Digestive enzymes in marine species. II. Amylase activities in gut from seabream (Sparus aurata), turbot (Scophthalmus maximus) and redfish (Sebastes mentella)

8 páginas, 3 tablas, 3 figurasThe amylase activity of the digestive tract of three carnivorous fish species (Spurus aurata, ScophtMmw maximus and Sebustes me&la) has been studied. The activity of seabream and turbot showed its maximum at neutral pH (7.0-7.5); meanwhile, the activity of redfish had an optimum pH at 4.5-5.0. The to function ranged between 35 and 45°C for the three species. The Arrhenius plots of the intestinal activities of seabream and turbot showed breakpoints at temperatures close to those of their physiological activities. High saline concentrations inhibited the activity of seabream and turbot and activated the activity of redfish. Seabream activity was absolutely dependent on calcium ions. On the contrary, redfish activity was only detected in the absence of this metal. Studies carried out by using several effecters suggested that the activities found in these three species are different. Considering our results from a point of view of the environmental conditions of these species, it might be concluded that enzymatic digestion of dietary carbohydrates proceeds at very low rate. Physiologicat implications are discussedThis work was supported b a grant from the Xunta de Galicia XUGA40201 B90.Peer reviewe

Biochemical studies in marine species - II. NADP+-dependent isocitrate dehydrogenase from turbot (Scophthalmus maximum L.) larvae

8 páginas, 4 tablas, 7 figurasThe isocitrate dehydrogenase activity specific for NADP + has been studied in early turbot larvae and compared with that of their adult counterparts. The activity showed a broad optimum pH between 7.9 and 9.0, and an optimum temperature of 400C (with an E, of 23.3 k J/tool) and was inhibited by high ionic strength and heavy metals. The apparent K, values for the substrates were 16.7 pM for isocitrate, 3.5 for NADP +, 29.6 pM for Mk~ + and 3.3/JM for the Mg-isocitrate complex. The effect of the absence of Mk~ + on the enzyme affinity for its substrates is also reported. The enzyme stability was decreased by iodoacetic acid and this effect reverted by isocitrate. The enzyme activity was inhibited by metabolites such as citrate, oxoglutarate and adenine dinucleotides. It was also fully inhibited by the concerted action of glyoxylate and oxaloacetate.This work has been supported by a grant from the Xunta de Galicia No. XUGA40201B90.Peer reviewe

Digestive enzymes in marine species. I. Proteinase activities in gut from redfish (Sebastes mentella), seabream (Sparus aurata) and turbot (Scophthalmus maximus)

8 páginas, 3 tablas, 5 figurasThe proteolytic activities of the digestive tract of three carnivorous fish species (Sebastes mentella, Scophthalmus maximus, Sparus aurata) have been studied. The activity found in the stomach showed a pH optimum of 2.0 for all species, whereas this was in the alkaline range (9.5-10.0) in the intestinal extracts. Similar optimal temperature was measured for all species, although higher residual activities were detected at low temperatures in redfish and turbot. Lower E a values were detected in stomach than in intestine. The effect of NaC1 concentration on protein digestion differed between stomach and intestine being inhibitory in the former. The main proteolytic enzyme for the acid activity of the stomach of the three species seemed to be a pepsin. However, the enzymatic composition of the intestine was more species specificThis work was supported by a grant from the Xunta de Galicia No. XUGA402OIB90.Peer reviewe

Aislamiento de hidrogenasas bacterianas: estudio de sus propiedades Redox

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. Fecha de lectura: 23-09-198

Use of antibiotics to improve the larval rearing of turbot for experimental purposes

Actas del V Congreso Nacional de Acuicultura, Sant Carles de la Ràpita, 10-13 Mayo 1995[EN] This paper focuses on the description of a technique for the early rearing of turbot (Scophthalmus maximus L.) larvae. The rearing method is based on the use of antibiotics with both live prey and larvae, lealing to acceptable improvements in the rearing performances (survival, growth). It is particularly useful in experiments requiring a high suppply of larvae. On the contrary, its applicability for industrial puposes is not recommended. Some physiological and feeding aspects of the larvae are also considered[ES] En este trabajo se describe una técnica de cultivo de larvas de rodaballo (Scophthalmus maximus L.), basada en el uso de antibióticos, con la que se obtienen unos rendimientos aceptables (supervivencia, crecimiento) en la fase de alimentación con presas vivas. La técnica utiliza tratamientos antibacterianos tanto en presas vivas como en el medio de cultivo larvario,sin afectar a sus características bioquímicas. La técnica no es de aplicación industrial sino que es aplicable particularmente a situaciones experimentales en las que se necesita disponer de un aporte elevado de larvas. En el trabajo también se consideran aspectos fisiológicos y alimentarios de las larvasProyecto AGF 185/92 (CICYT)N

Partial purification and biochemical characterization of TMAOase from kidney of European hake (Merluccius merluccius)

7 páginas, 6 figuras, 1 tablaThe trimethylamine N-oxide aldolase (TMAOase) activity from kidney of European hake (Merluccius merluccius) was characterized by using chromatographic and electrophoretic techniques. Soluble TMAOase was obtained using a differential centrifugation protocol with CHAPS and NaCl buffer. Two TMAOase fractions were isolated by ion exchange chromatography using a FPLC system. For this purpose the weak anion exchanger ANX Sepharose 4 Fast Flow (high sub), suited for high molecular mass proteins, was employed. After anion exchange chromatography, fractions were separated by native electrophoresis. One of the fractions eluted at 0.45 M sodium chloride concentration, and had a charge/ mass ratio in electrophoresis similar to bovine serum albumin, with a molecular weight of approximately 100 kDa. The second fraction eluted at 0.7 M sodium chloride concentration, and presented a very low electrophoretic mobility due to either a low charge/mass ratio or due to the presence of protein aggregates of different sizes of between 440 and 2,000 kDa. Proteins present in both TMAOase fractions showed acid isoelectric points of between 4.55 and 5.85.The authors wish to thank the European Commission for financially supporting the Research Projects FAIRCT95– 1111 and AIR 3-CT94–1921. Author Rey-Mansilla acknowledges Caixanova for granting a research fellowship.Peer reviewe

Influence of enrichment diets on the nutritional quality of Brachionus plicatilis and Artemia sp.

6 pages, 3 tables.-- Actas del II Congreso Nacional de Acuicultura, Santiago de Compostela, 1-4 Diciembre 1987[EN] The nutritional quality of Brachionus plicatilis and Artemia sp. is studied in relation to the chemical composition and fatty acids distribution of different enrichment diets (Isochysis galbana, Topal and Selco). The lipids composition of rotifer depends on the total lipids composition of the total lipids composition of the enrichment diets. The levels of PUFA W3 in the diets, as well as the time of enrichment, also infuence the level pf PUFA W3 in the rotifer. No substantial change was observed in Artemia[ES] Se estudia la incidencia de la composición química y dsitribución de ácidos grasos de distintas dietas enriquecedoras (Isochrysis galbana, Topal y Selco), sobre la calidad nutritiva de Brachionus plicatilis y Artemia sp. De modo general se observa que la composición lipídica del rotífero de la proporción de lípidos totales de los enriquecedores. Los valores que presentan los enriquecedores, en relación al nivel de PUFA W3, también tiene influencia sobre los niveles de PUFA W3 del rotífero, aumentando además la proporción de PUFA W3 con el tiempo de enriquecido. En la Artemia no se observa ningún cambio sustancialN

Enriquecimiento en ácido ascórbico del rotífero Brachionus plicatilis O.F. Müller para el cultivo de larvas de peces marinos

Actas del V Congreso Nacional de Acuicultura, Sant Carles de la Ràpita, 10-13 Mayo 1995[EN] The aim of this work was to establish a laboratory tool to permit rapid progress towards quantification of the requirement for ascorbic acid (AA) in marine fish larvae during the early feeding period. As a first step rotifers only differing in their AA levels were successfully produced. The biochemical and enzymatic composition of this organism remained stable in clear seawater for, at least, 24 hours. Therefore they were considered suitable for increasing A levels in turbot larvae. The AA level of the larvae was positively correlated with the AA content of the rotifer used. This demonstrates that AA was successfully incorporated in the larvae[ES] El objetivo de este trabajo fue desarrollar una técnica que permitiera estudiar el requerimiento de ácido ascórbico (AA) en larvas de peces marinos durante las fases iniciales de alimentación. En primer lugar, se desarrolló una técnica de enriquecimiento de rotíferos que permitió obtener distintos niveles de AA en la presa, sin observarse cambios en su composición bioquímica ni en su equipamiento enzimático 24 horas después de ser transferidos a agua limpia. Por tanto, la utilidad de la técnica utilizada se consideró satisfactoria. La utilización de estos rotíferos con larvas de rodaballo puso en evidencia una incorporación eficiente de la vitamina en las larvas, ya que el nivel de AA en estas estuvo directamente relacionado con el nivel de la vitamina en las presasEuropean Community, project no. AIR2-CT93-1449 (DG IX SSMA)N

Effect of environmental factors on lipid digestion during early turbot (Scophthalmus maximus) larvae development

International workshop Development and aquaculture of marine larvae, Bergen, Norway, August 12-15, 1990N

Chemical changes during development in turbot (Scophthalmus maximus) eggs and larvae

International workshop Development and aquaculture of marine larvae, Bergen, Norway, August 12-15, 1990N