RESUMO Saguinus bicolor é uma espécie de primata brasileiro, a qual se encontra criticamente em perigo de extinção. Os primatas são comumente parasitados por nematódeos filarídeos, transmitidos por insetos hematófagos, que parasitam vários tecidos e cavidades fora do trato gastrointestinal do hospedeiro. Portanto, o impacto dos helmintos parasitos em seus hospedeiros é um aspecto que não deve ser negligenciado como parte vital da conservação das espécies primatas. Com o presente estudo, objetivou-se descrever, pela primeira vez, o parasitismo por Dipetalonema graciliformis (Filarioidea: Onchocercidae) em Saguinus bicolor (Spix, 1823) no Brasil. Foram fornecidos dados morfológicos detalhados de espécimes fêmeas e, assim, expande-se o número de hospedeiros conhecidos parasitados por essa espécie de filarídeo no país. brasileiro extinção filarídeos hematófagos hospedeiro Portanto estudo objetivouse objetivou descrever vez Filarioidea (Filarioidea Onchocercidae Spix, Spix (Spix 1823 Brasil assim expandese expande país 182 18 1

Patients undergoing chemotherapy with cisplatin commonly present gastrointestinal effects such as constipation and gastric emptying (GE) delay. Both the purinergic system and physical exercise modulate the gastrointestinal (GI) tract. In the current study, we investigated the role of ATP, physical exercise, and P2X7 receptor blocking on GE delay induced by cisplatin in rats. Male rats were divided into the following groups: control (C), cisplatin (Cis), exercise (Ex), Brilliant Blue G (BBG), ATP, Cis+Ex, Cis+ATP, Cis+BBG, Cis+Ex+BBG, Cis+Ex+BBG+ATP, and Cis+ATP+BBG. GE delay was induced by treatment with 1 mg/kg cisplatin (1 time/week for 5 weeks, ip). The moderate physical exercise was swimming (1 h/day, 5 days/week for 5 weeks). At the end of the treatment or exercise and 30 min before the GE assessment, some groups received BBG (50 mg/kg, sc) or ATP (2 mg/kg, sc). Then, GE was assessed after a 10-min postprandial period. Chronic use of Cis decreased GE delay (P<0.05) compared to the control group. Both exercise and ATP prevented (P<0.05) GE delay compared to Cis. The pretreatment with BBG significantly inhibited (P<0.05) the effect of exercise and ATP. On the other hand, the association between exercise and ATP reversed (P<0.05) the effect of the BBG and prevented GE delay. Therefore, we suggest that both exercise and treatment with ATP activate P2X7 receptors and prevent GE delay induced by cisplatin in rats. (GE GI (GI tract study PX P X P2X C, C , (C) Cis, (Cis) Ex, Ex (Ex) BBG, (BBG) CisEx Cis+Ex CisATP Cis+ATP CisBBG Cis+BBG CisExBBG Cis+Ex+BBG CisExBBGATP Cis+Ex+BBG+ATP CisATPBBG Cis+ATP+BBG mgkg mg kg ( timeweek time week weeks ip. ip . ip) hday h day h/day daysweek days weeks. weeks) 3 assessment 50 (5 sc 2 sc. Then 10min 10 period P<0.05 P005 0 05 (P<0.05 group hand Therefore (C (Cis (Ex (BBG P<0.0 P00 (P<0.0 P<0. P0 (P<0. P<0 (P<0 P< (P< (P

COVID-19, caused by SARS-CoV-2, presents diverse symptoms, including neurological manifestations. This study investigated COVID-19's neurological sequelae, focusing on the central nervous system's involvement through cerebral glycolytic metabolism assessed via PET/CT. Twenty-two patients with mild long COVID cognitive symptoms and 20 healthy volunteers without cognitive, psychiatric, or neurological impairments and no history of COVID-19 infection underwent cerebral PET/CT scans using [18F]FDG to assess cerebral metabolism. The study meticulously evaluated the uptake of [18F]FDG in various brain regions, employing the CortexID Suite software for quantitative analysis. The analysis focused on identifying areas of hypometabolism and hypermetabolism, indicative of altered glucose metabolism possibly related to COVID-19's neurological impact. No statistically significant differences were found between the mild COVID and healthy groups. Although our sample was too small to generate a statistical difference between groups, future studies should explore some findings, such as hypometabolism in 15 regions and hypermetabolism in 11 regions in the mild COVID group. These changes, especially in areas linked to executive functions, sensory perception, and emotional regulation, suggest nuanced alterations in brain function. Our study did not find significant glycolytic metabolic changes in patients with mild long COVID. However, areas of glycolytic hypometabolism and hypermetabolism found in some patients showed biological plausibility with the cognitive and affective symptoms they presented. Future investigations with a larger sample size should be correlated with neuropsychological and neuropsychiatric examinations to confirm this relationship. COVID19, COVID19 19, 19 SARSCoV2, SARSCoV2 SARSCoV SARS CoV 2, 2 SARS-CoV-2 manifestations COVID19s COVIDs s sequelae systems system PETCT PET CT Twentytwo Twenty two psychiatric COVID-1 18FFDG FFDG 18F FDG F impact groups findings 1 group functions perception regulation function However presented relationship COVID1 SARS-CoV- COVID- SARS-CoV

Hydrogen permeation tests and tensile mechanical tests were performed at room temperature on API 5CT P110 steel to characterize hydrogen trapping and to evaluate their hydrogen embrittlement susceptibility. The hydrogen trap density was calculated from two consecutive hydrogen permeation transients plotted using an electrochemical cell. Slow strain rate tensile tests on hydrogen-charged samples through cathodic polarization at different potentials were performed to evaluate the hydrogen embrittlement susceptibility. Thereby it was established the lowest potential that characterizes the onset of the cathodic overprotection for studied steel. After mechanical tests was observed a decrease in ductility as the protection potential became more negative and that the fracture mode was changed from ductile microvoid coalescence on the as-received steel to extended quasi-cleavage on the hydrogen-charged steel. The results showed that API 5CT P110 steel has high susceptibility to hydrogen embrittlement conditioned by a predominance of reversible traps in microstructure and by high hydrogen solubility. CT P P11 cell hydrogencharged charged asreceived received quasicleavage quasi cleavage solubility P1

The purinergic system participates in the control of blood pressure. Hypertension promotes the occurrence of gastrointestinal disorders such as intestinal inflammation and gastric emptying delay. This study aimed i) to investigate the participation of the P2X7 receptor blocker Brilliant Blue G (BBG) on gastric emptying of solids and changes in oxidative stress in the gastric fundus, duodenum, and colon of spontaneously hypertensive rats (SHR) and ii) to study the putative relationship of this effect with the renin-angiotensin system. Rats were divided into five groups: Control, SHR, SHR+BBG, SHR+BBG+ATP, and SHR+BBG+ANG II. In the gastrointestinal tract, we assessed gastric emptying (GE) and oxidative stress markers (NOx, MPO, GSH, SOD). We observed a decrease in the GE rate (P<0.05) in SHR vs control rats (21.8±2.0% vs 42.8±3.5%). The decrease in GE was returned (P<0.05) to control levels by BBG in SHR rats (21.8±2.0% vs 41.6±3.2%). Co-administration of ATP or ANG II together with BBG bypassed the effect of the P2X7 antagonist on GE in SHR (P<0.05) (21.9±5.0% vs 25.6±3.0% vs 41.6±3.2%). The MPO activity increased (P<0.05) in the gastric fundus of SHR compared to control rats (6.12±2.26 vs 0.077±0.02 UMPO/mg tissue); this effect was prevented (P<0.05) by BBG (0.55±0.15 vs 6.12±2.26 UMPO/mg tissue). Data demonstrated that blockage of P2X7 receptors with BBG can improve the GE delay and oxidative stress biomarkers in SHR animals. This preventive effect of BBG on GE delay was abrogated by ANG II and ATP, thus prompting crosstalk between renin-angiotensin and the purinergic signaling systems underlying this phenomenon. pressure i PX P X P2X (BBG duodenum (SHR ii reninangiotensin renin angiotensin groups Control SHRBBG SHR+BBG SHRBBGATP SHR+BBG+ATP SHRBBGANG tract (GE NOx, NOx (NOx GSH SOD. SOD . SOD) P<0.05 P005 0 05 (P<0.05 21.8±2.0% 21820 21 8 2 (21.8±2.0 42.8±3.5%. 42835 42.8±3.5% 42 3 5 42.8±3.5%) 41.6±3.2%. 41632 41.6±3.2% 41 6 41.6±3.2%) Coadministration Co administration 21.9±5.0% 21950 9 (21.9±5.0 25630 25 25.6±3.0 612226 12 26 (6.12±2.2 0077002 077 02 0.077±0.0 UMPOmg UMPO mg tissue tissue) 0.55±0.15 055015 55 15 (0.55±0.1 6.12±2.2 tissue. animals phenomenon P<0.0 P00 (P<0.0 21.8±2.0 2182 (21.8±2. 4283 42.8±3.5 4 4163 41.6±3.2 21.9±5.0 2195 (21.9±5. 2563 25.6±3. 61222 1 (6.12±2. 007700 07 0.077±0. 0.55±0.1 05501 (0.55±0. 6.12±2. P<0. P0 (P<0. 21.8±2. 218 (21.8±2 428 42.8±3. 416 41.6±3. 21.9±5. 219 (21.9±5 256 25.6±3 6122 (6.12±2 00770 0.077±0 0.55±0. 0550 (0.55±0 6.12±2 P<0 (P<0 21.8±2 (21.8± 42.8±3 41.6±3 21.9±5 (21.9± 25.6± 612 (6.12± 0077 0.077± 0.55±0 055 (0.55± 6.12± P< (P< 21.8± (21.8 42.8± 41.6± 21.9± (21.9 25.6 61 (6.12 007 0.077 0.55± (0.55 6.12 (P 21.8 (21. 42.8 41.6 21.9 25. (6.1 00 0.07 0.55 (0.5 6.1 21. (21 42. 41. (6. 0.0 0.5 (0. 6. (2 (6 0. (0 (

RESUMO Este estudo descreve a ocorrência de alteração reprodutiva em peixe da espécie Mugil curema, procedente da Baía da Babitonga, Santa Catarina. Macro e microscopicamente, foi identificada alteração no sistema reprodutivo, caracterizada pela presença de gônadas masculina e feminina, próximas da maturidade sexual, caracterizando um caso de intersexo. Não foi possível determinar os fatores que possam ter contribuído para o desenvolvimento dessa alteração reprodutiva, porém, como a espécie animal pode ter suas características de vida e reprodutiva influenciadas pela ação antrópica, é importante um estudo contínuo desses peixes nesse ambiente. Considerando o número de peixes dessa espécie que foram examinados (n=433), a prevalência estimada de intersexualidade foi de 0,23% (intervalo de confiança: 0,00 a 0,68%, com nível de confiança de 95%). Os achados deste estudo suportam o diagnóstico de intersexualidade em M. curema proveniente da Baía da Babitonga, sendo o primeiro caso documentado dessa condição nessa espécie na costa de Santa Catarina, Brasil. Babitonga Catarina microscopicamente reprodutivo feminina sexual intersexo porém antrópica ambiente n=433, n433 n n=433 , 433 (n=433) 023 0 23 0,23 intervalo 000 00 0,0 068 68 0,68% 95%. 95 95% . 95%) M Brasil n43 n=43 43 (n=433 02 2 0,2 0, 06 6 0,68 9 n4 n=4 4 (n=43 0,6 n= (n=4 (n= (n

ABSTRACT This study describes the occurrence of reproductive changes in a mullet (Mugil curema) from the Babibtonga Bay, Santa Catarina. Gross and microscopic findings indicated changes in the reproductive system that were characterized by the presence of both male and female gonads, nearing sexual maturity, which was compatible with the diagnosis of intersex. It was not possible to identify predisposing factors that may have contributed to the development of this condition. However, as this species of fish may have their reproductive development affected by anthropogenic influence, it is important to permanently monitor this kind of environment. Considering the number of fish belonging to this species that was examined (n=433), the estimated prevalence for intersexuality was 0.23% (confidence interval: 0.00 to 0.68%, with confidence level of 95%). The findings in this study support the diagnosis of intersexuality in M. curema from the Babitonga Bay, which is the first documented case of this condition in this species on the coast of Santa Catarina, Brazil. Mugil Bay Catarina gonads maturity intersex However influence environment n=433, n433 n n=433 , 433 (n=433) 023 0 23 0.23 interval 000 00 0.0 068 68 0.68% 95%. 95 95% . 95%) M Brazil n43 n=43 43 (n=433 02 2 0.2 0. 06 6 0.68 9 n4 n=4 4 (n=43 0.6 n= (n=4 (n= (n

6-Nitrodopamine is a novel catecholamine released by vascular tissues, heart, and vas deferens. The aim of this study was to investigate whether 6-nitrodopamine is released from the thoracic aorta and pulmonary artery rings of marmosets (Callithrix spp.) and to evaluate the relaxing and anti-contractile actions of this catecholamine. Release of 6-nitrodopamine, dopamine, noradrenaline, and adrenaline was assessed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The relaxations induced by 6-nitrodopamine and by the selective dopamine D2 receptor antagonist L-741,626 were evaluated on U-46619 (3 nM)-pre-contracted vessels. The effects of 6-nitrodopamine and L-741,626 on the contractions induced by electric-field stimulation (EFS), dopamine, noradrenaline, and adrenaline were also investigated. Both aorta and pulmonary artery rings exhibited endothelium-dependent release of 6-nitrodopamine, which was significantly reduced by the NO synthesis inhibitor L-NAME. Addition of 6-nitrodopamine or L-741,626 caused concentration-dependent relaxations of both vascular tissues, which were almost abolished by endothelium removal, whereas L-NAME and the soluble guanylate cyclase inhibitor ODQ had no effect on 6-nitrodopamine-induced relaxations. Additionally, pre-incubation with 6-nitrodopamine antagonized the dopamine-induced contractions, without affecting the noradrenaline- and adrenaline-induced contractions. Pre-incubation with L-741,626 antagonized the contractions induced by all catecholamines. The EFS-induced contractions were significantly increased by L-NAME, but unaffected by ODQ. Immunohistochemical assays showed no immunostaining of the neural tissue markers S-100 and calretinin in either vascular tissue. The results indicated that 6-nitrodopamine is the major catecholamine released by marmoset vascular tissues, and it acts as a potent and selective antagonist of dopamine D2-like receptors. 6-nitrodopamine release may be the major mechanism by which NO causes vasodilatation. 6Nitrodopamine Nitrodopamine 6 tissues heart deferens 6nitrodopamine nitrodopamine Callithrix spp. spp anticontractile anti contractile 6nitrodopamine, nitrodopamine, noradrenaline LCMS/MS. LCMSMS LC MS/MS . MS (LC-MS/MS) D L741,626 L741626 L 741,626 741 626 L-741,62 U46619 U 46619 U-4661 3 ( nMprecontracted nM pre contracted vessels electricfield electric field EFS, EFS , (EFS) investigated endotheliumdependent dependent LNAME. LNAME NAME. NAME concentrationdependent concentration removal 6nitrodopamineinduced nitrodopamineinduced Additionally preincubation incubation dopamineinduced adrenalineinduced Preincubation Pre catecholamines EFSinduced LNAME, NAME, S100 S 100 S-10 D2like Dlike like receptors vasodilatation LCMS LCMS/MS MSMS (LC-MS/MS L741 L741,62 L74162 741626 741,62 74 62 L-741,6 U4661 4661 U-466 (EFS S10 10 S-1 L74 L741,6 L7416 74162 741,6 7 L-741, U466 466 U-46 S1 1 S- L7 L741, 7416 741, L-741 U46 46 U-4 L-74 U4 4 U- L-7 L-

The objective of this study was to evaluate the chemical composition and in situ degradability of elephant grass silage dry matter with increasing levels of sugarcane bagasse. A completely randomized design was adopted with five treatments: 0, 5, 10, 15, and 20% inclusion of sugarcane bagasse on an as-fed matter basis, with five replications, totalling 25 experimental units. The increasing proportion of sugarcane bagasse analysed was favourable only in increasing the concentration of dry matter and fibre of silages and in maintaining a considerable crude protein content. In the in situ degradation assay, the addition of sugarcane bagasse in silage decreased the ruminal degradability of dry matter, and as the passage rates increased, the effective degradability decreased. In the in vitro gas production assay, the total production of gases was decreased with the inclusion of sugarcane bagasse, as did the degradability of organic matter and neutral detergent fibre. The recommendation for the inclusion of sugarcane bagasse should be analysed according to the desired objective, emphasizing that values higher than 5% can greatly compromise the final nutritive value of elephant grass silage.

ABSTRACT Some metallurgical wastes have residual metals of interest generated in metallurgical operations have values of interest that can be reprocessed to give additional value to the operation, this work presents the modeling and simulation of leaching tanks for silver recovery with thiourea and oxalate from jarosite that is principal zinc processing waste for this purpose first-order models were used and the one with the best fit was selected for the evaluation of the leaching rate in tanks with continuous stirring (CSTR). Finally, the results obtained with the process simulation are presented with the help of the Matlab-Simulink® software using subsystem blocks.

RESUMEN Algunos residuos generados en operaciones metalúrgicas tienen elementos metálicos de interés, por lo que pueden ser reprocesados para darle un valor adicional a la operación. Este trabajo presenta el modelamiento y simulación de tanques de lixiviación para la recuperación de plata con tiourea y oxalato a partir de jarositas que son uno de los principales desechos del procesamiento del zinc. Se usaron modelos de primer orden y se seleccionó el de mejor ajuste para la evaluación de la velocidad de lixiviación en tanques con agitación continua (CSTR). Finalmente se presentan los resultados obtenidos en la simulación del proceso con ayuda del software Matlab-Simulink® por medio de bloques de subsistemas.

The aim of the present study was to verify the role of lactate as a signaling molecule in cardiac tissue under physiological conditions. C57BL6/J male mice were submitted to acute running bouts on a treadmill at different exercise intensities (30, 60, and 90% of maximal speed - Smax) under the effect of two doses (0.5 and 5 mM) of α-cyano-4-hydroxycynnamate (CINN), a blocker of lactate transporters. Cardiac lactate levels, activity of the enzymes of glycolytic [hexokinase (HK) and lactate dehydrogenase (LDH)] and oxidative metabolism [citrate synthase (CS)], and expression of genes also related to metabolism [LDH, nuclear factor erythroid 2-related factor 2 (NRF-2), cytochrome oxidase IV (COX-IV), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)] were evaluated. Elevated cardiac lactate levels were observed after high intensity running at 90% of Smax, which were parallel to increased activity of the HK and CS enzymes and mRNA levels of PGC-1α and COX-IV. No changes were observed in cardiac lactate levels in mice running at lower exercise intensities. Interestingly, prior intraperitoneal administration (15 min) of CINN (0.5 mM) significantly reduced cardiac lactate concentration, activities of HK and CS, and mRNA levels of PGC-1α and COX-IV in mice that ran at 90% of Smax. In addition, cardiac lactate levels were significantly correlated to both PGC-1α and COX-IV cardiac gene expression. The present study provides evidence that cardiac lactate levels are associated to gene transcription during an acute bout of high intensity running exercise.

Resumo: Apresentamos a primeira lista de espécies de Odonata (Insecta) para o estado do Acre no Brasil, adicionando aspectos ecológicos e notas sobre o seu estado de conservação. O Acre é um dos estados com o menor esforço de coleta da região Norte do Brasil e uma área de importância geográfica, pois é uma transição entre os Andes e a Amazônia. Foram realizadas coletas em 35 riachos, distribuídos em nove municípios e também complementados com informações de dados secundários de revisão na literatura e bases de dados de coleções biológicas. Registramos 140 espécies, distribuídas em 55 gêneros, das quais 16 espécies são novos registros para o estado, tornando-o o segundo em número de espécies na região Norte do Brasil. Das espécies registradas, 113 estão classificadas dentro de alguma categoria de ameaça da lista vermelha da IUCN e 110 na lista nacional do ICMBio. Analisando as informações do conhecimento das espécies, o conhecimento das fêmeas e larvas ainda muito limitado e na maioria das vezes disponíveis apenas para os machos adultos. Pela primeira vez é registrada a ocorrência da Drepanoneura loutoni von Ellenrieder & Garrison (2008) no Brasil, também apresentamos fotos das principais estruturas, com comentários sobre sua biologia. Nosso trabalho mostra a importância da realização de estudos de biodiversidade em áreas ainda pouco estudadas como a do estado do Acre e serve como base para futuras expedições na região.

Abstract: Here we present the first Odonata (Insecta) species list for the state of Acre, Northern Brazil, adding ecological aspects and notes on its taxonomy and conservation status. Regarding Odonata samplings, Acre is one of the least explored states in the northern region of Brazil and an area of geographic importance, as it is a transition between the Andean and Amazon regions. Collections were carried out in 35 streams, distributed in nine municipalities. We also supplemented our database from the review of secondary literature and data from biological collections. We recorded 140 species, distributed in 55 genera, of which 16 species are new records for the state, making Acre state the second in the number of recorded species in northern Brazil. Of the recorded species, 113 are classified within some threat category of the IUCN red list and 110 in the ICMBio national list. Analyzing the taxonomic information on each recorded species, knowledge of females and larvae is still very limited and, most of the time, only available to adult males. For the first time, the occurrence of Drepanoneura loutonivon Ellenrieder & Garrison (2008) is reported for Brazil, and we also present photos of its main morphological characters, with comments on its biology. Our study shows the importance of conducting biodiversity research in poorly studied areas; such as the state of Acre, and serves as a basis for future expeditions in the region.

ABSTRACT It is essential to determine the productive potential and quality of forage sorghum (Sorghum bicolor (L.) Moench) silages using alternative and organic inputs, such as poultry litter (PL), intending to higher efficiency, and sustainable development of animal production systems in the world. Poultry litter fertilization has been widely used in crops for silage production, where it is believed that fertilization with PL can influence the fermentation profile and composition of forage sorghum silages. The objective of this study was to evaluate different levels of fertilization with PL on the agronomic and quality characteristics of forage sorghum silage ‘BRS Ponta Negra’. For determination of agronomic and productive characteristics, randomized blocks design was adopted, the treatments were different PL levels: 5, 10, and 15 Mg ha-1. While for the evaluation of silage characteristics, the design was completely randomized. With fertilizer doses, a linear increase was observed for plant height, stem diameter, leaf length, and consequently for fresh and DM productions. Linear reduction was observed for neutral detergent fiber, while crude protein and pH contents of silages increased linearly with PL levels. Quadratic effect occurred for gas and effluent losses. Poultry litter may be an alternative source to supply the N needs in the production of sorghum for silage under experimental similar conditions. Associating productivity with cultivation efficiency, the PL level 13.46 Mg ha-1 is recommended for presenting the highest N agronomic efficiency and good nutritional quality of the silage.

ABSTRACT In semi-arid zones, feedlots are considered a tool to minimize the impacts of seasonal forage on the production of sheep meat in the tropics. However, the use of alternative tropical ingredients as substitutes for corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) meal in formulations of confined sheep diets is recurrent. The aim of this study was to evaluate the effect of diets containing corn and soybean meal (CS), corn (CU), cassava (Manihot esculenta Crantz) root (CRU) or spineless cactus (Opuntia ficus-indica [L.] Mill., SCU) associated with urea on the performance, carcass characteristics and meat quality of confined lambs. Forty non-castrated Santa Inês sheep with average age of 150 d and average initial weight of 22.6 ± 2.3 kg were confined in individual pens for 76 d and slaughtered. The diets effects were contrasted by Tukey test. Empty body weight was different among the treatments (P < 0.05) and was 27.3, 25.3, 23.0 and 21.1 kg for the animals fed CS, CU, CRU and SCU, respectively. CS diet presented higher cold carcass weights while SCU diet presented lower cold carcass weights (P < 0.05) (11.37 kg) and higher cooling losses. Luminosity, yellow color intensity and meat moisture content were higher (P < 0.05) in SCU than CS. Liver, skin and internal fat weights were similar (P > 0.05) in CU and CRU, but higher (P < 0.05) than SCU. The replacement of corn and soybean meal for different carbohydrate sources associated with urea reduces the body weight components in confined sheep.

Abstract 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.

Abstract 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.