Biodisponibilidad de los ácidos grasos de cadena corta: mecanismos de absorción

Los ácidos grasos de cadena corta (AGCC) son ácidos monocarboxílicos con una cadena de uno a seis átomos de carbono saturados. Son los principales aniones del colon. Se presentan como ácidos libres en el tracto gastrointestinal de los mamíferos, siendo el producto fi nal de la digestión microbiana de los carbohidratos. Los índices de producción microbiana y de absorción son tan altos que los AGCC son la mayor fuente de energía (70-80%) en mamíferos como la vaca. La contribución de los AGCC a los requerimientos del metabolismo basal de los animales monogástricos depende de factores como la concentración y las cantidades totales de los mismos, índices de producción y absorción y la capacidad relativa del segmento intestinal considerando el peso del cuerpo del individuo. Además de su papel energético, van a intervenir en diversos procesos como el transporte de agua y electrolitos en el colon. Debido a su carácter hidrofílico, los ratios y mecanismos de absorción de estos ácidos son claramente diferenciables de los ácidos grasos de cadena larga liposolubles. En este artículo se hace un repaso a la funcionalidad de los ácidos grasos de cadena corta y sus mecanismos de absorción por difusión pasiva como por transporte activo.Short chain fatty acids (SCFA) are monocarboxylic acids with a chain from one to six carbon atoms saturated. Are the major anions of the colon. Present as free acids in the gastrointestinal tract of mammals, the final product of microbial digestion of carbohydrates. The rates of microbial production and absorption are so high that the SCFA are the major source of energy (70-80%) in mammals such as cows. The contribution of SCFA to the requirements of basal metabolism of monogastric animals depends on factors such as concentration and the total amounts thereof, production and absorption rates and the relative ability of the intestinal segment considering the individual’s body weight. Besides its role energy will participate in various processes such as transport of water and electrolytes in the colon. Due to their hydrophilic nature, the rates and mechanisms of absorption of these acids are clearly distinguishable from long chain fatty acids liposoblubles. This article gives an overview of the functionality of short chain fatty acids and their mechanisms of uptake by passive diffusion and active transport

Infant gut microbiota colonization: influence of prenatal and postnatal factors, focusing on diet

Maternal microbiota forms the first infant gut microbial inoculum, and perinatal factors (diet and use of antibiotics during pregnancy) and/or neonatal factors, like intra partum antibiotics, gestational age and mode of delivery, may influence microbial colonization. After birth, when the principal colonization occurs, the microbial diversity increases and converges toward a stable adult-like microbiota by the end of the first 3–5 years of life. However, during the early life, gut microbiota can be disrupted by other postnatal factors like mode of infant feeding, antibiotic usage, and various environmental factors generating a state of dysbiosis. Gut dysbiosis have been reported to increase the risk of necrotizing enterocolitis and some chronic diseases later in life, such as obesity, diabetes, cancer, allergies, and asthma. Therefore, understanding the impact of a correct maternal-to-infant microbial transfer and a good infant early colonization and maturation throughout life would reduce the risk of disease in early and late life. This paper reviews the published evidence on early-life gut microbiota development, as well as the different factors influencing its evolution before, at, and after birth, focusing on diet and nutrition during pregnancy and in the first months of life

Experiencia inter-universitaria de prácticas en Sistemas Abiertos

Este artículo describe una experiencia de prácticas conjuntas de alumnos de las universidades Rovira i Virgili, de Murcia, y Católica de San Antonio de Murcia, denominada OSDC (Open Systems Development Contest) [1]. Las prácticas consisten en el desarrollo de sistemas distribuidos basados en la tecnología Web. La coordinación de los alumnos se realiza por medio de herramientas de apoyo al trabajo colaborativo, principalmente BSCW. Los alumnos diseñan e implementan sistemas de información que emplean tecnologías abiertas, como XML, servlets y JSP. Los resultados demuestran que este tipo de experiencias favorecen el aprendizaje, no sólo de herramientas de desarrollo de software, sino también de aptitudes de gran utilidad en el trabajo en grupo

Predation impact on threatened spur-thighed tortoises by golden eagles when main prey is scarce

A reduction in adult survival in long-living species may compromise population growth rates. The spur-thighed tortoise (Testudo graeca) is a long-lived reptile that is threatened by habitat loss and fragmentation. Golden eagles (Aquila chrysaetos), whose breeding habitats overlap that of tortoises, may predate them by dropping them onto rocks and breaking their carapaces. In SE Spain, the number of golden eagles has increased in the last decades and the abundance of their main prey (i.e., rabbits Oryctolagus cuniculus) has decreased. Our aims were to 1) describe the role of tortoises in golden eagles’ diet, and 2) estimate the predation impact of golden eagles on tortoises in eagles’ territories and in the regional tortoise population. We collected regurgitated pellets and prey remains under eagle nests and roosts, and obtained information on tortoise abundance and population structure and rabbit abundance. We found that tortoises were an alternative prey to rabbits, so that eagles shifted to the former where the latter were scarce. The average predation rate on tortoises was very low at the two studied scales. However, eagles showed a marked selection for adult female tortoises, which led the tortoise sex ratio to be biased towards males in those eagle territories with higher tortoise predation. Whether this may compromise the spur-thighed tortoise long-term population viability locally deserves further attention.Much information on the spur-thighed tortoise populations and the regional abundance model was obtained with Projects CGL2012-33536 and CGL2015-64144 funded by the Spanish Ministry of Science and the European Regional Development Fund, Grant PID2019-105682RA-I00, funded by MCIN/AEI/10.13039/501100011033 and AICO/2021/145 funded by the Regional Valencian Government. MM was supported by a Ramón y Cajal research contract from MINECO (RYC-2015-19231), MCM by a pre-doctoral grant of the Spanish Ministry of Science (FPU1700633), and RCRC by a postdoctoral grant funded by the Regional Valencian Government (APOSTD/2020/090) and by the European Union-Next Generation EU in the Maria Zambrano Program (ZAMBRANO 21-26). The Dirección General de Gestión del Medio Natural of Andalusian Government (SGB/FOA/AFR) and the Dirección General de Medio Natural of the Murcia Region authorised and facilitated the sampling of golden eagle territories (AUF20140061) and the spur-thighed tortoise populations (SGYB/AF/DBP, SGYB/AFR/DBP, AUF20160056, AUF20140057)

Ancient mitogenomics clarifies radiation of extinct Mascarene giant tortoises ( Cylindraspis spp.)

The five extinct giant tortoises of the genus Cylindraspis belong to the most iconic species of the enigmatic fauna of the Mascarene Islands that went largely extinct after the discovery of the islands. To resolve the phylogeny and biogeography of Cylindraspis, we analysed a data set of 45 mitogenomes that includes all lineages of extant tortoises and eight near-complete sequences of all Mascarene species extracted from historic and subfossil material. Cylindraspis is an ancient lineage that diverged as early as the late Eocene. Diversification of Cylindraspis commenced in the mid-Oligocene, long before the formation of the Mascarene Islands. This rejects any notion suggesting that the group either arrived from nearby or distant continents over the course of the last millions of years or had even been translocated to the islands by humans. Instead, Cylindraspis likely originated on now submerged islands of the Réunion Hotspot and utilized these to island hop to reach the Mascarenes. The final diversification took place both before and after the arrival on the Mascarenes. With Cylindraspis a deeply divergent clade of tortoises became extinct that evolved long before the dodo or the Rodrigues solitaire, two other charismatic species of the lost Mascarene fauna

Conclusiones y propuestas de manejo de las poblaciones y especies de anfibios y reptiles alóctonos en España

El criterio fundamental para considerar que una especie es alóctona en el territorio español se basa en la constatación de que la colonización no ha sido natural, sino de origen antrópico.Peer Reviewe

Euclid preparation: XVI. Exploring the ultra-low surface brightness Universe with Euclid/VIS

Context While Euclid is an ESA mission specifically designed to investigate the nature of dark energy and dark matter, the planned unprecedented combination of survey area (∼15 000 deg2), spatial resolution, low sky-background, and depth also make Euclid an excellent space observatory for the study of the low surface brightness Universe. Scientific exploitation of the extended low surface brightness structures requires dedicated calibration procedures that are yet to be tested. Aims We investigate the capabilities of Euclid to detect extended low surface brightness structure by identifying and quantifying sky-background sources and stray-light contamination. We test the feasibility of generating sky flat-fields to reduce large-scale residual gradients in order to reveal the extended emission of galaxies observed in the Euclid survey. Methods We simulated a realistic set of Euclid/VIS observations, taking into account both instrumental and astronomical sources of contamination, including cosmic rays, stray-light, zodiacal light, interstellar medium, and the cosmic infrared background, while simulating the effects of background sources in the field of view. Results We demonstrate that a combination of calibration lamps, sky flats, and self-calibration would enable recovery of emission at a limiting surface brightness magnitude of μlim = 29.5-0.2+0.08 mag arcsec-2 (3σ, 10 × 10 arcsec2) in the Wide Survey, and it would reach regions deeper by 2 mag in the Deep Surveys. Conclusions Euclid/VIS has the potential to be an excellent low surface brightness observatory. Covering the gap between pixel-To-pixel calibration lamp flats and self-calibration observations for large scales, the application of sky flat-fielding will enhance the sensitivity of the VIS detector at scales larger than 1″, up to the size of the field of view, enabling Euclid to detect extended surface brightness structures below μlim = 31 mag arcsec-2 and beyond

COMPARACIÓN ENTRE LUBINA (DICENTRARCHUS LABRAX) SALVAJE Y CULTIVADA: COMPOSICIÓN QUÍMICA Y VARIACIÓN DEL CONTENIDO EN ÁCIDOS GRASOS TRAS EL COCINADO

Sea bass (Dicentrarchus labrax) has a high commercial value, and has been widely farmed in the last ten years. Consumers consider that wild sea bass presents a high quality, so that the first objective of the present study has been to compare the chemical composition of the flesh from wild and farmed sea bass. In addition, from a nutritional point of view, fish meat is considered an important dietary source of protein and long chain ω-3 polyunsaturated fatty acids, mainly eicosapentaenoic acid (EPA, C20:5 ω-3) and docosahexaenoic acid (DHA, C22:6 ω-3), because of that the second objective of our work has been to ascertain the fatty acid profile in the flesh of wild and farmed sea bass and to evaluate the changes in these nutrients during steam cooking. 10 specimens of each origin (wild and farmed) of sea bass with an average size of 350g, were selected to determine the proximate composition (protein, fat, moisture and ash), mineral content, total basic volatile nitrogen, muscle pH, and hydroxyproline and collagen concentrations. The fatty acids were determined in the flesh of raw and steam cooked fillets of both types of sea bass using gas chromatography. The obtained results showed statistical differences in those parameters related to environmental and nutritional conditions (total fat and mineral content). The profile of fatty acids showed statistical differences due to type of cultivar since the flesh of farmed sea bass presented the highest content of linoleic acid (the main ω-6). No changes in the fatty acids of wild sea bass flesh after steam coking were observed, however, the flesh of farmed specimens showed significant losses of monounsaturated fatty acids (oleic acid) from the ventral fat probably from adipose tissue located beneath the skin.La lubina (Dicentrarchus labrax) es una especie de elevado valor comercial, cuyo cultivo ha experimentado un considerable incremento en los últimos años. Debido a que el consumidor considera que el producto procedente de la pesca extractiva es de mayor calidad, el primer objetivo planteado en el presente estudio ha sido comparar la composición nutricional de la lubina procedente de pesca extractiva (salvaje) con la de la lubina procedente de la acuicultura (cultivada). Ya que, desde un punto de vista nutricional, el pescado es un importante fuente de proteínas y de ácidos grasos poliinsaturados de cadena larga ω-3, especialmente ácido eicosapentanoico (EPA, C20:5 ω-3) y docosahexanoico (DHA, C22:6 ω-3), el segundo objetivo ha sido estudiar las diferencias en el perfil de ácidos grasos de lubinas de ambas procedencias, y evaluar el efecto del cocinado sobre el mismo. Se seleccionaron 10 especimenes de cada tipo de lubina, con un peso medio de 350 g, para la determinación de la composición química proximal (proteínas, grasa, humedad y cenizas), el contenido de minerales, el nitrógeno básico volátil total, el pH muscular y el contenido de hidroxiprolina y colágeno. El perfil de ácidos grasos se analizó en la carne de lubina cruda y cocinada al vapor, mediante cromatografía gaseosa. Los resultados obtenidos mostraron diferencias estadísticamente significativas en aquellos parámetros que dependen directamente de la alimentación y el medio ambiente (grasa total y minerales). En cuanto al perfil de ácidos grasos se observaron diferencias en el contenido de ácido linoléico (principal ω-6), mostrando la lubina cultivada una concentración significativamente superior. Aunque no encontramos cambios en el perfil de ácidos grasos de la carne de la lubina salvaje después del cocinado al vapor durante cinco minutos, en la lubina cultivada si se observaron diferencias significativas, como consecuencia de la pérdida de ácidos grasos monoinsaturados en la grasa ventral durante la cocción