Comparison of brown trout (

Brown trout and rainbow trout (average weight 100 g) were reared in fresh water at 12 °C under the same conditions before transferring brown trout to sea water, in order to compare phosphorus utilisation in both species. Apparent phosphorus availability, orthophosphate excretion and phosphorus accretion in the fish were directly determined. Thus, actual phosphorus mass balance was built. Rainbow trout raised in fresh water had a higher phosphorus retention coefficient (maximum 50 %) than brown trout reared in fresh water (maximum 45 %). Transferring brown trout to sea water induced a reduction in phosphorus retention (maximum 39 %). Orthophosphate excretion, ranging 7-20 mg phosphorus per kg wet weight per day, represented 10-20 % of ingested phosphorus. Phosphorus availability was lower in brown trout raised in sea water (65 %) than brown trout raised in fresh water (76 %). Phosphorus balance measurements showed that 90 to 98 % of phosphorus flow could be accounted for

Influence of dietary bulk agents (silica, cellulose and a natural zeolite) on protein digestibility, growth, feed intake and feed transit time in European seabass (

The incorporation of various bulk agents by substitution of an equivalent amount of the basal mixture was studied in terms of protein digestibility, growth performance and body composition in European seabass (Dicentrarchus labrax) juveniles. During the growth trial, triplicate groups of 40 seabass (mean initial weight: 7.0 g) were grown in seawater (salinity: 35; temperature: 18 °C) over 60 days. Fish were hand-fed, three times a day, one of seven experimental diets. Bulk agents tested at 10 or 20 % level of incorporation were silica, cellulose and a natural zeolite (chabamin). Feeding rates were adjusted in proportion to the percent dilution of the control diet without bulk incorporation. The incorporation of the bulk agents, at a 10 and 20 % level, did not affect protein digestibility or growth performance. Dietary bulk incorporation reduced feed efficiency values, particularly at the 20 % incorporation level. However, this reduction was mostly caused by the dietary nutrient dilution of the bulk-incorporated diets, rather than by a negative effect of the bulk agents as dietary ingredients. In comparison to the control treatment, bulk incorporation at 10 and 20 % level did not affect protein retention values. When compared with the control diet, 20 % bulk agent incorporation changed the evacuation profile of faeces and increased faecal egestion time

Remplacement des herbivores proies par des microparticules inertes ; une application à l'élevage larvaire de Penaeus japonicus

The present work describes the recoring of Pengeus japonicus larvae using only unicellular algae and inert microparticles. The use of these particles is compared with that of living animal preys, more frequently employed.Le présent travail a pour objet la description d'une technique d'élevage des larves de Penaeus japonicus ne faisant intervenir que des algues unicellulaires et des mioropartioules inertes. L'utilisation de ces dernières est comparée avec celle des proies animales vivantes, plue classiquement employées

Comparison of brown trout (Salmo trutta) reared in fresh water and sea water to freshwater rainbow trout (Oncorhynchus mykiss) .1. Growth and nitrogen balance

Brown trout and rainbow trout (average weight 100 g) were reared in fresh water at 12 degrees C under the same conditions before transfer of brown trout to sea water, in order to compare nitrogen utilisation in the two species. Apparent protein digestibility (ADC), nitrogen (ammonia and urea) excretion, protein productive value (PPV) and actual observed nitro en mass balance were determined. Rainbow trout raised in fresh water had a higher growth rate (1.1 vs 0.8%. d(-1)), better food conversion ratio (0.7 vs 1.0), better ADC (91 vs 85%) and PPV (45 vs 35%) and lower ammonia excretion rates than brown trout reared in fresh water. Transferring brown trout to sea water induced lower PPV (30%) and ammonia and urea excretion. Salinity did not modify metabolic efficiency in brown trout. Fat content was higher in brown trout (7.7-8.9% ww) than in rainbow trout (5.7-7.6% ww). Nitrogen mass balance indicated that compounds other than ammonia and urea were produced in higher quantities by seawater brown trout. Behaviour, less domestication and specific ability to utilise protein could explain the differences between the two species.Des truites communes (fario) et des truites arc-en-ciel de 100 g de poids moyen ont été élevées à 12 °C dans des conditions strictement identiques, avant le transfert des truites communes en eau de mer, dans le but de comparer l'utilisation de l'azote chez les deux espèces. La digestibilité apparente des protéines (ADC), l'excrétion ammoniacale et uréique, et l'accrétion protéique (PPV) des poissons ont été estimées. Les bilans de masse ont été construits avec ces données. Les truites arc-en-ciel élevées en eau douce ont présenté un meilleur taux de croissance (1.1 vs 08 %.j−1), un meilleur coefficient de transformation de l'aliment (0.7 vs 1.0), de meilleurs ADC (91 vs 85 %) et PPV (45 vs 35 %), ainsi qu'une excrétion ammoniacale plus faible que les truites communes élevées en eau douce. Après transfert en mer, l'excrétion ammoniacale et l'excrétion uréique ont diminué chez la truite commune, ainsi que la rétention protéique (30 %). La salinité n'a pas modifié l'efficacité métabolique de la truite commune. Le contenu lipidique de la truite commune (7.7-8.9 % poids frais) était plus élevé que celui de la truite arc-en-ciel (5.7-7.6 % poids frais). Le bilan de masse de l'azote a indiqué que les autres molécules que l'ammoniaque et l'urée étaient excrétées en plus grandes quantités par la truite commune en eau de mer. Le comportement, une domestication moins avancée et une capacité distincte d'utilisation des protéines pourraient expliquer les différences entre les deux espèces

Accoutumance de jeunes soles (Solea solea) à différents aliments inertes après achèvement de la métamorphose

A comparative test of various inert diets was performed on 9 batches of 150 one month old soles, wheighing an average 42 mg, and feeding on live brine shrimps. It lasted for 2 months, in 60 l square tanks, with sand bottoms. . A succession of frozen natural feed, ending with the Bivalve Laevioardium arassum, was compared to 2 different artificial diets, offered as dry pellets. The inurement to the pellets was facilitated by an incorporation of various meals, used as flavourings, during a 6 weeks transitory period. - At the end of the experiment, the best result, 98 % survival, average weight . 1.10 g, was obtained with the natural feed. The best flavourings for dry pellets were Laevi- cardium arassum and the Polyahaete Nephthus hombergii, with 70 % survival and 0.99 g for the first one, 52 % survival and 1.10 g for the second one. The possible reproduction of these results on a large scale is not yet demonstratedUne expérience d'accoutumance à divers aliments inertes est effectuée sur une _ série de 9 lots de 150 soles âgées de 1 mois, pesant en moyenne 42 mg, habituées à se nourrir d'Artemia salirîa vivantes. Réalisée dans des bacs carrés de 60 l, à fond de sable percolé, elle dure 2 mois. Une succession d'aliments naturels congelés, qui s'achève par de la chair du mollus que bivalve Laevicardium arassum, est comparée à deux formules d'aliments composés, présentés sous forme de granulés secs. L'accoutumance à ces granulée est facilitée par l'incorporation de diverses farines naturelles- faisant fonction d'attractant, pendant une période transitoire de 6 semaines. Au terme de l'expérience, le meilleur résultat, 98 % de survie et 1,10 g de poids moyen, est fourni par les aliments naturels. Les farines de Laevicardium crassum et de l'Annélide Polyahète Nephthus hombergii se montrent les meilleurs attraatants, avec 70 % de survie et 0,99 g en moyenne pour la première, 52 % de survie et 1,10 g en moyenne pour la seconde. La possibilité d'une application de ces résultats à grande échelle n'est pas démontrée

Digestibilité des protéines et disponibilité des acides aminés de quelques matières premières chez le bar (Dicentrarchus labrax)

Protein digestibility of soyabean meal, casein-gelatin mixture and fish hydrolysate was tested in the European sea bass, using increasing substitution levels in a reference diet. The protein digestibility of the latter composed of Norwegian fish meal had already been established (91 %). An accurate estimation of the apparent digestibility coefficient was made by linear regression, for the casein-gelatin mixture and soyabean meal, but not for fish hydrolysate (non significant correlation, p > 0.05). Protein digestibility estimated by extrapolation varied with the substitution level. The estimations obtained with the highest level used for each ingredient were close to those obtained by linear regression. However they exhibited a high variability for soyabean meal and, to a lesser extent, for fish hydrolysate. The availability of individual amino acids was also investigated in each protein source. For some amino acids it was different from that of total nitrogen, suggesting that the availability of essential amino acids should be used for accurate feed formulation. Metabolic fecal nitrogen and amino acids were determined using a protein-free diet, in order to estimate true availabilities. These coefficients were not significantly different from apparent availability coefficients

Influence de divers aliments composés sur la croissance et la survie d'alevins de bars (Dicentrarchus labrax)

About twenty different prepared diets are given to young sea-basses weighing from 400 mg to a few grams, in 3 experiments, during which the growth and survival of the fish are regularly checked. The protein requirements of the species range around 47-SO % of the diet, and the energetic requirements seem to the covered by 11 to 12 % fat. The diets are mainly composed of fish meal. However fish autolysates and yeasts seem to give interesting results when incorporated into the diet.Une vingtaine d'aliments composés sont expérimentés sur de jeunes bars de 400 mg à quelques grammes, en trois séries de tests de grossissement où la croissance et la survie sont enregistrées régulièrement. Les besoins en protéines de l'espèce semblent être voisins de 47 â 50 7. du régime. La couverture énergétique paraît être assurée par un apport de 11 â 12 % de lipides. Les farines de poisson constituent la majeure partie de la ration. Cependant les autolysats de poisson et les levures apparaissent comme très intéressants à incorporer dans le régime

Augmentation of protein synthesis and degradation by poor dietary amino acid balance in european sea bass (Dicentrarchus labrax)

Sea bass fry were fed a fixed ration of one of six isonitrogenous diets differing in essential amino acid balance or physical and chemical state of the protein source (Hydrolysate vs. intact protein) to induce different growth rates. The reference diet was based on fish meal, whereas the other diets contained fish protein hydrolysate, greaves meal (i.e., defatted collagen meal) or hydrolyzed feather meal added at 30 or 50% of crude protein at the expense of Fish meal protein. Digestibility as well as fractional rate of whole-body protein synthesis was assessed. Whole-body protein synthesis was determined for each group of fish using a single injection of flooding dose of tritiated phenylalanine. Protein digestibility of the diets varied only by 5.5%. Specific growth rate and fractional protein specific growth rate, i.e., fractional protein accretion, were higher in fish fed the reference diet than in those fed the diets in which 50% of fish meal protein had been replaced by greaves or hydrolyzed feather meal protein. Compared with the reference group, whole-body protein synthesis was higher in fish fed these latter diets as well as in those fed the diet containing 30% greaves meal protein. The fractional protein accretion to fractional protein synthesis ratio, i.e., the efficiency of protein deposition, was lower in fish fed poorer dietary amino acid balance than in the reference group. The substitution of fish protein hydrolysate for intact fish protein led to a similar, though less pronounced phenomenon: nonsignificant increase in protein synthesis accompanied by significant increase in protein degradation. The increase in whole-body protein synthesis rate was linked to an increase in the amount of whole-body RNA, but the efficiency of ribosomal activity was not significantly different. Thus, decreased growth rate seemed to be a result of an increase in protein degradation

Augmentation of Protein Synthesis and Degradation by Poor Dietary Amino Acid Balance in European Sea Bass (Dicentrarchus labrax)

Sea bass fry were fed a fixed ration of one of six isonitrogenous diets differing in essential amino acid balance or physical and chemical state of the protein source (Hydrolysate vs. intact protein) to induce different growth rates. The reference diet was based on fish meal, whereas the other diets contained fish protein hydrolysate, greaves meal (i.e., defatted collagen meal) or hydrolyzed feather meal added at 30 or 50% of crude protein at the expense of Fish meal protein. Digestibility as well as fractional rate of whole-body protein synthesis was assessed. Whole-body protein synthesis was determined for each group of fish using a single injection of flooding dose of tritiated phenylalanine. Protein digestibility of the diets varied only by 5.5%. Specific growth rate and fractional protein specific growth rate, i.e., fractional protein accretion, were higher in fish fed the reference diet than in those fed the diets in which 50% of fish meal protein had been replaced by greaves or hydrolyzed feather meal protein. Compared with the reference group, whole-body protein synthesis was higher in fish fed these latter diets as well as in those fed the diet containing 30% greaves meal protein. The fractional protein accretion to fractional protein synthesis ratio, i.e., the efficiency of protein deposition, was lower in fish fed poorer dietary amino acid balance than in the reference group. The substitution of fish protein hydrolysate for intact fish protein led to a similar, though less pronounced phenomenon: nonsignificant increase in protein synthesis accompanied by significant increase in protein degradation. The increase in whole-body protein synthesis rate was linked to an increase in the amount of whole-body RNA, but the efficiency of ribosomal activity was not significantly different. Thus, decreased growth rate seemed to be a result of an increase in protein degradation

Croissance et survie du homard (Homarus vulgaris) pendant les quinze premiers stades en élevage et sous alimentation composée

Juvenile lobsters were reared for 8 months individually in separate tanks in order to obtain separate estimates of growth. Five batches were studied separately according to the type of diet : deep-frozen krill, paste, ¿try pellets and moist pellets. Growth data were collected over 15 first molt stages for each type of prepared diet. Observations deal with size and weight increments at moult and with weight/length relationships. Regression of total lengths over carapace lengths were fitted in each case.Des homards juvéniles ont été élevés pendant huit mois en logettes individuelles, permettant ainsi de suivre la croissance par individu. Les animaux ont été répartis en 5 lots, chaque. lot recevant une nourriture différente : aliment frais ou aliment composé présenté sous 4 formes différentes. L'expérience a permis de collecter des résultats originaux sur la croissance des juvéniles en élevage pendant les 15 premiers stades, la qualité de l'aliment composé spécialement défini pour cette étude. Les observations portent sur l'accroissement en taille et en poids à chaque mue, la relation taille/poids et la relation longueur totale/ longueur céphalothoracique