4 research outputs found
SIZE-REACTIVITY OF DISSOLVED ORGANIC MATTER IN THE CAPE VERDE FRONTAL ZONE
Oral communicationDissolved organic matter (DOM) plays a major role in the recycling,
export and sequestration of biogenic organic carbon, being a key
component of ocean biogeochemical cycles and of the biological and
microbial carbon pumps. Microbial degradation of DOM not only
produces CO 2 but also generates dissolved molecules of decreasing
bioavailability that can accumulate in the oceans for hundreds to
thousands of years. The size-reactivity continuum (SRC) model is the
conceptual framework to explain the DOM reactivity on a size basis,
although field tests are still scarce and some of the pieces of this
puzzle remain unclear. Taking advantage of the FLUXES-I cruise in the
Cape Verde Frontal Zone (CVFZ), we have studied the size fractionated reactivity of the high (HMW; >1 KDa) and low (LMW; <1
KDa) molecular weight fractions of the DOM from surface down to
4000 m, using a high-efficiency and low-concentration-factor
ultrafiltration cell. The wide ageing range covered by the water
masses of the CVFZ makes it an excellent site to test the SRC model.
Regarding the bulk C and N pools, the water masses with higher
oxygen utilization were more depleted in HMW molecules, with a
significant preference for the degradation of large N-containing
compounds. Accordingly, preferential degradation of HMW
fluorescent protein-like compounds was observed. In parallel,
fluorescent humic-like compounds of both HMW and LMW were
generated as by-product of the degradation of HMW organic
compounds, and the remineralization of the DOM increases the
aromaticy of both fractions, but especially the LMW one.ASL
DISSOLVED ORGANIC MATTER MOLECULAR FINGERPRINT OF THE WATER MASSES IN THE CAPE VERT FRONTAL ZONE
Oral communicationOcean water masses have been traditionally characterized by the
thermohaline and conservative chemical properties (e.g. preformed
nutrients) at their respective source regions. However, water masses
also can exhibit characteristic levels of other individual compounds or
emerging properties associated to compound classes. In this regard,
the objective of this contribution is to characterize the dissolved
organic matter (DOM) molecular fingerprint of the water masses
present in the Cape Vert Frontal Zone (CVFZ). For this purpose, a set
of 133 samples was collected from the surface to 4000 m depth in
the CVFZ during the FLUXES I cruise (12 July - 11 August 2017) and
isolated by solid-phase extraction (SPE), using styrene divinyl benzene
polymer cartridges (PPL). The molecular analysis of these SPE-PPL
extracts was performed using Fourier Transform Ion Cyclotron
Resonance Mass Spectrometry (FT-ICR MS), a method capable of
identifying thousands of molecular formulae in DOM. These analyses
have been combined with an optimum multiparameter (OMP) water
mass analysis to obtain characteristic molecular indices for the
eleven water masses present in the CVFZ, stemming from the
subtropical and subpolar North and South Atlantic as well as from the
Arctic and Antarctic Oceans. In particular, emerging properties such
as the molecular diversity (D), mean molecular mass (MW), mean C:N
ratio, aromaticity index (AI), double bond equivalent (DBE), and main
molecular groups, as well as different compounds (e.g. Lignin) and
individual heteroatoms were quantified.ASL
Estudio de la inclusión de aditivos en piensos con altas sustituciones de harina de pescado para trucha. Efecto en la salud intestinal
[EN]
Based on projected population growth over the next few decades, the aquaculture sector has become necessary in order to provide for the population's protein requirements, since most of the fishing grounds are currently overexploited. The optimization of food management and the formulation of feeds in the aquaculture sector are one of the most important solutions in order to reduce the production cost in this sector. Originally, aquaculture feed was formulated based on fishmeal and fish oils obtained from commercial fishing, which is actually a limited and unsustainable resource, from an environment as well as from an economical point of view. The objective of this study is to evaluate the growth and nutritional parameters of the rainbow trout, supplied with different feed, with a high substitution of fishmeal, for a mixture of vegetable meals, made up mainly of soybean press cake and wheat gluten. Animals in groups of 40 and with an average starting weight of 14g were used. Every feed was tested three times. The experiment lasted 78 days. The average survival rate was slightly higher than 50% due to the high temperature. The results show significantly (p <0.05) that the higher the substitution levels, the worse the results in final weight, the instantaneous growth rate, the feed conversión index and the coefficient of growth efficiency.The higher sustitution levels increase significantly the results of the viscerosomatic index and the hepatosomatic index. The results of the efficiencies retentions were lower tan the least amount of fishmeal in the feed.La acuicultura es una de las industrias de producción animal con mayor tasa de crecimiento en todo el mundo y su sostenibilidad depende en gran medida de la reducción de los costos de los piensos, por lo que es necesario buscar nuevos ingredientes para los piensos capaces de provocar un crecimiento efectivo de los peces a costos reducidos, sin afectar a la salud de los mismos.
Las sustituciones de harina de pescado por fuentes proteicas alternativas de origen vegetal y animal, se han estudiado ampliamente en los últimos años dado a que suelen ser más económicas y cuentan con una mayor disponibilidad. Las fuentes de proteína de origen vegetal han recibido la mayor atención debido a su bajo costo, alta calidad y altos rendimientos anuales, pero altas sustituciones con estas fuentes proteicas afectan el crecimiento de los peces y reducen la utilización de los nutrientes, especialmente en las especies carnívoras, además de contener compuestos antinutritivos que empeoran el aprovechamiento de los nutrientes y la salud intestinal. Esto hace que sea necesario suplementar los piensos con aditivos con el fin de aumentar la ingesta, mejorar la digestibilidad y la utilización del alimento, incrementar la ganancia en peso y evitar problemas con el sistema inmuitario.Jerusalén Lleó, E. (2017). Estudio de la inclusión de aditivos en piensos con altas sustituciones de harina de pescado para trucha. Efecto en la salud intestinal. http://hdl.handle.net/10251/89845TFG