining affinities, and their ultrastructure. We observed that mast cells were positive for CD117 (c-kit), while eosinophilic granular cells were negative for this marker. We propose that these two cell types have certain common characteristics but represent well-differentiated populations distributed in several Oncorhynchus mykiss tissues.

Ultrastructural study of the thymus of Mugil liza Valenciennes, 1836 juveniles.

•Mugil liza is a species with potential production in aquaculture.•It is a spice that suffers from various diseases.•Knowing your immune system is important for this activity.•Electron microscopy unlike optical microscopy allows to study in detail the different types of cells that compose it.•Electron microscopy allows evaluating thymus histiogenesis .

Effect of salinity on embryo-larval development of yellow clam Mesodesma mactroides (Reeve, 1854) in laboratory.

Abstract: This study assessed the effect of salinity on embryonic development, larval growth and survival of the yellow clam Mesodesma mactroides in laboratory. Embryos and larvae of M. mactroides were submitted and maintained at four different salinities: 20, 25, 30 and 35 ppt, to determine optimal conditions for the species. Through descriptive analysis, the results showed that the embryos tolerate salinities between 25 - 35 ppt, presenting fast metamorphoses at salinities 30 and 35 ppt, during experimental period of 27 hours. The same tolerance pattern was observed in larval stage (25 - 35 ppt), showing a better development in salinity of 35 ppt. This result is verified in biometric analyzes of height and length of the shells and survival rate, with higher averages in treatments with salinity 35 ppt. The experimental period of this stage lasted 27 days, when the larvae were able to settle. These results indicate that embryos and larvae of M. mactroides tolerate salinities between (25-35 ppt), with the best growth and survival on high salinities being recommended to better yields in laboratory.

Embryo and larval development of the yellow clam Mesodesma mactroides (Reeve, 1854) (Mesodesmatidae) in laboratory.

The yellow clam Mesodesma mactroides (Reeve, 1854) is a sand mollusc with historical and socioeconomic importance in Brazil, Uruguay and Argentina. A guaranteed form to access a successful reestablishment of the species in their natural environment is directly linked to their reproduction biology. Then, our report introduces the embryonic and larval development of the yellow clam reared in laboratory for such purposes. M. mactroides broodstock were selected as specimens who possess a mean total shell length and weight of 66 ± 3.82 mm and 27.15 ± 4.07 g for an afterwards spawn induction through stripping technique. Regarding the embryonic development, newly fertilized oocytes exhibited a mean diameter of 51.20 ± 6.64 µm. The first polar corpuscle, trochophores and D-veliger appeared at 20 min, 18 and 24 h after fertilization, respectively. Umbonate and pediveliger larvae were noticed on the 8th and 25th day, respectively, with complete metamorphosis occurring only at the 27th day, when all larvae were retained in a 200 µm nylon mesh. Therefore, with that basic understanding of the embryonic and larval development of M. mactroides in the laboratory, forwards studies will focus in establish a technological package for this species.

Fishmeal substitution for Arthrospira platensis in juvenile mullet ( Mugil liza) and its effects on growth and non-specific immune parameters / Substitución de harina de pescado por Arthrospira platensis en juveniles de lisa (Mugil liza) y sus efectos en el crecimiento y parámetros del sistema inmune no-específico / Substituição da farinha de peixe por Arthrospira platensis em juvenis de tainha (Mugil liza) e seus efeitos no crescimento e nos parâmetros do sistema imune não-especifico

Abstract Background: Cyanobacterium Athrospira platensis (Spirulina) is a potential fishmeal (FM) substitute in fish diets because of its high protein content, antioxidant and immunostimulant properties. Objective: To evaluate the effects of total and partial substitution of FM with A. platensis (0, 30, 50, 70 and 100% substitution) in juvenile mullet (Mugil liza). Methods: Juvenile mullets (n=210) were maintained in a recirculation system under optimal water parameters for the species. Mullets were fed five experimental diets for 80 days. Each diet was tested in triplicate tanks. At the end of the experimental period growth parameters were measured and samples of blood, liver and spleen were taken to evaluate the immune system. Results: Full replacement (100%) of FM resulted in growth deficits and low survival. The FM replacement induced changes in the proportion of macrophages and lymphocytes. Up to 50% FM replacement increased the expression of CD3 receptors in spleen T lymphocytes (T-Cells), whereas >50% FM replacement decreased the expression of CD3 receptors. We also found that partial FM substitution diminished the apoptotic process. Conclusions: Up to 50% FM substitution with A. platensis can improve performance of non-specific immune system of mullets.

Resumen Antecedentes: La cianobacteria Arthrospira platensis (Spirulina) puede usarse como substituto potencial de la harina de pescado (HP) por su alto contenido de proteína, sus antioxidantes y sus propiedades inmunoestimulantes. Objetivo: Analizar el efecto de la substitución parcial y total de HP por A. platensis (0, 30, 50, 70 y 100% de substitución) en juveniles de lisa (Mugil liza). Métodos: Juveniles de lisa (n=210) se mantuvieron en un sistema de recirculación con parámetros de calidad de agua en niveles óptimos para la especie. Las lisas se alimentaron con las dietas experimentales durante 80 días. Cada dieta fue evaluada en triplicado. Al final del periodo experimental se midieron los parámetros de crecimiento y se colectaron muestras de sangre, hígado y bazo para evaluación del sistema inmune. Resultados: La substitución total (100%) resultó en deficiente crecimiento y baja sobrevivencia. El remplazo de HP produjo cambios en las proporciones de macrófagos y linfocitos. La substitución de hasta un 50% HP aumentó la expresión de receptores CD3 en linfocitos T del bazo. Por otro lado, la substitución mayor a 50% HP disminuyó la expresión de receptores CD3. La substitución parcial de HP disminuyó el proceso de apoptosis. Conclusiones: Proponemos una substitución de HP del 50% por A. platensis, lo cual mejora el desempeño del sistema inmune no especifico de las lisas.

Resumo Antecedentes: A cianobactéria Athrospira platensis (Spirulina) é um potencial substituto da farinha de peixe (FP) pelo seu alto conteúdo de proteína, antioxidantes e características imune estimulantes. Objetivo: Foram avaliados os efeitos da substituição parcial e total da FP por A. platensis (0, 30, 50, 70 e 100% substituição) em juvenis de tainha (Mugil liza). Métodos: Juvenis de tainha (n=210) foram mantidos em um sistema de recirculação com os parâmetros da água sendo mantidos em níveis ótimos para a espécie. As tainhas foram alimentadas com as dietas experimentais por 80 dias, cada dieta foi testada em triplicata, ao final do período experimental foram avaliados os parâmetros de crescimento e amostras de sangue, fígado e baço foram coletadas para a avaliação do sistema imune. Resultados: A substituição total de FP resultou em redução do crescimento e baixa sobrevivência. A avaliação do sistema imune demostrou que a substituição da FP produz alterações nas proporções de macrófagos e linfócitos. Provou-se que até 50% de substituição da FP incrementa a expressão de receptores CD3. Além disso, a substituição parcial da FP diminui o processo de apoptose. Conclusão: Baseado em nossos descobrimentos, se propõe a substituição de até 50% da FP por A. platensis que melhorará o desempenho do sistema imunológico não específico das tainhas.

Histological evaluation of vital organs of the livebearer Jenynsia multidentata (Jenyns, 1842) exposed to glyphosate: A comparative analysis of Roundup® formulations.

Roundup formulations are herbicides whose active principle is glyphosate. However, these formulations are potentially more toxic to non-target organisms than pure glyphosate. This study aimed to evaluate and compare the toxic potential of the Roundup formulations through histological alterations in fish. Thus, males and females of the neotropical fish species Jenynsia multidentata (Jenyns, 1842) were exposed for 24 or 96 h to the Roundup Original® (RO), Roundup Transorb® (RT) or Roundup WG® (RWG) formulations, at a fixed concentration of 0.5 mg/L of glyphosate. This concentration is close to the maximum glyphosate limits found in the environment and is non-lethal to J. multidentata. The three formulations caused histological damage to the liver, gills and brain of J. multidentata, which increased over the exposure time. Differences in the histological alterations between females and males were observed in the liver and brain. Females were more tolerant to RO and RT than RWG. Males did not exhibit these differences in sensitiveness with formulations. The RWG caused more damage in the liver and gills and RT in the brain. Overall, there were differences in the toxicity of RO, RT and RWG and the toxic effect was presented through histological damage, reinforcing the usefulness of histological biomarkers for Roundup® toxicity. The comparison of the toxic potential of glyphosate-based herbicides is important because it could give support to the governmental organizations to set protective rules for the water ecosystems and human health, as well as to reduce the use of highly toxic formulations in agriculture.

Fish oil and meal replacement in mullet (Mugil liza) diet with Spirulina (Arthrospira platensis) and linseed oil.

This research evaluated the effect of the simultaneous substitution of fish meal and fish oil at 0, 30, 50, 70 and 100% (termed SS0, SS30, SS50, SS70 and SS100, respectively) with both Spirulina (Arthrospira platensis) and linseed oil. The effect on growth, colour, fatty acid (FA) profile, and liver and muscle antioxidant response in mullets (Mugil liza) were evaluated. A full substitution was not possible due to a final body weight reduction (p < 0.05). The colorimetric analyses showed an improvement in fillet colouration (p < 0.05). Also, we found a saturation of carotenoids in muscle at 30% substitution. The content of highly unsaturated fatty acids - HUFA (DHA, EPA and ARA) in muscle diminished as the substitution level increased and, at the same time, the level of these FAs in the diet diminished. We found interesting evidence of elongation from 18:3n-3 to 20:3n-3 when substitution with linseed oil levels was above 50% but no desaturation to 20:4 or 20:5n-3 was found, which could insinuate a certain n-3 HUFA requirement under the experimental conditions. Moreover, we noted an increase in the antioxidant capacity up to the treatment SS70; the SS100 treatment showed a diminution in the antioxidant capacity. It is concluded that a partial inclusion of Spirulina and linseed oil (50%) is possible, and that this replacement can increase antioxidant responses, improve its growth performance and can modulate the mullets fillet quality without affecting negatively fillet fatty acid content.

Use of exogenous enzymes in diets for juvenile pompano Trachinotus marginatus: growth and liver and intestine morphophysiology / Uso de enzimas exógenas em dietas para juvenis de pampo Trachinotus marginatus: crescimento e morfofiologia do fígado e intestino

This study investigated the use of exogenous enzymes in diets of juvenile pompano Trachinotus marginatus. Six diets (43% protein, 8% lipid), containing 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250), and 500 (T500) mg kg-1 of multiple enzymes Rovabio® MAX AP were produced. The effects on growth performance, body composition, liver glycogen, triglyceride levels, and intestinal and hepatic morphological alterations were assessed. The results showed significant differences (p < 0.05) in growth performance among fish fed diets T100, T250, and T500, with high liver triglyceride accumulation and changes in morphology in the fish fed diets T250 and T500. The calcium concentration in the bones showed a significant difference (P < 0.05) only in fish fed diets T50, T100, and T250 in relation to control. However, there were no significant differences in body composition, intestinal morphology, or liver glycogen concentration. These results suggest that 100 mg enzyme per kg diet was the optimal level of inclusion for juvenile pompano, favoring improved growth performance and calcium concentration in the bones without significant effects on liver triglyceride levels.

Este estudo investigou o uso de enzimas exógenas em dietas para juvenis de pampo prateado Trachinotus marginatus. Foram preparadas seis dietas (43% de proteína, 8% de lipídio), contendo 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250) e 500 (T500) mg kg-1 do complexo enzimático Rovabio® Max AP. Avaliou-se os efeitos sobre o crescimento, composição de carcaça, níveis de glicogênio e triglicerídeo no fígado e possíveis alterações na morfologia do intestino e fígado. Os resultados mostraram diferença significativa (p 0,05) na composição de carcaça, morfologia do intestino e concentração de glicogênio no fígado. Esses resultados indicam que o uso de 100 mg kg-1 de enzimas na dieta mostrou ser o melhor nível de inclusão para juvenis de pampo prateado, favorecendo o crescimento e a concentração de cálcio nos ossos. Sem efeitos significativos sobre os níveis de triglicerídeos no fígado.

Use of exogenous enzymes in diets for juvenile pompano Trachinotus marginatus: growth and liver and intestine morphophysiology / Uso de enzimas exógenas em dietas para juvenis de pampo Trachinotus marginatus: crescimento e morfofiologia do fígado e intestino

This study investigated the use of exogenous enzymes in diets of juvenile pompano Trachinotus marginatus. Six diets (43% protein, 8% lipid), containing 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250), and 500 (T500) mg kg-1 of multiple enzymes Rovabio® MAX AP were produced. The effects on growth performance, body composition, liver glycogen, triglyceride levels, and intestinal and hepatic morphological alterations were assessed. The results showed significant differences (p < 0.05) in growth performance among fish fed diets T100, T250, and T500, with high liver triglyceride accumulation and changes in morphology in the fish fed diets T250 and T500. The calcium concentration in the bones showed a significant difference (P < 0.05) only in fish fed diets T50, T100, and T250 in relation to control. However, there were no significant differences in body composition, intestinal morphology, or liver glycogen concentration. These results suggest that 100 mg enzyme per kg diet was the optimal level of inclusion for juvenile pompano, favoring improved growth performance and calcium concentration in the bones without significant effects on liver triglyceride levels.(AU)

Este estudo investigou o uso de enzimas exógenas em dietas para juvenis de pampo prateado Trachinotus marginatus. Foram preparadas seis dietas (43% de proteína, 8% de lipídio), contendo 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250) e 500 (T500) mg kg-1 do complexo enzimático Rovabio® Max AP. Avaliou-se os efeitos sobre o crescimento, composição de carcaça, níveis de glicogênio e triglicerídeo no fígado e possíveis alterações na morfologia do intestino e fígado. Os resultados mostraram diferença significativa (p < 0,05) no desempenho de crescimento dos peixes dos tratamentos T100, T250 e T500, com grande concentração de triglicerídeos e alteração na morfologia do fígado nos peixes dos tratamentos T250 e T500. A concentração de cálcio nos ossos também teve um aumento significativo (p < 0,05) nos peixes dos tratamentos T50, T100 e T250 em relação ao controle. Entretanto, não houve diferença significativa (p > 0,05) na composição de carcaça, morfologia do intestino e concentração de glicogênio no fígado. Esses resultados indicam que o uso de 100 mg kg-1 de enzimas na dieta mostrou ser o melhor nível de inclusão para juvenis de pampo prateado, favorecendo o crescimento e a concentração de cálcio nos ossos. Sem efeitos significativos sobre os níveis de triglicerídeos no fígado.(AU)

Different crystalline forms of titanium dioxide nanomaterial (rutile and anatase) can influence the toxicity of copper in golden mussel Limnoperna fortunei?

Although some studies have showed the effects of different crystalline structures of nTiO2 (anatase and rutile) and their applicability in several fields, few studies has analyzed the effect of coexposure with other environmental contaminants such as copper. Thus, the objective of this study was to evaluate if the coexposure to nTiO2 (nominal concentration of 1 mg/L; anatase or rutile) can increase the incorporation and toxic effect induced by Cu (nominal concentration of 56 µg/L) in different tissues of Linmoperna fortunei after 120 h of exposure. Our results showed that the coexposure increased the accumulation of Cu in the gills and adductor muscle independently of the crystalline form and can positively or negatively modulate the antioxidant system, depending on the tissue analyzed. However, exposure only to rutile nTiO2 induced damage in the adductor muscle evidenced by the infiltration of hemocytes in this tissue. Additionally, histomorphometric changes based on fractal dimension analysis showed that coexposure to both forms of nTiO2 induced damage in the same tissue. These results suggest that both crystalline forms exhibited toxicity depending on the analyzed tissue and that coexposure of nTiO2 with Cu may be harmful in L. fortunei, indicating that increased attention to the use and release of nTiO2 in the environment is needed to avoid deleterious effects in aquatic biota.

Metaplasia in swim bladder epithelium of the endangered annual fish Austrolebias nigrofasciatus (Cyprinodontiformes: Rivulidae) results in inadequate swimming and delayed growth

Laboratory breeding of annual fish is often impaired when fish fail to inflate the swim bladder after hatching. These fish, which are known as belly-sliders, cannot swim in the water column, moving mainly on the bottom of water. Therefore, we wanted to understand the factors underlying failed inflation of swim bladder in the annual fish Austrolebias nigrofasciatus and determine the implications of this condition on the growth of juveniles. To identify how the initial filling of the gaseous vesicle is compromised, and to determine the implications of this condition on juvenile growth, we analysed the histology of the swim bladder of both normal swimming fish and belly-sliders during their initial growth phase (first month of life). In addition to slower growth rate compared with fish swimming normally, we found that belly-sliders have metaplasia characterized by epithelium peeling of the swim bladder and the presence of haemorrhage. Based on our findings, it can be concluded that metaplasia of the swim bladder is recurrent in annual fish bred in the laboratory, which explains the large number of unviable larvae. However, its causes remain unknown.(AU)

A criação de peixes anuais é frequentemente comprometida pela ocorrência de peixes que não inflam a vesícula gasosa após a eclosão. Estes peixes não têm capacidade de se manter e nadar na coluna d'água e se locomovem no fundo da água, por isso são chamados belly-sliders. Portanto, objetivamos entender os fatores subjacentes à inflação falhada da bexiga natatória no peixe anual Austrolebias nigrofasciatus e determinar as implicações dessa condição no crescimento de juvenis. Para identificar de que forma o enchimento inicial da vesícula gasosa é comprometido, e determinar as implicações desta condição no crescimento dos juvenis, analisamos histologicamente a vesícula gasosa de peixes com natação normal e de belly-sliders durante o crescimento inicial (primeiro mês de vida). Verificamos que os belly-sliders apresentam metaplasia com descamação do epitélio da vesícula gasosa e presença de hemorragia, além de apresentar crescimento mais lento em relação aos peixes com natação normal. Concluímos que a incidência desta patologia é um problema recorrente e de grande relevância para a manutenção de peixes anuais em laboratório, sendo responsável por uma grande quantidade de juvenis inviáveis, no entanto suas causas permanecem desconhecidas.(AU)

Metaplasia in swim bladder epithelium of the endangered annual fish Austrolebias nigrofasciatus (Cyprinodontiformes: Rivulidae) results in inadequate swimming and delayed growth

Laboratory breeding of annual fish is often impaired when fish fail to inflate the swim bladder after hatching. These fish, which are known as belly-sliders, cannot swim in the water column, moving mainly on the bottom of water. Therefore, we wanted to understand the factors underlying failed inflation of swim bladder in the annual fish Austrolebias nigrofasciatus and determine the implications of this condition on the growth of juveniles. To identify how the initial filling of the gaseous vesicle is compromised, and to determine the implications of this condition on juvenile growth, we analysed the histology of the swim bladder of both normal swimming fish and belly-sliders during their initial growth phase (first month of life). In addition to slower growth rate compared with fish swimming normally, we found that belly-sliders have metaplasia characterized by epithelium peeling of the swim bladder and the presence of haemorrhage. Based on our findings, it can be concluded that metaplasia of the swim bladder is recurrent in annual fish bred in the laboratory, which explains the large number of unviable larvae. However, its causes remain unknown.(AU)

A criação de peixes anuais é frequentemente comprometida pela ocorrência de peixes que não inflam a vesícula gasosa após a eclosão. Estes peixes não têm capacidade de se manter e nadar na coluna d'água e se locomovem no fundo da água, por isso são chamados belly-sliders. Portanto, objetivamos entender os fatores subjacentes à inflação falhada da bexiga natatória no peixe anual Austrolebias nigrofasciatus e determinar as implicações dessa condição no crescimento de juvenis. Para identificar de que forma o enchimento inicial da vesícula gasosa é comprometido, e determinar as implicações desta condição no crescimento dos juvenis, analisamos histologicamente a vesícula gasosa de peixes com natação normal e de belly-sliders durante o crescimento inicial (primeiro mês de vida). Verificamos que os belly-sliders apresentam metaplasia com descamação do epitélio da vesícula gasosa e presença de hemorragia, além de apresentar crescimento mais lento em relação aos peixes com natação normal. Concluímos que a incidência desta patologia é um problema recorrente e de grande relevância para a manutenção de peixes anuais em laboratório, sendo responsável por uma grande quantidade de juvenis inviáveis, no entanto suas causas permanecem desconhecidas.(AU)

Arthrospira platensis filtrada como alimento complementario de juveniles del camarón blanco: efectos sobre crecimiento y sistema inmune / Filtered Arthrospira platensis as a food suplement for juvenile shrimp Litopenaeus vannamei: effects on growth and immune system

De forma general, las microalgas son fuente de alimento indispensable durante las primeras fases de desarrollo de los camarones marinos. Algunas microalgas, como la Arthrospira platensis, son ricas en substancias antioxidantes, y tienen la capacidad de retirar compuestos tóxicos del agua en los sistemas de producción acuícola. De este modo, constituimos un experimento con dos tratamientos triplicados, donde se evaluó la aplicación de biomasa filtrada de microalga A. platensis como suplemento alimenticio para camarón blanco del Pacífico, Litopenaeus vannamei. Se utilizó un sistema de cultivo estático de seis unidades, con volumen útil de 250 litros de agua marina (30 ppt), donde se sembraron 300 camarones m-2 con peso inicial de 0,7±0,2 g. Al final del experimento (42 días) se evaluaron parámetros inmunológicos y de desempeño zootécnico. Los camarones alimentados con A. platensis como como suplemento fueron signicativamente mayores que los camarones del tratamiento control y no presentaron diferencias en la supervivencia. Igualmente, se obtuvieron mejores resultados en los parámetros inmunológicos del tratamiento con inclusión de microalga. De esta forma, al suministrar la microalga como alimento suplementario al camarón L. vannamei, crecimiento y sistema inmunológico se vieron favorecidos.

Microalgae is an important food source during the early stages of marine shrimps. Some microalgae such as Arthrospira platensis, are rich in antioxidant substances and also have the capacity to remove toxics compounds from the water in aquaculture systems. The trial consisted in two treatements by triplicate, where the inclusion of filtered microalgae A. platensis as feed supplementation during production of juvenile Litopenaeus vannamei, was assessed. The experimental desing was based on a static system with six 250-L tanks with marine wáter (30 PSU), stocked 105 shirmps (300 shrimp m-2) with an average wheight of 0,7 ±0,2 g. At the end of the fed trial (42 days), the zootechnical and immunological parameters of shrimps were evaluated. Significatives differences among the treatments were found for both parameters. Shrimps that received supplementation of microalgae A. platensis showed higher growth and better response of the immune system. Thus, these results allow to conclude that the supplementation of filtered microalgae A. platensis improve growth and immunological parameters of white shrimp L. vannamei.

Arthrospira platensis filtrada como alimento complementario de juveniles del camarón blanco: efectos sobre crecimiento y sistema inmune / Filtered Arthrospira platensis as a food suplement for juvenile shrimp Litopenaeus vannamei: effects on growth and immune system

De forma general, las microalgas son fuente de alimento indispensable durante las primeras fases de desarrollo de los camarones marinos. Algunas microalgas, como la Arthrospira platensis, son ricas en substancias antioxidantes, y tienen la capacidad de retirar compuestos tóxicos del agua en los sistemas de producción acuícola. De este modo, constituimos un experimento con dos tratamientos triplicados, donde se evaluó la aplicación de biomasa filtrada de microalga A. platensis como suplemento alimenticio para camarón blanco del Pacífico, Litopenaeus vannamei. Se utilizó un sistema de cultivo estático de seis unidades, con volumen útil de 250 litros de agua marina (30 ppt), donde se sembraron 300 camarones m-2 con peso inicial de 0,7±0,2 g. Al final del experimento (42 días) se evaluaron parámetros inmunológicos y de desempeño zootécnico. Los camarones alimentados con A. platensis como como suplemento fueron signicativamente mayores que los camarones del tratamiento control y no presentaron diferencias en la supervivencia. Igualmente, se obtuvieron mejores resultados en los parámetros inmunológicos del tratamiento con inclusión de microalga. De esta forma, al suministrar la microalga como alimento suplementario al camarón L. vannamei, crecimiento y sistema inmunológico se vieron favorecidos.(AU)

Microalgae is an important food source during the early stages of marine shrimps. Some microalgae such as Arthrospira platensis, are rich in antioxidant substances and also have the capacity to remove toxics compounds from the water in aquaculture systems. The trial consisted in two treatements by triplicate, where the inclusion of filtered microalgae A. platensis as feed supplementation during production of juvenile Litopenaeus vannamei, was assessed. The experimental desing was based on a static system with six 250-L tanks with marine wáter (30 PSU), stocked 105 shirmps (300 shrimp m-2) with an average wheight of 0,7 ±0,2 g. At the end of the fed trial (42 days), the zootechnical and immunological parameters of shrimps were evaluated. Significatives differences among the treatments were found for both parameters. Shrimps that received supplementation of microalgae A. platensis showed higher growth and better response of the immune system. Thus, these results allow to conclude that the supplementation of filtered microalgae A. platensis improve growth and immunological parameters of white shrimp L. vannamei.(AU)

Ammonia exposure and subsequent recovery trigger oxidative stress responses in juveniles of Brazilian flounder Paralichthys orbignyanus.

The effects of ammonia exposure and recovery on oxidative stress parameters and histology of juvenile Brazilian flounder Paralichthys orbignyanus were evaluated. The fish were exposed to 0.12, 0.28 and 0.57 mg NH3-N L-1, plus a control, for 10 days followed by the same recovery time in ammonia-free water. Gill, liver and muscle samples (n = 9) were collected after 1, 5 and 10 days of exposure and after recovery for oxidative stress analysis (antioxidant capacity against peroxyl radicals (ACAP); glutathione S-transferase (GST) activity; lipoperoxidation levels measured through thiobarbituric acid reactive substances (TBARS) content). For histological assessment, gill, liver and brain samples were collected. Exposure to all NH3-N concentrations induced different time- and dose-dependent changes in oxidative stress parameters. Reduced antioxidant capacity of the liver and muscle and enhanced TBARS levels in the gills and liver were demonstrated. Differently, a high ammonia concentration elicited lower hepatic TBARS levels. Enhanced GST activity in all organs and increased antioxidant capacity of the gills were also observed. No ammonia-induced histopathological effects were demonstrated. After recovery, most parameters (liver ACAP, GST activity in the muscle and liver and TBARS in the gills) returned to baseline levels. However, liver TBARS and gill GST activity remained altered 0.57 mg NH3-N L-1 treatment. The recovery period also led to a decrease in gill antioxidant capacity and an increase in muscle antioxidant capacity. In conclusion, a concentration of 0.12 mg NH3-N L-1 induces oxidative stress and antioxidant responses in juvenile Brazilian flounder. Moreover, a 10-day recovery period is not sufficient to restore fish homeostasis.