ABSTRACT The development of aquaculture through the cultivation of what are considered unconventional species is an option with the potential to solve the problem of food scarcity. The aim of the present study was to evaluate the zootechnical performance of juvenile Pomacea haustrum fed different commercial diets, and subjected to different levels of salinity. After seven P. haustrum spawn had hatched in the laboratory, the juveniles were randomly selected and transferred to the rearing containers. Two different commercial diets were offered: rabbit feed with a high proportion of ingredients rich in crude vegetable protein (VP), and dog food containing balanced levels of ingredients rich in crude vegetable and animal protein (MP). The selected juveniles were randomly stocked at different salinities (0, 2 and 4 parts per thousand - ppt). The experiment lasted 65 days. Twenty-one hours after the start of the experiment, 100% of the individuals reared at a salinity of 4 ppt had died. There was a significant difference (p ≤ 0.05) between the results for zootechnical performance (average final weight, weight gain, average final growth, specific growth rate, protein efficiency and apparent feed conversion) for animals reared in fresh water or at a salinity of 2 ppt, regardless of the type of diet. The origin of the protein in the diet had no significant effect on the zootechnical performance of the individuals; however, the salinity of the water impaired development of the animals in direct proportion to its concentration. scarcity P laboratory containers offered VP, VP , (VP) MP. MP . (MP) 0, 0 (0 ppt. ppt) 6 days Twentyone Twenty one 100 died p 0.05 005 05 gain rate conversion however concentration (VP (MP ( 10 0.0 00 1 0.

Resumen El playero blanco (Calidris alba) es el ave playera de más amplia distribución que inverna en ambas costas de América, con registros de individuos vagabundos en el interior del continente. El 14 de septiembre de 2022, observamos y fotografiamos dos juveniles del playero blanco en una charca pequeña adyacente al Río Mezquites en el Área de Protección de Flora y Fauna de Cuatro Ciénegas, Coahuila, México. Este avistamiento representa el primer registro de esta especie en este sitio RAMSAR e incrementa su distribución continental conocida en el noreste de México, siendo además el primero documentado para el estado de Coahuila.

Abstract The Sanderling (Calidris alba) is the most widely distributed shorebird that winters on both coasts of America, with records of vagrant individuals in the interior of the continent. On 14 September 2022, we observed and photographed two juvenile Sanderlings at a small pool adjacent to the Río Mezquites in the Cuatro Ciénegas protected area, Coahuila, Mexico. This sighting represents the first record of this species in this RAMSAR site, and increases the known inland distribution in northeastern Mexico, as well as the first documented for the state of Coahuila.

Abstract Introduction: Semaprochilodus laticeps is a freshwater fish species native to the Orinoco Basin that is exploited in Colombia at two different stages of its life cycle: fry (for the ornamental trade) and adults (for the consumer market). This double exploitation of juveniles and adults raises concerns about the population stability of the species. Objective: To evaluate the sustainability of the exploitation of the species in these two life stages. Methods: 1 277 specimens of S. laticeps were sampled between June and December 2017. Population parameters were estimated from length-frequency data using ELEFAN 1 routine of the FISAT II package. Length at first maturity (Lm) and length at maximum yield (Lopt) were determined using the Froese and Binohlan equations. Virtual population analysis was performed based on Jones length cohort analysis. Results: Population parameters were as follows: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 yr-1, M = 1.24 yr-1 and F = 1.68. Lm was estimated to be 29.6 cm SL and Lopt at 33.4 cm SL. Of note, 96.3 % of the fish caught in the consumer fishery exceeded Lm and 80 % exceeded Lopt. The results of the virtual population analysis suggested that a very low proportion (0.85 %) of the population was caught as fry, possibly due to natural mortality. Conclusions: Based on the results, as no indicators of overexploitation were identified, it is recommended to continue with the dual use of S. laticeps. It is recommended to maintain the existing conservation measures, such as the closed season during the reproductive period, to ensure sustainable fishery exploitation. The results obtained can serve as a reference to analyze the situation of other species currently fished for both the ornamental (fry) and food (adult) markets.

Resumen Introducción: Semaprochilodus laticeps es una especie de pez de agua dulce originaria de la cuenca del Orinoco, explotada en Colombia en dos etapas distintas de su ciclo de vida: alevín (para el comercio ornamental) y adulto (para el mercado de consumo). Esta doble explotación de alevines y adultos genera preocupación sobre la estabilidad poblacional de la especie. Objetivo: Evaluar la sostenibilidad de la explotación de la especie en estas dos etapas de vida. Método: Entre junio y diciembre de 2017 se muestrearon 1 277 ejemplares de S. laticeps. Los parámetros poblacionales se estimaron utilizando datos de frecuencia de tallas con la rutina ELEFAN 1 del paquete FISAT II. La longitud de primera madurez (Lm) y la de máximo rendimiento (Lopt) se determinaron mediante ecuaciones de Froese y Binohlan. El análisis de la población virtual se realizó basándose en el análisis de cohorte de longitud de Jones. Resultados: Los parámetros poblacionales fueron los siguientes: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 año-1, M = 1.24 año-1 y F = 1.68. Lm se estimó en 29.6 cm SL y Lopt en 33.4 cm SL. En particular, el 96.3 % del pescado capturado en la pesquería de consumo superó Lm y el 80 % superó Lopt. El análisis de la población virtual sugirió que una fracción muy baja (0.85 %) de la población fue capturada como alevines, posiblemente atribuible a la mortalidad natural. Conclusiones: Con base en los hallazgos, al no identificarse indicadores de sobreexplotación, se recomienda continuar con el doble uso de S. laticeps. Se recomienda mantener las medidas de protección existentes, así como una veda durante el período reproductivo, para garantizar una explotación pesquera sostenible. Los resultados obtenidos pueden servir como referencia para analizar la situación de otras especies actualmente capturadas para el mercado tanto ornamental como de consumo.

Abstract Introduction: The currents of streams and rivers are natural signals that influence the migrations in the life cycle of amphidromous shrimp. Objective: To evaluate the rheotaxis behavior in juveniles and adults of Macrobrachium tenellum, in relation to their response capacity to different water currentspeeds in a closed-loop experimental system. Methods: A PVC pipe system was used, with a tub for water recirculation and a backwater placed in the middle of the system. Water flows of 10-30 cm/s were tested to establish the experimental conditions. Rheotaxis behavior without backwater (SR) and with backwater (CR) was evaluated; three water flows were tested: FI, 14 cm/s; FII, 18.7 cm/s; and FIII, 22.1 cm/s, and a control FC flow, 0 cm/s, with 40 juveniles, 40 females and 40 males per flow. Three main behaviors were identified: positive rheotaxis, negative rheotaxis, and no reaction. Results: For both SR and CR, water flows stimulate positive rheotaxis and the behavioral response is different depending on the speed of the water flow and whether they are juveniles, females, or males. In CR there was a greater response of the prawns to continue swimming against the current when they entered the pool. At a straight angle, the constant flow of water greater than 23.2 cm/s makes it difficult for this species to swim against the current. Conclusions: The positive rheotaxis response was the most prevalent in juveniles, females, and males of M. tenellum.

Resumen Introducción: Las corrientes de arroyos y ríos son señales naturales que influencian las migraciones en el ciclo de vida de langostinos anfídromos. Objetivo: Evaluar el comportamiento de reotaxis en juveniles y adultos de Macrobrachium tenellum, con relación a su capacidad de respuesta a diferentes velocidades de flujos de corriente de agua en un sistema experimental de circuito cerrado. Métodos: Se utilizó un sistema de tubos PVC, con una tina para la recirculación del agua y un remanso colocado a la mitad del sistema. Se probaron flujos de agua de 10-30 cm/s para establecer las condiciones experimentales. Se evaluó el comportamiento de reotaxis sin remanso (SR) y con el remanso (CR); se probaron tres flujos de agua: FI, 14 cm/s; FII, 18.7 cm/s; y FIII, 22.1 cm/s, y un flujo control FC, 0 cm/s, con 40 juveniles, 40 hembras y 40 machos por flujo. Se identificaron tres comportamientos principales: reotaxis positiva, reotaxis negativa y sin reacción. Resultados: Tanto para SR como CR los flujos de agua estimulan mayormente la reotaxis positiva y la respuesta de comportamiento es diferente según la velocidad del flujo de agua y si son juveniles, hembras o machos. En CR hubo una mayor respuesta de los langostinos a seguir nadando en contra de la corriente cuando estos ingresaban al remanso. En un ángulo recto, el flujo de agua constante superior a 23.2 cm/s dificulta el nado contra corriente de esta especie. Conclusiones: La respuesta de reotaxis positiva fue la que mayor predominó en juveniles, hembras y machos de M. tenellum.

Abstract Introduction: Morelet’s crocodile (Crocodylus moreletii) is a species distributed in the Mexican southeast and threatened due to multiple pressures. Objective: To characterize the digestive proteases in the acid phase (stomach) and alkaline phase (intestine) of three life stages of C. moreletii in captivity (hatchling, juvenile, and adult). Methods: Total alkaline and acid protease activities were quantified using casein and haemoglobin as substrates. Trypsin, chymotrypsin, leucine aminopeptidase, and elastase activities were quantified using synthetic substrates. Protease profiles were analysed by SDS-PAGE and Native-PAGE. Results: The specific activity of acid and alkaline proteases showed differences between the three stages, finding the highest activity in the juveniles. Trypsin, chymotrypsin, leucine aminopeptidase, and elastase activities were higher in hatchlings. There were differences in optimum pH and temperature of acid and alkaline proteases, trypsin, and leucine aminopeptidase between the three stages, demonstrating the diversification of the enzymes according to different stages, as well as the presence of specific isoforms in each stage of C. moreletii. The acid phase zymogram showed four bands with pepsin-like acid activity in the hatchling and juvenile crocodile, while in the adult only two of the four bands were detected. The alkaline zymogram showed that the hatchling had the highest number of activity bands compared to the other stages, corresponding to the high specific activity reported in the alkaline phase. Conclusions: Digestive proteases of Morelet’s crocodile differ in their biochemical characteristics and the number of proteases between hatchling, juvenile, and adult. This could help in the future design of balanced diets as well to the sustainable management and production of this species.

Resumen Introducción: El cocodrilo de pantano (Crocodylus moreletii) es una especie distribuida en el sureste mexicano y amenazada por múltiples presiones. Objetivo: Caracterizar las proteasas digestivas en fase ácida (estómago) y fase alcalina (intestino) en tres etapas de vida de C. moreletii en cautiverio (cría, juvenil y adulto). Métodos: Se cuantificaron las actividades de proteasas alcalinas y ácidas totales utilizando caseína y hemoglobina como sustrato. Las actividades de tripsina, quimotripsina, leucina aminopeptidasa y elastasa se cuantificaron utilizando sustratos sintéticos. Los perfiles de proteasas se analizaron mediante SDS-PAGE y PAGE nativa. Resultados: La actividad específica de las proteasas ácidas y alcalinas mostró diferencias entre las tres tallas, encontrándose la mayor actividad en el estadio juvenil. Las actividades de tripsina, quimotripsina, leucina aminopeptidasa y elastasa fueron mayores en las crías. Hubo diferencias en el pH y temperatura óptimos de las proteasas ácidas y alcalinas, tripsina y leucina aminopeptidasa entre las tres tallas, demostrando la diversificación de las enzimas según las diferentes tallas, así como la presencia de isoformas específicas en cada talla de C. moreletii. El zimograma en fase ácida mostró cuatro bandas con actividad similar a pepsina en la cría y juvenil, mientras que en el adulto solo se detectaron dos de las cuatro bandas. El zimograma alcalino mostró que la cría tuvo el mayor número de bandas de actividad en comparación con las otras tallas, correspondiente a la alta actividad específica reportada en la fase alcalina. Conclusiones: Las proteasas digestivas del cocodrilo de pantano presentaron características bioquímicas y en número de proteasas diferentes entre cría, juvenil y adulto. Esto podría ayudar en el futuro diseño de dietas balanceadas, así como al manejo y producción sustentable de esta especie.

SUMMARY: The study was designed to explore the association between the immunolocalization of alpha-smooth muscle actin (α- SMA) and S100 proteins within the efferent ductules (ED) from one side, and the sexual maturity and seasonality from the other side. For each season, tissue specimens were obtained from 7 adult and 7 juvenile, clinically healthy male dromedaries. Specimens were investigated by the standard immunohistochemical procedures. The immunohistochemical findings displayed that the pattern of expression was similar for both proteins, either in adults or in juveniles. Expression was significantly higher in adults during season of sexual activity (winter), fairly reduced during periods of transition from activity to inactivity (spring) or from inactivity to activity (autumn) and reaches its lowest magnitude during season of sexual inactivity (summer). On the other hand, a moderate immunoreactivity of both proteins in ED from juvenile male camels was nearly uniform throughout the year. The immunoreactivity for both α-SMA (smooth muscle cells in ductular and vascular walls) and S100 (ductular ciliated cells), was evident during periods of sexual activity. It can be concluded that the immunoreactivity is androgen- dependent and positively correlated with both of sexual activity and maturity, suggesting a crucial role of both α-SMA and S100 proteins in the regulation of the diverse functions of the ED in male dromedaries.

RESUMEN: El estudio fue diseñado para explorar la asociación entre la inmunolocalización de la actina de músculo liso alfa (α-SMA) y las proteínas S100 dentro de los conductos eferentes (ED) por una pate, y la madurez sexual y estacionalidad por otra parte. Para cada estación, se obtuvieron muestras de tejido de 7 dromedarios machos adultos jóvenes y clínicamente sanos. Las muestras se investigaron mediante procedimientos inmunohistoquímicos estándar. Los hallazgos inmunohistoquímicos mostraron que el patrón de expresión era similar para ambas proteínas, ya sea en adultos o en jóvenes. La expresión fue significativamente mayor en adultos durante la temporada de actividad sexual (invierno), bastante reducida durante los períodos de transición de actividad a inactividad (primavera) o de inactividad a actividad (otoño) y alcanzaba su magnitud más baja durante la temporada de inactividad sexual (verano). Por otro lado, una inmunorreactividad moderada de ambas proteínas en el DE de camellos machos juveniles fue casi uniforme durante todo el año. La inmunorreactividad tanto para α-SMA (células musculares lisas en las paredes ductulares y vasculares) como para S100 (células ciliadas ductulares), fue evidenciada durante los períodos de actividad sexual. Se puede concluir que la inmunorreactividad es dependiente de los andrógenos y se correlaciona positivamente tanto con la actividad sexual como con la madurez, lo que sugiere un papel crucial de las proteínas α-SMA y S100 en la regulación de las diversas funciones del DE en dromedarios machos.

SUMMARY: Morphological dimensions are reliable representations of the functioning, growth, and development of the skeletal- muscular system, defining a significant role in the sport of volleyball. In volleyball, it is imperative to identify the anthropometric constitution generated by endogenous and exogenous factors. The aim of the study was to determine the differences in morphological characteristics between junior and senior members of the BIH national team. The sample of respondents included 29 male volleyball players from the national team of BIH, divided into a subsample of seniors (n=13; Body Height = 194.77 ± 7.01 cm; Body weight = 92.92 ± 7.02 kg) and a subsample of juniors (n=16, Body Height = 197.06±4.65cm; Body weight = 83.19±5.15 kg). Thirteen (13) variables of anthropometric space were measured. Anthropometric measurements were conducted following the ISAK standard procedure guidelines. The standard metric instruments were applied: Stadiometer (SECA 213, Germany) - used for measuring body height; Body mass was measured by a digital scale (Tefal/0-160kg); Circumference measurements were measured with a foldable non-elastic tape measure and a Gullick Tape (Baseline Measurement Tape/300cm) and a Calliper measured skin folds. The T-test results revealed statistically significant differences (approximately 54%) between the senior and junior players in various anthropometric measurements, including weight (T=4.307, p<0.001), leg length (T= - 4.251, p<0.001), hand length (T=2.661, p<0.015), upper arm circumference (T= 4.514, p<0.001), forearm circumference (T=5.275, p<0.001), upper arm skinfold (T= 5.741, p<0.001), and abdominal skinfold (T= 3.098, p<0.009). The male volleyball national team of VIH's senior players displayed superior anthropometric attributes compared to their junior counterparts. Identifying discrepancies at an early stage can optimize both the training regimen and the process of selecting players at a young age.

RESUMEN: Las dimensiones morfológicas son representaciones confiables del funcionamiento, crecimiento y desarrollo del sistema músculo-esquelético, definiendo un papel importante en el deporte del voleibol. En el voleibol es imperativo identificar la constitución antropométrica generada por factores endógenos y exógenos. El objetivo del estudio fue determinar las diferencias en las características morfológicas entre los miembros junior y senior del equipo nacional de BIH. La muestra de encuestados incluyó 29 jugadores de sexo masculino de voleibol del equipo nacional de BIH, divididos en una submuestra de mayores (n=13; altura corporal = 194,77 ± 7,01 cm; peso corporal = 92,92 ± 7,02 kg) y una submuestra de juveniles (n =16, Altura corporal = 197,06±4,65 cm; Peso corporal = 83,19±5,15 kg). Se midieron trece (13) variables del espacio antropométrico. Las mediciones antropométricas se realizaron siguiendo las pautas de procedimiento estándar de ISAK. Se aplicaron los instrumentos métricos estándar: estadiómetro (SECA 213, Alemania), utilizado para medir la altura corporal; La masa corporal se midió con una báscula digital (Tefal/ 0-160 kg); Las mediciones de la circunferencia se midieron con una cinta métrica plegable no elástica y una cinta Gullick (cinta métrica de referencia/300 cm) y un calibrador midió los pliegues de la piel. Los resultados de la prueba T revelaron diferencias estadísticamente significativas (aproximadamente 54 %) entre los jugadores senior y junior en varias medidas antropométricas, incluido el peso (T=4,307, p<0,001), la longitud de las piernas (T= -4,251, p<0,001), longitud de la mano (T=2,661, p<0,015), circunferencia del brazo (T= 4,514, p<0,001), circunferencia del antebrazo (T=5,275, p<0,001), pliegue cutáneo del brazo (T= 5,741, p<0,001), y pliegue cutáneo abdominal (T= 3,098, p<0,009). Los jugadores senior del equipo nacional masculino de voleibol de VIH mostraron atributos antropométricos superiores en comparación con sus homólogos juveniles. Identificar discrepancias en una etapa temprana puede optimizar tanto el régimen de entrenamiento como el proceso de selección de jugadores a una edad temprana.

SUMMARY: In current study, we used Nissl staining to examine the histological structure of the juvenile Chinese alligator brain, and immunohistochemistry (IHC) staining to detail the serotonin (5-hydroxytryptamine, 5-HT) localization and morphology of neurons belonging to the serotonergic system. Nissl staining revealed that the Chinese alligator brain was divided into four regions (telencephalon, diencephalon, brainstem, and cerebellum) and a connected ventricular system (containing the pair of lateral ventricles, third ventricle, fourth ventricle and the aqueduct). According to the IHC results, 5-HT immunoreactive (5-HT-IR) neurons were primarily observed in the cerebral cortex, the hypothalamic paraventricular nucleus (PH), tectum and tegmentum of the optic lobes, the medial longitudinal fasciculus (Flm) of medulla oblongata and the cerebellar cortex. 5-HT-IR fibers were mostly located lateral to the hypothalamic paraventricular nucleus (PH), in the medial vestibular nucleus (MVe) of the medulla oblongata, and in the choroid plexus (CP) of the lateral ventricles. Additionally, our findings paralleled those results of other reptiles; nevertheless, some distinctions in terms of both histological architecture and function were identified. The layering of the cerebral cortex and tectum, as well as the arrangement of Purkinje cells, differed between reptile brains. The distribution of 5-HT-IR neurons varied in the layer of cerebral and cerebellar cortex when compared to other reptiles. Within the diencephalon, 5-HT-IR neurons formed distinct nuclei in the hypothalamic paraventricular nucleus (PH), but few in the infundibular recess.

RESUMEN: Utilizamos la tinción de Nissl para examinar la estructura histológica del cerebro juvenil del caimán chino y la tinción inmunohistoquímica (IHC) para detallar la localización y morfología de la serotonina (5-hidroxitriptamina, 5-HT) de las neuronas que pertenecen al sistema serotoninérgico. La tinción de Nissl reveló que el cerebro del caimán chino estaba dividido en cuatro regiones (telencéfalo, diencéfalo, tronco encefálico y cerebelo) y un sistema ventricular conectado (que contiene el par de ventrículos laterales, el tercer ventrículo, el cuarto ventrículo y el acueducto). Según los resultados de IHC, las neuronas inmunorreactivas 5-HT (5-HT-IR) se observaron principalmente en la corteza cerebral, el núcleo paraventricular (PH) hipotalámico, el tectum y tegmento de los lóbulos ópticos, el fascículo longitudinal medial (Flm) de médula oblonga y la corteza cerebelosa. Las fibras 5-HT-IR se ubicaron principalmente lateral al núcleo paraventricular (PH) hipotalámico, en el núcleo vestibular medial (MVe) de la médula oblonga y en el plexo coroideo (CP) de los ventrículos laterales. Además, nuestros hallazgos fueron semejantes a los resultados obtenidos de otros reptiles; sin embargo, se identificaron algunas distinciones en términos tanto de arquitectura histológica como de función. Las capas de la corteza cerebral y el tectum, así como la disposición de las neuronas purkinjenses, diferían entre los cerebros de los reptiles. La distribución de las neuronas 5-HT-IR varió en la capa de la corteza cerebral y cerebelosa en comparación con otros reptiles. Dentro del diencéfalo, las neuronas 5-HT-IR formaron núcleos distintos en el núcleo paraventricular (PH) hipotalámico, pero pocos en el receso infundibular.

ABSTRACT. Due to its beneficial biological properties, chitosan extracted from crustacean byproducts emerges as a viable strategy to mitigate the anti-nutritional factors in vegetable-based diets for juvenile white snook (Centropomus viridis). The growth, survival, and nutritional efficiency of juvenile white snook-fed diets containing chitosan were evaluated. Chitosan was extracted chemically and enzymatically from shrimp byproducts (exoskeletons and heads). It was then included in a soybean meal-based diet (48% protein and 19% kJ g-1 gross energy) at 0, 0.5, and 1.0% chitosan levels (D-Control, CHI-0.5%, and CHI-1.0%). Juvenile snook (initial weight: 44.5 ± 4.2 g) were randomly distributed into 300 L tanks and fed the experimental diets three times daily for 45 days. Fish fed the CHI-0.5% and CHI-1.0% diets were significantly (P < 0.05) higher in growth rates than the D-Control diet. No significant differences in survival were observed. The FCR of the CHI-0.5% and CHI-1.0% diets were lower when compared to the D-Control (P < 0.05). The results suggest the utilization of chitosan in diets with high soybean meal content for snook to obtain better growth and survival.

ABSTRACT. The objective was to evaluate the effect of probiotic consortium technology (PCT) on the performance of Penaeus vannamei juveniles in the biofloc system in a short time. The experiment had four treatments with four replicates. In each experimental unit, 35 animals (3.15 ± 0.53 g and 7.80 ± 0.54 cm) were stocked in a biofloc system for 35 days. The treatments were: control - control without probiotic; PCT1 - probiotic in the diet (3 mL kg-1) and water (0.5 ppm - three times a week); PCT2 - probiotic in the diet (3 mL kg-1) and water (1 ppm - daily), and PCT3 - probiotic in the water (1 ppm - daily). For water quality and Vibrio, no significant differences were observed among treatments (P > 0.05). Regarding the zootechnical performance, the treatments with the probiotic promoted higher final biomass, biomass gain, and a more efficient feed conversion rate (P < 0.05). The performance improvement promoted by the probiotic may be related to increased concentrations of amylases, chymotrypsin, and lipases in the hepatopancreas (P < 0.05). It was concluded that PCT2 promoted the best zootechnical performance of P. vannamei during the grow-out phase in the biofloc system.

RESUMO Introdução: o salto e o agachamento são movimentos recorrentes nos processos de treinamento de um atleta, por isso é necessário compreender as variáveis que interagem no desenvolvimento dos objetivos de desempenho. Objetivo: determinar a relação entre a altura do salto e as variáveis mecânicas do agachamento. Materiais e métodos: a metodologia utilizada é do tipo correlacional quantitativa, com desenho transversal, onde 43 atletas juvenis (homens = 34, mulheres = 9) são avaliados nos testes de salto com contra-movimento (CMJ), agachamento médio. (SJ) e salto livre, juntamente com isso foram realizadas 6 repetições de agachamento em velocidade máxima, onde foi considerada a melhor repetição possível. Resultados: como principais resultados, obteve-se a relação significativa entre a velocidade propulsiva média e o CMJ (r=0,75, p: 0,00), SJ (r=0,69, p: 0,00) e livre (r=0,72, p: 0,00). Conclusões: por fim conclui-se que existe relação entre a capacidade de salto e a velocidade de execução do agachamento.

ABSTRACT Introduction: jumping and squatting are recurrent movements within the training processes of an athlete, which is why it is necessary to understand the variables that interact in the development of performance objectives. Objective: to determine the relationship between jump height and the mechanical variables of the squat. Materials and methods: the methodology used is of a quantitative correlational type, with a cross-sectional design, where 43 juvenile athletes (men = 34, women = 9) were evaluated in the counter-movement jump (CMJ), half squat jump (SJ) and free jump test, along with this, 6 repetitions of squats at maximum speed were performed, where the best possible repetition was considered. Results: the main results obtained were the significant relationship between the mean propulsive velocity and the CMJ (r =0.75, p: 0.00), SJ (r =0.69, p: 0.00) and free (r =0.72, p: 0.00). Conclusions: finally, it is concluded that there is a relationship between jumping capacity and the squat execution speed.

RESUMEN Introducción: el salto y la sentadilla son movimientos recurrentes dentro de los procesos de entrenamiento de un deportista, por lo cual, se hace necesario comprender las variables que interactúan en el desarrollo de los objetivos de rendimiento. Objetivo: determinar la relación de la altura del salto con las variables mecánicas de la sentadilla. Materiales y métodos: la metodología utilizada es de tipo cuantitativa correlacional, con un diseño transversal, donde se evalúan a 43 deportistas juveniles (hombres = 34, mujeres = 9), en las pruebas de salto en contra movimiento (CMJ), salto de media sentadilla (SJ) y salto libre, junto con esto, se ejecutaron 6 repeticiones de sentadillas a máxima velocidad, donde se consideró la mejor repetición posible. Resultados: se obtuvieron, como principales resultados, la relación significativa entre la velocidad media propulsiva y el CMJ (r=0.75, p: 0.00), SJ (r=0.69, p: 0.00) y libre (r=0.72, p: 0.00). Conclusiones: finalmente, se concluye que existe una relación entre la capacidad de salto y la velocidad de ejecución de la sentadilla.

Abstract The nematicidal effect of Canavalia ensiformis seed extract combined with silicon dioxide nanoparticles was evaluated on second instar juveniles of Meloidogyne incognita, a phytopathogenic nematode that affects tomato crops. In the first experiment, concentrations of the extract were tested at 2, 4, 6, 6, 8 and 10%, observing that the most effective concentration was 10%, with 90% mortality at 24 hours. In the second experiment, concentrations of the extract at 1.5, 2.0, 2.5 and 3.0% were combined with silicon dioxide nanoparticles at 0.06, 0.08, 0.10, 0.12 and 0.14%, where the most effective was 1.5% extract with 0.14% nanoparticles, which showed a mortality of 94% at 72 hours. These results suggest that the combination of C. ensiformis extract with NP's can be a strategy for the management of M. incognita in tomato crops.

Resumen Se evaluó el efecto nematicida del extracto de semillas de Canavalia ensiformis combinado con nanopartículas de dióxido de silicio, en juveniles de segundo estadio (J2) de Meloidogyne incognita, nematodo fitopatógeno que afecta el cultivo de tomate. En el primer experimento, se probaron concentraciones del extracto al 2, 4, 6, 8 y 10%, observando que la concentración más efectiva fue del 10%, con una mortalidad del 90% a las 24 horas. En el segundo experimento, se combinaron concentraciones del extracto al 1.5, 2.0, 2.5 y 3.0% con nanopartículas de dióxido de silicio al 0.06, 0.08, 0.10, 0.12 y 0.14%, donde la más eficaz fue la de 1.5% de extracto con 0.14% de nanopartículas, que mostró una mortalidad del 94% a las 72 horas. Estos resultados sugieren que la combinación de extracto de C. ensiformis con las NP’s puede ser una estrategia para el manejo de M. incognita en cultivos de tomate.

ABSTRACT Integrative studies are important for a better understanding of the functional development of fish digestive systems and the consequent design of suitable feeding regimes and ad-hoc diets. To characterize the ontogeny of digestive function in larvae and juveniles of two atherinopsids from South America, Odontesthes bonariensis and O. hatcheri, morphologic, histologic, and intestinal enzyme biochemical analyses were performed. Both species showed a functional digestive system from one week after hatching (wah) with a sustained high-level activity of the cytosolic enzyme leucine alanine peptidase (leu-ala) until 9 and 13 wah in O. hatcheri and O. bonariensis, respectively. Maximum specific leu-ala activities in both species were higher compared to other agastric and most gastric fish. These results and the abundant pinocytic vacuoles in the posterior intestine suggest that cytosolic digestion is crucial for these species. It seems that their apparent anatomically simple digestive system is compensated by an uncommonly early development and function of the digestive tract and accessory organs accompanied by high intestinal cytosolic activity. The above findings contribute to the understanding of the Atherinopsidae digestive model and, for the first time, suggest that under farming conditions, these species could be weaned at an early developmental stage with an appropriate balanced diet.

ABSTRACT Taurine supplementation has shown survival and feeding efficiency in larval fish development. Thus, the present study aims to evaluate the effects of adding taurine to the longfin yellowtail (Seriola rivoliana) diet for 60 days. Fish (n = 270) were distributed in three treatments: T0 without taurine, T1, and T2, supplemented with taurine at 1 and 2%, respectively. Growth performance, blood serum biochemistry, fatty acid, and amino acid profiles in skeletal muscle were evaluated. Notable improvements (P < 0.05) were observed in T1 and T2 in terms of specific growth rate (SGR) and weight gain (WG). Survival rates (SR) did not show significant differences (P > 0.05). In addition, a decrease was observed in intraperitoneal fat (IPF). Still, an increase was observed in blood parameters, including higher total protein (TP) and globulin (GLO) concentration, as well as a reduction in cholesterol (CHO) levels. Changes in fatty acid profiles were also detected in skeletal muscle with an increase in omega-3 fatty acids (EPA and DHA) and elevation in taurine concentration in T2. The results showed that adding 20 g kg-1 of taurine to the diet improved growth, skeletal muscle, and blood serum biochemistry. Therefore, the use of higher taurine concentrations is recommended in future studies to understand fully the extent of the benefits to longfin yellowtail juveniles.

Resumen: El artículo discute hasta qué punto los origines sociales determinan los recorridos escolares y de la participación social de los jóvenes, en el Portugal contemporáneo. Para ello, en primer lugar, se procede a una colección de diferentes líneas de investigación que, en Portugal e a nivel internacional, han abordado esta cuestión. Se explican los protocolos metodológicos y, en seguida, se presenta y se discute un conjunto de datos colegidos por un cuestionario aplicado por la Dirección-General de Estadísticas de Educación y Ciencia a una muestra nacional de estudiantes en el 10.º año de escolaridad (n=241.341). Los resultados apuntan a recorridos escolares y, en menor medida, también tasas de participación social aún marcados por desigualdades familiares, en un padrón de sucesivas (des)ventajas que se acumulan a lo largo de las trayectorias infantiles y juveniles.

Resumo: O presente artigo discute até que ponto as origens sociais são condicionantes dos percursos escolares e de participação social dos jovens, no Portugal contemporâneo. Para isso, num primeiro momento, procede a um levantamento de diferentes filões de pesquisa que, a nível nacional e internacional, têm abordado esta questão. Explicitam-se os protocolos metodológicos e, em seguida, apresenta-se e discute-se um conjunto de dados obtidos a partir de um inquérito aplicado pela Direção-Geral de Estatísticas da Educação e Ciência a uma amostra nacional dos estudantes no 10.º ano de escolaridade (n= 241.341). Os resultados apontam para percursos escolares e, em menor escala, indicam, também, taxas de participação social ainda bastante marcados por desigualdades familiares, num padrão de sucessivas (des)vantagens que se vão acumulando ao longo das trajetórias infantis e juvenis.

Abstract: This article analyses how social background frames young people’s schooling pathways and social participation patterns in contemporary Portugal. With such aim, firstly, it provides a collection of how different research streams, in Portugal and internationally, address this question. The methodological protocols are explained, and afterwards, a set of data from a survey carried out by DG Education and Science Statistics to a national sample of students in 10th grade (n=241.341) is presented and discussed. The results point to schooling pathways and, to a lesser extent, social participation rates strongly bounded by family inequalities in a pattern of consecutive and cumulative (dis)advantages throughout young people’s trajectories.