Adaptation of digestive enzymes to dietary protein, carbohydrate and fibre levels and influence of protein and carbohydrate quality in Penaeus vannamei larvae (Crustacea, Deecapoda) / Le Moullac, Gilles

Public ISBD Faire une suggestion d'achat Titre : Adaptation of digestive enzymes to dietary protein, carbohydrate and fibre levels and influence of protein and carbohydrate quality in Penaeus vannamei larvae (Crustacea, Deecapoda) Type de document : texte imprimé Auteurs : Le Moullac, Gilles, Auteur Importance : pp. 203-210 Langues : Anglais (eng) Index. décimale : 578 Histoire naturelle des organismes vivants Résumé : Activity of digestive enzymes (trypsin, chymotrypsin and amylase) was studied in relation with food in Penaeus vannamei larvae first stages. Microparticles containing casein involved the decrease of soluble protein content and enzyme activities. Specific trypsin activity but not chymotrypsin was correlated (p<2%) to casein level between 10 and 60% in microparticles. Cellulose fibres in food seemed to have little effect on digestive enzymes. Starch, between 1 and 20% in microparticles, had no influence on specific amylase activity. The effect of different feeding conditions were also tested on growth. No clear relationship between growth and enzyme is established since only trypsin is concerned in the case of a casein dose effect in the food. The protein source (casein, gelatin, squid meal or fish protein soluble concentrate) as well as the carbohydrate quality (soluble starch, standard corn starch, amylopectin corn starch or pregelatinized com starch) were tested. Squid meal stimulated significantly chymotrypsin activity (p<2%) while trypsin activity decreased with fish protein soluble concentrate (p<5%). Source of carbohydrate seemed very important, amylase activity increased significantly (p<2%) with com starch. These adaptations are not correlated to growth performances since squid meal or fish protein soluble concentrate improved larval development until zoe 3 substage. These results suggest a specific induction of digestive enzymes to the food quality in larvae independent of growth performances. Adaptation of digestive enzymes to dietary protein, carbohydrate and fibre levels and influence of protein and carbohydrate quality in Penaeus vannamei larvae (Crustacea, Deecapoda) [texte imprimé] / Le Moullac, Gilles, Auteur . - [s.d.] . - pp. 203-210. Langues : Anglais (eng) Index. décimale : 578 Histoire naturelle des organismes vivants Résumé : Activity of digestive enzymes (trypsin, chymotrypsin and amylase) was studied in relation with food in Penaeus vannamei larvae first stages. Microparticles containing casein involved the decrease of soluble protein content and enzyme activities. Specific trypsin activity but not chymotrypsin was correlated (p<2%) to casein level between 10 and 60% in microparticles. Cellulose fibres in food seemed to have little effect on digestive enzymes. Starch, between 1 and 20% in microparticles, had no influence on specific amylase activity. The effect of different feeding conditions were also tested on growth. No clear relationship between growth and enzyme is established since only trypsin is concerned in the case of a casein dose effect in the food. The protein source (casein, gelatin, squid meal or fish protein soluble concentrate) as well as the carbohydrate quality (soluble starch, standard corn starch, amylopectin corn starch or pregelatinized com starch) were tested. Squid meal stimulated significantly chymotrypsin activity (p<2%) while trypsin activity decreased with fish protein soluble concentrate (p<5%). Source of carbohydrate seemed very important, amylase activity increased significantly (p<2%) with com starch. These adaptations are not correlated to growth performances since squid meal or fish protein soluble concentrate improved larval development until zoe 3 substage. These results suggest a specific induction of digestive enzymes to the food quality in larvae independent of growth performances.

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Effect of sediment nearness on the metabolic enzyme activity and energy state of the oyster Crassostrea gigas / Le Moullac, Gilles

Public ISBD Faire une suggestion d'achat Titre : Effect of sediment nearness on the metabolic enzyme activity and energy state of the oyster Crassostrea gigas Type de document : texte imprimé Auteurs : Le Moullac, Gilles, Auteur Importance : pp. 279-286 Langues : Anglais (eng) Index. décimale : 578 Histoire naturelle des organismes vivants Résumé : This study was designed to assess in situ the effects of sediment nearness on Crassoslrea gigas metabolism. One year-old oysters were reared for 5 months (April-August) in plastic bags on metallic frames at 10 and 60 cm off the sediment at the beginning of April. The management of the energetic resources (storage, consumption) was estimated with respect to biochemical changes of proteins, lipids and carbohydrates. In order to evaluate the effect of the sediment nearness at cellular level, the metabolic rate was evaluated by assessing pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK) enzyme activities and electron transport system (ETS) activity. The metabolic pathways were assessed by measuring ATP and intermediary metabolites such as alanine, succinate and aspartate. Despite similar survival and growth at the two rearing levels, the protein, lipid and carbohydrate content were significantly lower in the oysters close to the bottom. In the oysters reared at 10 cm, PK activity was also significantly reduced and a significant negative correlation between alanine content and PK activity was revealed. The sediment nearness decreased significantly the ATP content in the oyster. There was a significant relationship between ATP and aspartate in these oysters. The use of aspartate contributed to complete the metabolic pathways along with carbohydrate allowing to maintain the same biological performance as the oyster reared far from the bottom. The energy state (proteins, lipids, carbohydrates and ATP contents) could suggest that the oysters close to the sediment were fed less but the metabolic enzyme activities allow to suggest an oxygen deficiency. However, the reduced PK activity, the absence of PEPCK activity stimulation and the utilization of aspartate suggest a transition stage to anaerobiosis. Effect of sediment nearness on the metabolic enzyme activity and energy state of the oyster Crassostrea gigas [texte imprimé] / Le Moullac, Gilles, Auteur . - [s.d.] . - pp. 279-286. Langues : Anglais (eng) Index. décimale : 578 Histoire naturelle des organismes vivants Résumé : This study was designed to assess in situ the effects of sediment nearness on Crassoslrea gigas metabolism. One year-old oysters were reared for 5 months (April-August) in plastic bags on metallic frames at 10 and 60 cm off the sediment at the beginning of April. The management of the energetic resources (storage, consumption) was estimated with respect to biochemical changes of proteins, lipids and carbohydrates. In order to evaluate the effect of the sediment nearness at cellular level, the metabolic rate was evaluated by assessing pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK) enzyme activities and electron transport system (ETS) activity. The metabolic pathways were assessed by measuring ATP and intermediary metabolites such as alanine, succinate and aspartate. Despite similar survival and growth at the two rearing levels, the protein, lipid and carbohydrate content were significantly lower in the oysters close to the bottom. In the oysters reared at 10 cm, PK activity was also significantly reduced and a significant negative correlation between alanine content and PK activity was revealed. The sediment nearness decreased significantly the ATP content in the oyster. There was a significant relationship between ATP and aspartate in these oysters. The use of aspartate contributed to complete the metabolic pathways along with carbohydrate allowing to maintain the same biological performance as the oyster reared far from the bottom. The energy state (proteins, lipids, carbohydrates and ATP contents) could suggest that the oysters close to the sediment were fed less but the metabolic enzyme activities allow to suggest an oxygen deficiency. However, the reduced PK activity, the absence of PEPCK activity stimulation and the utilization of aspartate suggest a transition stage to anaerobiosis.

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Modélisation de la résistance aux chocs de salinité des postlarvesde Penaeus vannamei / Le Moullac, Gilles

Public ISBD Faire une suggestion d'achat Titre : Modélisation de la résistance aux chocs de salinité des postlarvesde Penaeus vannamei Type de document : texte imprimé Auteurs : Le Moullac, Gilles, Auteur Importance : pp. 169-173 Langues : Français (fre) Index. décimale : 578 Histoire naturelle des organismes vivants Résumé : La notion de qualité des postlarves de crevettes pénéides, qui sous-entend un potentiel de survie, est un paramètre resté longtemps subjectif. Les critères zootechniques et les observations visuelles ne sont pas des paramètres suffisants pour apprécier la condition physiologique des postlarves à la sortie de l'écloserie. La résistance aux chocs de salinité est un critère représentatif de l'état des postlarves. Cette étude a pour but de présenter un modèle de régression non linéaire à deux variables (taille, salinité) de la résistance des postlarves Penaeus vannamei à des chocs de salinité. Entre le T et le 20e jour après la métamorphose 5 chocs de salinité (20, 15, 10, 5 et 2°/00) sont testés chaque jour, avec respectivement 50 postlarves par salinité. Le taux de survie est enregistré après 2 heures. Parallèlement, la croissance des postlarves en élevage est étudiée par la mesure quotidienne de 30 animaux. La tolérance à la salinité des postlarves P. vannamei augmente avec la taille qui s'accroît d'une façon linéaire. Modélisation de la résistance aux chocs de salinité des postlarvesde Penaeus vannamei [texte imprimé] / Le Moullac, Gilles, Auteur . - [s.d.] . - pp. 169-173. Langues : Français (fre) Index. décimale : 578 Histoire naturelle des organismes vivants Résumé : La notion de qualité des postlarves de crevettes pénéides, qui sous-entend un potentiel de survie, est un paramètre resté longtemps subjectif. Les critères zootechniques et les observations visuelles ne sont pas des paramètres suffisants pour apprécier la condition physiologique des postlarves à la sortie de l'écloserie. La résistance aux chocs de salinité est un critère représentatif de l'état des postlarves. Cette étude a pour but de présenter un modèle de régression non linéaire à deux variables (taille, salinité) de la résistance des postlarves Penaeus vannamei à des chocs de salinité. Entre le T et le 20e jour après la métamorphose 5 chocs de salinité (20, 15, 10, 5 et 2°/00) sont testés chaque jour, avec respectivement 50 postlarves par salinité. Le taux de survie est enregistré après 2 heures. Parallèlement, la croissance des postlarves en élevage est étudiée par la mesure quotidienne de 30 animaux. La tolérance à la salinité des postlarves P. vannamei augmente avec la taille qui s'accroît d'une façon linéaire.

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