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Feeding Experiment (feeding + experiment)

Distribution by Scientific Domains
Earth and Environmental Science50%
Life Sciences29%
Chemistry20%

Kinds of Feeding Experiment

  • day feeding experiment
    		•

    Selected Abstracts

    A Proposed Mechanism for the Reductive Ring Opening of the Cyclodiphosphate MEcPP, a Crucial Transformation in the New DXP/MEP Pathway to Isoprenoids Based on Modeling Studies and Feeding Experiments

    CHEMBIOCHEM, Issue 3 2004
    Wolfgang Brandt Dr.
    Abstract Experimental and theoretical investigations concerning the second-to-last step of the DXP/MEP pathway in isoprenoid biosynthesis in plants are reported. The proposed intrinsic or late intermediates 4-oxo-DMAPP (12) and 4-hydroxy-DMAPP (11) were synthesized in deuterium- or tritium-labeled form according to new protocols especially adapted to work without protection of the diphosphate moiety. When the labeled compounds MEcPP (7), 11, and 12 were applied to chromoplast cultures, aldehyde 12 was not incorporated. This finding is in agreement with a mechanistic and structural model of the responsible enzyme family: a three-dimensional model of the fragment L271,A375 of the enzyme GcpE of Streptomyces coelicolor including NADPH, the Fe4S4cluster, and MEcPP (7) as ligand has been developed based on homology modeling techniques. The model has been accepted by the Protein Data Bank (entry code 1OX2). Supported by this model, semiempirical PM3 calculations were performed to analyze the likely catalysis mechanism of the reductive ring opening of MEcPP (7), hydroxyl abstraction, and formation of HMBPP (8). The mechanism is characterized by a proton transfer (presumably from a conserved arginine 286) to the substrate, accompanied by a ring opening without high energy barriers, followed by the transfer of two electrons delivered from the Fe4S4cluster, and finally proton transfer from a carboxylic acid side chain to the hydroxyl group to be removed from the ligand as water. The proposed mechanism is in agreement with all known experimental findings and the arrangement of the ligand within the enzyme. Thus, a very likely mechanism for the second to last step of the DXP/MEP pathway in isoprenoid biosynthesis in plants is presented. A principally similar mechanism is also expected for the reductive dehydroxylation of HMBPP (8) to IPP (9) and DMAPP (10) in the last step. [source]

    Studies on the Biosynthesis of Bovilactone-4,4 and Related Fungal Meroterpenoids,

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2008
    Martin Lang
    Abstract The initial step in the biosynthesis of suillin (1), boviquinone-4 (2) and bovilactone-4,4 (3) in Suillus species is the geranylgeranylation of 3,4-dihydroxybenzoic acid at the 2-position. Feeding experiments with advanced precursors have identified boviquinone-4 and deacetylsuillin (9) as building blocks for the dilactone and catechol moieties, respectively, of bovilactone-4,4 (3). In order to explain the failure of boviquinone-4 (2) to incorporate side-chain-labelled deacetylsuillin (9#), an alternative sequence for the formation of 2 is proposed. During these experiments an interesting change in metabolism was noticed: after administration of larger quantities of aromatic carboxylic acids, the boviquinone-4 present in the fruit bodies disappeared and de novo synthesis of bovilactone-4,4 occurred. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

    The Biosynthesis of 3-(trans -2-Nitrocyclopropyl)alanine, a Constituent of the Signal Metabolite Hormaomycin

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 1 2005
    Melanie Brandl
    Abstract Feeding experiments with Streptomyces griseoflavus using deuterium-labeled racemic 3,3-[D2]- (6b), 4,4-[D2]- (6c), 5,5-[D2]- (6d), and 6,6-[D2]-lysine (6e), and 3-amino-5-(2-amino-1,1-dideuterioethyl)-4,5-dihydrofuran-2-one dihydrochloride (34·2HCl) were carried out in order to obtain detailed information about the hitherto unknown biosynthetic pathway from lysine to the unusual amino acid 3-(trans -2,-nitrocyclopropyl)alanine [(3-Ncp)Ala] (2), which is a building block of hormaomycin 1a. The corresponding lysine dihydrochlorides were prepared in 33, 24, 19, and 30% overall yield, respectively, along a new efficient general synthetic route applying an alkylation of the lithium enolate of O,Donnel's glycine equivalent 7 as a key step. In the attempted preparation of 5,5-[D2]-4-hydroxylysine (29), the respective ,-lactone (34·2 HCl) was obtained in five steps with 10% overall yield. The distribution of isotope labels in hormaomycins 1b,d led to the formulation of a reasonable cyclization mechanism of 2-amino-4-hydroxy-6-(hydroxyimino)hexanoic acid, an ,-oxime analogue of 4-hydroxylysine. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

    Can C4 plants contribute to aquatic food webs of subtropical streams?

    FRESHWATER BIOLOGY, Issue 6 2003
    Joanne E. Clapcott
    Summary 1. Recent stable isotope studies have revealed that C4 plants play a minor role in aquatic food webs, despite their often widespread distribution and production. We compared the breakdown of C3 (Eucalyptus) and C4 (Saccharum and Urochloa) plant litter in a small rain forest stream and used laboratory feeding experiments to determine their potential contribution to the aquatic food web. 2. All species of litter broke down at a fast rate in the stream, although Urochloa was significantly faster than Eucalyptus and Saccharum. This was consistent with the observed higher total organic nitrogen of Urochloa compared with the other two species. 3. The breakdown of Urochloa and Saccharum was, however, not associated with shredding invertebrates, which were poorly represented in leaf packs compared with the native Eucalyptus. The composition of the invertebrate fauna in packs of Urochloa quickly diverged from that of the other two species. 4. Feeding experiments using a common shredding aquatic insect Anisocentropus kirramus showed a distinct preference for Eucalyptus over both C4 species. Anisocentropus was observed to ingest C4 plant litter, particularly in the absence of other choices, and faecal material collected was clearly of C4 origin, as determined by stable isotope analysis. However, the stable carbon isotope values of the larvae did not shift away from their C3 signature in any of the feeding trials. 5. These data suggest that shredders avoid the consumption of C4 plants, in favour of native C3 species that appear to be of lower food quality (based on C : N ratios). Lower rates of consumption and lack of assimilation of C4 carbon also suggest that shredders may have a limited ability to process this material, even in the absence of alternative litter sources. Large scale clearing of forest and vegetation for C4 crops such as sugarcane will undoubtedly have important consequences for stream ecosystem function. [source]

    Evaluation of processed meat solubles as replacement for fish meal in diet for juvenile grouper Epinephelus coioides (Hamilton)

    AQUACULTURE RESEARCH, Issue 2001
    O M Millamena
    Abstract Feeding experiments were conducted to determine the efficacy of low fish-meal-based diets for juvenile grouper Epinephelus coioides (Hamilton). A diet containing 44% protein was formulated using fish meal as the major protein source. Processed meat solubles, a rendered by-product of slaughterhouses, was tested as a replacement for fish meal at increasing percentages from 0 to 100% in isonitrogenous diets. Eight dietary treatments representing fish-meal replacements were arranged in a completely randomized design with four replicates per treatment. Twenty-five fish were reared in circular fibreglass tanks of capacity 250 L, maintained in a flow-through seawater system and fed at 5,6% of total biomass, provided daily at 08:00 and 16:00 for 60 days. Results indicate that processed meat solubles can replace 40% of fish-meal protein with no adverse effects on weight gain, survival and or feed conversion ratio of E. coioides juveniles. Higher inclusion levels resulted in a significant decline in growth performance and inefficient feed conversion ratios, which may partly result from the lack of essential nutrients such as essential amino acids in meat solubles. This study has shown that the use of processed meat solubles substantially lowers the level of fish meal required in juvenile grouper diet and can be an efficient means of turning byproducts from slaughterhouses into a useful feed resource. [source]

    Biosynthesis of the Myxobacterial Antibiotic Corallopyronin A

    CHEMBIOCHEM, Issue 9 2010
    Özlem Erol
    Abstract Corallopyronin A is a myxobacterial compound with potent antibacterial activity. Feeding experiments with labelled precursors resulted in the deduction of all biosynthetic building blocks for corallopyronin A and revealed an unusual feature of this metabolite: its biosynthesis from two chains, one solely PKS-derived and the other NRPS/PKS-derived. The starter molecule is believed to be carbonic acid or its monomethyl ester. The putative corallopyronin A biosynthetic gene cluster is a trans-AT-type mixed PKS/NRPS gene cluster, containing a ,-branching cassette. Striking features of this gene cluster are a NRPS-like adenylation domain that is part of a PKS-type module and is believed to be responsible for glycine incorporation, as well as split modules with individual domains occurring on different genes. It is suggested that CorB is a trans-acting ketosynthase and it is proposed that it catalyses the Claisen condensation responsible for the interconnection of the two chains. Additionally, the stereochemistry of corallopyronin A was deduced by a combination of a modified Mosher's method and ozonolysis with subsequent chiral GC analyses. [source]

    Identification and Biosynthesis of an Aggregation Pheromone of the Storage Mite Chortoglyphus arcuatus

    CHEMBIOCHEM, Issue 11 2004
    Stefan Schulz Prof.
    Abstract In an effort to identify new pheromones from mites, the headspace of undisturbed colonies of the storage mite Chortoglyphus arcuatus was analyzed by GC-MS by use of a closed-loop stripping apparatus (CLSA) or solid-phase microextraction (SPME). The major compound emitted from the mites is (4R,6R,8R)-4,6,8-trimethyldecan-2-one (4R,6R,8R - 8). The structure was elucidated by analysis of the mass spectrum, synthesis of authentic samples, and gas chromatography on a chiral phase. Bioassays show that this compound, for which we propose the trivial name chortolure, is an aggregation pheromone for both sexes of this species. Several related compounds are released in smaller amounts by the mites. The alarm pheromones of these mites, neral and geranial, can only be found in total extracts of the mites, in which 8 occurs only in minute amounts. The method of sampling is therefore crucial for pheromone identification. Feeding experiments with deuterated propionate showed that chortolure is a polyketide, formed by successive addition of four propionate units to an acetate starter. [source]

    Soil and plant diet exposure routes and toxicokinetics of lindane in a terrestrial isopod

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2000
    José Paulo Sousa
    Abstract In most studies dealing with effects of toxic substances in saprotrophic isopods, animals are exposed to the test substance through contaminated food. Because these animals can be in a close contact with the soil surface, the substrate, as an exposure pathway, should not be neglected. Here the authors analyze the toxicokinetic behavior of lindane (,-hexachlorocyclohexane [,-HCH]) in the isopod species Porcellionides pruinosus, comparing two exposure routes: food and two soil types (artificial Organisation for Economic Cooperation and Development [OECD] soil and a natural agricultural soil). In the feeding experiment, a strong decrease of ,-HCH concentration over time was observed on the food material, with the animals showing a broader range in chemical assimilation efficiency values (averaging 17.7% and ranging from 10 to 40%). The ,-HCH bioaccumulation results indicate that when animals incubated under both soil types reached a steady state, they displayed much higher body burdens (1,359.60 pg/animal on OECD soil and 1,085.30 pg/animal on natural soil) than those exposed to contaminated food (43.75 pg/animal). Kinetic models also revealed much lower assimilation and elimination rates in the food experiment (20.66 pg/d and 0.10 pg/d) than in both soil experiments (238.60 pg/d and 350.54 pg/d for the assimilation rate and 0.19 pg/d and 0.32 pg/d for the elimination rate). Differences in results between exposure routes are discussed according to equilibrium-partitioning theory and the enhanced relevance of the substrate exposure route is analyzed under future prospects on chemical toxicity testing using isopods. [source]

    Studies of the Biogenesis of Verrucosins, Toxic Diterpenoid Glycerides of the Mediterranean Mollusc Doris verrucosa

    EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2003
    Angelo Fontana
    Abstract The biogenesis of verrucosins, diterpenoid glycerides of the marine mollusc Doris verrucosa, has been investigated by feeding experiments with labelled precursors. Incorporation of radioactive D -[U- 14C]-glucose into the diterpenes proved the de novo origin of verrucosins in the mollusc. Biogenesis of glycerol and terpenoid substructures has been investigated by feeding experiment with 13C-labelled precursors. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Effect of experimentally altered food abundance on fat reserves of wintering birds

    JOURNAL OF ANIMAL ECOLOGY, Issue 5 2003
    Christopher M. Rogers
    Summary 1Current models of adaptive fat regulation make opposing predictions concerning the effect of increased winter food supply on size of the avian winter fat reserve. To distinguish between models, food supply was varied experimentally in nature and two measures of size of the fat reserve were taken at food-supplemented sites and non-supplemented sites. 2In two winters, most of the seven species sampled showed slightly higher visible subcutaneous fat class at supplemented than at non-supplemented sites; treatment and species factors were statistically significant. Body mass corrected for wing length showed a similar if non-significant trend. 3A parallel dispersal study of birds colour-banded at non-supplemented sites showed that these birds did not move 0·8 or 1·5 km to use supplemental food at private feeding stations in the study areas. In addition, accipiter hawk attack rate did not differ between supplemented and non-supplemented sites. 4These results are consistent with a model of adaptive fat regulation (based on between-day environmental variability caused by severe weather events) that predicts an increase in the winter fat reserve at increased food supply. Other published studies, all from the north temperate zone, showed the same pattern. 5The present results are inconsistent with a second model (based on within-day foraging interruption) which predicts a decrease in the fat reserve under increased food supply. However, a set of published studies, all from tropical regions or regions with mild maritime climate, showed the decrease at higher food predicted by the second but not the first model. 6Models of adaptive fat regulation in small birds are therefore limited in their predictive power, perhaps because they are developed for environments that differ in the time scale of environmental stochasticity. New studies are needed that explore further the complexities of environment-specific adaptive fat models, e.g. a winter feeding experiment in a tropical bird species. [source]

    Food limitation explains most clutch size variation in the Nazca booby

    JOURNAL OF ANIMAL ECOLOGY, Issue 4 2001
    L. D. Clifford
    Summary 1,Natural selection is expected to optimize clutch size, but intrapopulation variation is maintained in many bird species. The Nazca booby provides a simple system in which to investigate clutch size evolution because clutch size and brood size are decoupled due to obligate siblicide. The indirect effect of brood size on clutch size evolution can therefore be eliminated. 2,In Nazca boobies, second eggs provide insurance against the failure of the first egg or early death of the first hatchling, but approximately half of all females lay only one egg. We tested the hypothesis that one-egg clutches result from food limitation by providing female Nazca boobies with supplemental food. 3,A higher proportion of supplemented females produced two-egg clutches than did control females. Supplemented females produced larger second-laid eggs than did control females, but not first-laid eggs. Laying date and laying interval were not affected. 4,Comparisons of clutch size and egg volume between years indicated that the supplemental feeding experiment was not conducted in a year with a poor natural food supply. Thus supplemented females produced larger clutch sizes despite apparently normal natural food levels. 5,This experiment nearly completes our understanding of clutch size variation in the Nazca booby, and indicates that food limitation and the costs of egg-laying should be considered carefully in studies of clutch size evolution. [source]

    Does supplementary feeding reduce predation of red grouse by hen harriers?

    JOURNAL OF APPLIED ECOLOGY, Issue 6 2001
    Stephen M. Redpath
    Summary 1Hen harriers Circus cyaneus can reduce the numbers of red grouse Lagopus lagopus scoticus available for shooting. We conducted a supplementary feeding experiment on Langholm Moor, UK, in 1998 and 1999 to determine whether feeding hen harriers could reduce the numbers of red grouse killed. The experiment was done at two distinct stages of the breeding cycle: prior to incubation (spring experiment) and after hatching (summer experiment). In spring, Langholm Moor was divided into two areas, one with food and one without. In summer a number of birds were provided with food in both areas. 2Providing harriers with food in spring had no significant effect on the breeding density of males or females, although feeding was associated with an increase in density on one area in one year. In addition, over the 2 years of the experiment, there was no evidence that feeding led to more chicks returning to breed in subsequent years. Fed harriers had larger clutches but did not lay earlier than unfed birds. 3A minimum of 78% of the radio-tagged grouse that were killed during spring were killed by raptors. The mortality rates of adult grouse did not differ between the two areas or between the two years despite the availability of supplementary food and the large differences in harrier breeding density between areas. We infer that other raptors were responsible for much of the predation of adult grouse. 4During the nestling period, female harriers took supplementary food at a higher rate than males. Females that were fed during the spring took more supplementary food in summer than those fed only during summer. Fed birds did not deliver more food overall to nests than those not provided with food. 5Both male and female harriers at nests where supplementary food was available caught grouse chicks at a lower rate than harriers at nests not provided with food. For both years combined, fed harriers delivered on average 0·5 grouse chicks to their nests per 100 h, compared with 3·7 grouse chicks delivered to nests without supplementary food. 6We estimated that feeding all harriers at Langholm would cost approximately Ł11 000 per annum. In both 1998 and 1999, the numbers of grouse chicks lost were 10 times higher than expected from harrier predation rates. Some other, unknown, factor had a strong influence on grouse chick survival in these years. Feeding some of the breeding harriers did not lead to an increase in grouse density at Langholm. 7The results suggest that supplementary feeding may provide a useful tool in reducing the number of grouse chicks taken by harriers. Further experiments are now necessary to see under what conditions this reduced predation will lead to increases in grouse density. [source]

    Influence of dietary amino acid profiles on growth performance and body composition of juvenile grouper Epinephelus coioides

    JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2008
    Z. Luo
    Summary A feeding experiment was conducted to investigate the effects of dietary amino acid (AA) profiles on growth performance and body composition of juvenile grouper Epinephelus coioides (initial mean weight: 68.1 ± 1.0 g, mean ± SD). Five diets contained 30% fishmeal, 12% soy protein concentrate and 20% crystalline amino acids (CAAs); the control diet contained 54% fishmeal and 17% soy protein concentrate as intact protein sources. CAAs were added to the five diets to simulate the AA pattern found in white fishmeal protein (WFP), brown fishmeal protein (BFP), hen egg protein (HEP), grouper E. coioides juvenile protein (GJP) and red sea bream egg protein (REP), respectively. The highest WG and SGR were obtained in fish fed the control diet, followed by fish fed the diets with AA profiles of WFP and GJP. Fish fed the diets with AA profiles of BFP, REP and HEP showed relatively poor growth performance. Feed utilization showed a similar trend in growth parameters. Protein content of whole body among these treatments showed no significant differences (P > 0.05), but lipid content of whole body showed the highest value in the control group (P < 0.05). Dietary AA profiles significantly influenced plasma protein, cholesterol, triacylglycerol and glucose concentrations (P < 0.05). Dietary AA profiles significantly influenced the condition factor, hepatosomatic index and intraperitoneal fat ratio (P < 0.05). [source]

    Detection and distribution of probiotic Escherichia coli Nissle 1917 clones in swine herds in Germany

    JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006
    S. Kleta
    Abstract Aims:, To verify the presence of Escherichia coli Nissle 1917 as a natural isolate in swine and to characterize in vitro probiotic properties as well as in vivo persistence in a feeding experiment. Methods and Results:, During studies on the intestinal microflora of pigs, we isolated E. coli Nissle 1917 sporadically from a pig population over a period of 1 year. The identity of the isolates as E. coli Nissle 1917 was verified by serotyping, Nissle-specific PCR, macrorestriction analysis (pulsed field gel electrophoresis) and the determination of in vitro probiotic properties in invasion and adhesion assays using a porcine intestinal epithelial cell line. Both the E. coli isolates and the E. coli Nissle 1917 strain showed strong reductions in adhesion of porcine enteropathogenic E. coli and invasion of Salmonella typhimurium with epithelial cells in vitro, with a probiotic effect. Screening of five epidemiologically unlinked swine farms and two wild boar groups showed one farm positive for E. coli Nissle 1917. A feeding experiment with four piglets showed viable E. coli Nissle 1917 in the intestine of three animals. Conclusions:, The results of this study suggest that the E. coli Nissle 1917 strain is already partially established in swine herds, but the colonization of individual animals is variable. Significance and Impact of the Study:, We report natural, long-term colonization and transmission of the probiotic E. coli Nissle 1917 strain in a swine herd, characterized individual persistence and colonization properties in swine and established an in vitro porcine intestinal epithelial cell model of probiotic action. The results of this study would have implications in the use of this strain as a probiotic in swine and contribute to a better understanding of the individual nature of intestinal bacterial persistence and establishment. [source]

    Prey availability directly affects physiology, growth, nutrient allocation and scaling relationships among leaf traits in 10 carnivorous plant species

    JOURNAL OF ECOLOGY, Issue 1 2008
    Elizabeth J. Farnsworth
    Summary 1Scaling relationships among photosynthetic rates, leaf mass per unit area (LMA), and foliar nitrogen (N) and phosphorus (P) content hold across a diverse spectrum of plant species. Carnivorous plants depart from this spectrum because they dedicate substantial leaf area to capturing prey, from which they derive N and P. We conducted a manipulative feeding experiment to test whether scaling relationships of carnivorous plant leaf traits become more similar to those of non-carnivorous taxa when nutrients are not limiting. 2We examined the effects of prey availability on mass-based maximum photosynthetic rate (Amass), chlorophyll fluorescence, foliar nutrient and chlorophyll content, and relative growth rate of 10 Sarracenia species. We hypothesized that increased prey intake would stimulate Amass, reduce stress-related chlorophyll fluorescence, increase photosynthetic nutrient-use efficiencies (PNUEN, PNUEP), and increase relative biomass allocation to photosynthetically efficient, non-carnivorous phyllodes. 3Two plants per species were assigned in a regression design to one of six weekly feedings of finely ground wasps: 0,0.25 g for small plant species; 0,0.5 g for intermediate-sized species; and 0,1.0 g for large species. The first two leaves emerging on each plant were fed. 4Increased prey availability increased photosystem efficiency (Fv/Fm ratio) in the first two leaves, and chlorophyll content and Amass in younger leaves as older leaves rapidly translocated nutrients to growing tissues. Higher prey inputs also led to lower N : P ratios and a shift from P- to N-limitation in younger leaves. PNUEP was significantly enhanced whilst PNUEN was not. Better-fed plants grew faster and produced a significantly higher proportion of phyllodes than controls. 5Feeding shifted scaling relationships of P relative to Amass, N and LMA from outside the third bivariate quartile to within the 50th bivariate percentile of the universal spectrum of leaf traits; other scaling relationships were unaffected. Carnivorous plants can rapidly reallocate P when nutrients are plentiful, but appear to be less flexible in terms of N allocation. 6Synthesis. Our results support the general hypothesis put forward by Shipley et al. (2006) that observed scaling relationships amongst leaf traits derive from trade-offs in allocation to structural tissues vs. liquid-phase (e.g. photosynthetic) processes. These trade-offs appear to be especially constraining for plants growing in extremely nutrient-poor habitats such as bogs and other wetlands. [source]

    Effect of Dietary Protein Sources on Growth and Body Composition of Snail, Semisulcospira gottschei

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2010
    Sang-Min Lee
    A feeding experiment was conducted to determine a dietary protein source for juvenile snail, Semisulcospira gottschei. Eight experimental diets (designated as 1,8) were formulated to contain 31% casein, 42% fish meal, 31% blood meal, 39% meat meal, 46% corn gluten meal, 57% soybean meal, 50% cottonseed meal with 23% casein, and 50% wheat flour with 6% casein, respectively, as dietary sole protein sources. Snails (37 ± 3.4 mg/snail) were randomly distributed into 25 L aquaria (20 L water each) in a recirculating aquarium system at a density of 100 juveniles per aquarium. Three replicate groups of snails were fed one of the experimental diets ad libitum once in every 2 d for 12 wk. At the end of the feeding experiment, survival of snails ranged from 77 to 89%, and was not significantly different among the treatments. Snails fed Diet 7 containing 25.3% crude protein deriving from cottonseed meal and casein grew faster than did snails fed other diets, except for snails fed Diet 6 containing soybean meal as a protein source. Growth of snails fed diets containing blood meal, corn gluten meal, and meat meal was the least of snails fed any diet. Crude protein, crude lipid, and ash contents of whole body varied remarkably with dietary protein source. The present findings suggest that dietary protein source could affect the body weight and proximate composition of snails. Cottonseed meal and soybean meal might be a more preferable dietary protein source for snail juvenile compared with other ingredients tested. [source]

    Optimum Dietary Level of L-ascorbic Acid for Japanese Eel, Anguilla japonica

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2005
    Toncaun Ren
    A feeding experiment was conducted to determine the optimum dietary level of ascorbic acid (AsA) for Japanese eel juveniles using L-ascorbic acid Ca based on growth, AsA content in tissues, hematology, and bactericidal activity of serum with Escherichia coli. Test diets with six levels of AsA (3, 10, 27,126, 645, and 3,135-mg/kg diet) as Ca ascorbate were fed to juvenile Japanese eels (11.0 ± 0.2 g) once a day for 8 wk. High survival rates (> 80%) were observed among all dietary treatment groups. The specific growth rates of the fish fed diets containing 3 and 10-mg AsA/kg were significantly (P < 0.05) lower than those of other groups. Liver and brain AsA contents of the fish fed diets containing 3, 10, and 27-mg AsA/kg were significantly (P < 0.05) lower than those of the fish fed diets containing 645 and 3,135-mg AsA/kg. Hemoglobin content tended to be higher in the fish fed diets containing 645 and 3,135-mg AsA/kg than those of the fish fed other diets. Hematocrit value and total serum protein content of the fish fed diets containing 645 and 3135 mg AsA/kg were significantly (P < 0.05) higher than those of the other groups. The fish fed diets containing more than 27-mg AsAlkg showed a higher bactericidal activity of serum than the fish fed the diets containing 3-mg and 10-mg AsA/kg. The optimum dietary level of AsA for the Japanese eel juveniles growth was estimated to be more than 27-mg AsA/kg. Furthermore, the inclusion of 645-mg AsA/kg or more also increased the hematocrit, hemoglobin, total serum protein value, and liver and brain vitamin C concentrations. [source]

    Effects of Dietary Vitamin A on Juvenile Red Sea Bream Chrysophrys major

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2004
    Luis Hector
    A 55-d feeding experiment was conducted to evaluate the effects of dietary vitamin A on growth of juvenile red sea bream Chrysophrys major. Nine semi-purified diets with supplemental retinol palmitate at levels of 0, 300, 600, 1,500, 3,000, 4,500, 6,000, 15,000 and 30,000 retinol eq/kg diet, were fed twice daily to triplicate groups of 10 juveniles per tank with an initial weight of 1.178 ± 0.001 g. Weight gain and specific growth rate increased with the increase of supplemental retinol palmitate in the diet up to a level of 6,000 retinol eq/kg diet, beyond which those indices tended to decrease slightly or to plateau. Significantly lower weight gain and specific growth rate were observed in fish fed with 0 and 300 retinol eq/kg diet. No significant differences were found in survival rates among the different levels of supplementation. The crude protein, lipid, moisture and ash contents in the whole body were not affected by the different vitamin A supplemental levels. Besides the reduced growth, fish fed with low levels of vitamin A supplement showed no other signs of deficiency. No hypervitaminosis A symptoms were observed in fish fed on high levels of supplementation. Fish fed on diets with 0 and 300 retinol eq/kg diet showed a significantly lower content of vitamin A (as a total retinol) in the liver than those in groups fed with higher levels of supplementation. Vitamin A was stored in the liver mainly as retinyl esters. Total retinal content of the eye showed no significant differences among the treatments; however, fish fed with 0 and 300 retinol eq/kg of diet had slightly higher concentrations. According to the results of the mean weight gain, specific growth rate and liver retinol content, the requirement of dietary vitamin A for juvenile red sea bream was estimated to be between 1,500 and 6,000 retinol eq/kg. [source]

    Effects of dietary protein and lipid levels on growth and energy productive value of pacific white shrimp, Litopenaeus vannamei, at different salinities

    AQUACULTURE NUTRITION, Issue 4 2010
    X.Z. ZHU
    Abstract A 8-week feeding experiment was conducted to evaluate the effect of different dietary protein and lipid levels on growth and energy productive value of juvenile Litopenaeus vannamei, at 30 and 2 ppt, respectively. Nine practical diets were formulated to contain three protein levels (380, 410 and 440 g kg,1) and three lipid levels (60, 80 and 100 g kg,1). Each diet was randomly fed to triplicate groups of 30 shrimps per tank (260 L). The effects of salinity and an interaction between dietary protein level and lipid level on growth and energy productive value of shrimp were observed under the experimental conditions of this study. At 30 ppt seawater, shrimp fed with 440 g kg,1protein diets had significantly higher weight gain (WG) than those fed with 380 g kg,1 protein diets at the same dietary lipid level, and the 60 g kg,1 lipid group showed higher growth than 80 g kg,1and 100 g kg,1 lipid groups at the same dietary protein level. At 2 ppt seawater, the growth of shrimp was little affected by dietary protein treatments when shrimp fed the 80 and 100 g kg,1 lipid, shrimp fed the 80 g kg,1 lipid diets had only slightly higher growth than that fed 60and 100 g kg,1 lipid diets when fed 380 and 410 g kg,1 dietary protein diets. A significant effect of salinity on growth of shrimp was detected with the growth responses at 30 ppt > 2ppt (P < 0.05). Final body lipid content, body protein content and energy productive value of shrimp was significantly higher in animals exposed to 30 ppt than in shrimp held at 2 ppt. [source]

    Estimation of dietary biotin requirement of Japanese seabass, Lateolabrax japonicus C.

    AQUACULTURE NUTRITION, Issue 3 2010
    J. LI
    Abstract A 9-week feeding experiment was conducted to determine the dietary biotin requirement of Japanese seabass, Lateolabrax japonicus C. Six isonitrogenous and isoenergetic purified diets (Diets 1,6) containing 0, 0.01, 0.049, 0.247, 1.238 and 6.222 mg biotin kg,1 diet were fed twice daily to triplicate groups (30 fish per group) of fish (initial average weight 2.26 ± 0.03 g) in 18 fibreglass tanks (300 L) filled with 250 L of water in a flow-through system. Water flow rate through each tank was 2 L min,1. Water temperature ranged from 25.0 to 28.0 °C, salinity from 28.0 to 29.5 g L,1, pH from 8.0 to 8.1 and dissolved oxygen content was approximately 7 mg L,1 during the experiment. After the feeding experiment, fish fed Diet 1 developed severe biotin deficiency syndromes characterized by anorexia, poor growth, dark skin colour, atrophy and high mortality. Significant lower survival (73.3%) was observed in the treatment of deficient biotin. The final weight and weight gain of fish significantly increased with increasing dietary biotin up to 0.049 mg kg,1 diet (P < 0.05), and then slightly decreased. Both feed efficiency ratio and protein efficiency ratio showed a very similar change pattern to that of weight gain. Dietary treatments did not significantly affect carcass crude protein, crude lipid, moisture and ash content. However, liver biotin concentration (0,6.1 ,g g,1) significantly increased with the supplementation of dietary biotin (P < 0.05), and no tissue saturation was found within the supplementation scope of biotin. Broken-line regression analysis of weight gain showed that juvenile Japanese seabass require a minimum of 0.046 mg kg,1 biotin for maximal growth. [source]

    Quantitative l -lysine requirement of juvenile black sea bream (Sparus macrocephalus)

    AQUACULTURE NUTRITION, Issue 2 2010
    F. ZHOU
    Abstract An 8-week feeding experiment was conducted to determine the quantitative l -lysine requirement of juvenile black sea bream Sparus macrocephalus (initial mean weight: 9.13 ± 0.09 g, SD) in eighteen 300-L indoors flow-through circular fibreglass tanks provided with sand-filtered aerated seawater. The experimental diets contained six levels of l -lysine ranging from 20.8 to 40.5 g kg,1 dry diet at about 4 g kg,1 increments. All the experiment diets were formulated to be isoenergetic and isonitrogenous. Each diet was assigned to triplicate groups of 20 fish in a completely randomized design. Weight gain and specific growth rate (SGR) increased with increasing levels of dietary lysine up to 32.5 g kg,1 (P < 0.05) and both showed a declining tendency thereafter. Feed efficiency ratio and protein efficiency ratio was poorer for fish fed the lower lysine level diets (P < 0.05) and showed no significant differences among other treatments (P > 0.05). All groups showed high survival (above 90%) and no significant differences were observed. The whole body crude protein and crude lipid contents were significantly affected (P < 0.05) by dietary lysine level, while moisture and ash showed no significant differences. The composition of muscle and liver also presented similar change tendency. Total essential amino acid and lysine contents in muscle both obtained the highest value when fish fed 32.5 g kg,1 lysine diet (P < 0.05). Serum protein, cholesterol and free lysine concentration were affected by different dietary treatments (P < 0.05), triacylglyceride and glucose contents were more variable and could not be related to dietary lysine levels. Dietary lysine level significantly affected condition factor and intraperitoneal fat ratio of juvenile black sea bream (P < 0.05) except for hepatosomatic index. There were no significant differences in white blood cell count and red blood cell count (P > 0.05), however, haemoglobin level was significantly influenced by different diets (P < 0.05). Analysis of dose (lysine level)-response (SGR) with second order polynomial regression suggested the dietary lysine requirement of juvenile black sea bream to be 33.2 g kg,1 dry diet or 86.4 g lysine kg,1 protein. [source]

    Effect of methionine on intestinal enzymes activities, microflora and humoral immune of juvenile Jian carp (cyprinus carpio var. Jian)

    AQUACULTURE NUTRITION, Issue 5 2009
    L. TANG
    Abstract An 8-week feeding experiment was conducted to determine the effect of dietary methionine supplementation on intestinal microflora and humoral immune of juvenile Jian carp (initial weight of 9.9 ± 0.0 g) reared in indoor flow-through and aerated aquaria. Eight amino acid test diets (350 g kg,1 crude protein, CP), using fish meal, soybean-condensed protein and gelatin as intact protein sources supplemented with crystalline amino acids, were formulated to contain graded levels of methionine (0.6,22.0%) at a constant dietary cystine level of 3 g kg,1. Each diet was randomly assigned to three aquaria. Growth performance and feed utilization were significantly influenced by the dietary methionine levels (P < 0.05). Maximum weight gain, feed intake occurred at 12 g kg,1 dietary methionine (P < 0.05). Methionine supplementation improved hepatopancreas and intestine weight, hepatosomatic and intestine index, intestinal ,-glutamyltransferase and creatine kinase activity, Lactobacillus count, Bacillus count, lysozyme activities, lectin potency, sim-immunoglobulin M content, addiment C3,C4 contents and serum total iron-binding capacity and declined Escherichia coli and Aeromonas counts. Quadratic regression analysis of weight gain against dietary methionine levels indicated that the optimal dietary methionine requirement for maximum growth of juvenile Jian carp is 12 g kg,1 of the dry diet in the presence of 3 g kg,1 cystine. [source]

    Effects of dietary vitamin E supplementation on growth performance, lipid peroxidation and tissue fatty acid composition of black sea bream (Acanthopagrus schlegeli) fed oxidized fish oil

    AQUACULTURE NUTRITION, Issue 3 2009
    S. PENG
    Abstract A 9-week feeding experiment was conducted to evaluate the effects of dietary vitamin E supplementation on growth, lipid peroxidation and fatty acid composition of black sea bream fed oxidized oil. The FL and OL diets contained fresh fish oil and oxidized oil, respectively, without additional vitamin E supplementation. Another four ,-tocopherol levels (150, 250, 450 and 800 mg kg,1 diet) were used within the OL diet, giving a total of six experimental diets. Fish were hand-fed to apparent satiation twice daily. At end of the trial, the weight gain and survival rate of fish were significantly reduced by diets with oxidized oil, whereas hepatosomatic index was remarkably high in fish fed oxidized oil diet. However, vitamin E supplementation to diet significantly improved growth performance and increased vitamin E content in the liver. Although, liver thiobarbituric acid reactive substances and docosahexaenoic acid were significantly increased by dietary oxidized oil, their levels were reduced by dietary vitamin E supplementation. Our results indicate that the fish were performing the best at intermediate concentrations of ,-tocopherol and a dose of >150 mg ,-tocopherol kg,1 diet could reduce lipid peroxidation and improve fish growth performance when oxidized oils exist in diet. [source]

    Growth and body composition of juvenile white shrimp, Litopenaeus vannamei, fed different ratios of dietary protein to energy

    AQUACULTURE NUTRITION, Issue 6 2008
    Y. HU
    Abstract A 10-week feeding experiment was conducted to evaluate the effect of different protein to energy ratios on growth and body composition of juvenile Litopenaeus vannamei (initial average weight of 0.09 ± 0.002 g, mean ± SE). Twelve practical test diets were formulated to contain four protein levels (300, 340, 380 and 420 g kg,1) and three lipid levels (50, 75 and 100 g kg,1). Each diet was randomly fed to triplicate groups of 30 shrimps per tank (260 L). The water temperature was 28.5 ± 2 °C and the salinity was 28 ± 1 g L,1 during the experimental period. The results showed that the growth was significantly (P < 0.05) affected by dietary treatments. Shrimps fed the diets containing 300 g kg,1 protein showed the poorest growth. However, shrimp fed the 75 g kg,1 lipid diets had only slightly higher growth than that fed 50 g kg,1 lipid diets at the same dietary protein level, and even a little decline in growth with the further increase of dietary lipid to 100 g kg,1. Shrimp fed the diet with 420 g kg,1protein and 75 g kg,1 lipid had the highest specific growth rate. However, shrimp fed the diet with 340 g kg,1 protein and 75 g kg,1 lipid showed comparable growth, and had the highest protein efficiency ratio, energy retention and feed efficiency ratio among dietary treatments. Triglycerides and total cholesterol in the serum of shrimp increased with increasing dietary lipid level at the same dietary protein level. Body lipid and energy increased with increasing dietary lipid level irrespective of dietary protein. Results of the present study showed that the diet containing 340 g kg,1 protein and 75 g kg,1 lipid with digestible protein/digestible energy of 21.1 mg kJ,1 is optimum for L. vannamei, and the increase of dietary lipid level has not efficient protein-sparing effect. [source]

    Influence of several non-nutrient additives on nonspecific immunity and growth of juvenile turbot, Scophthalmus maximus L.

    AQUACULTURE NUTRITION, Issue 5 2008
    Y. LI
    Abstract The effects of three non-nutrient additives on nonspecific immunity and growth of juvenile turbot (Scophthalmus maximus L.) were studied in this feeding experiment. The five treatments are basal diet alone, basal diets containing three different additives [0.4 g kg,1 of xylo-oligosaccharides (XOS), 1.3 g kg ,1 of yeast cell wall and 0.8 g kg ,1 of bile acids] individually or in combination. Two hundred and twenty-five turbots (average initial weight 151.3 ± 11.3 g) were randomly allotted in five treatments with three replicates within each treatment in a 72-day period. Comparing with basal diet group, activities of C3, C4, phagocyte, lysozyme, specific growth rate and feed conversion rate in yeast cell wall, XOS and the combined groups was enhanced significantly (P < 0.05); however, these parameters in bile acid groups were increased slightly (P > 0.05) except for phagocyte (P < 0.05); superoxide dismutase activity in additive groups was not significantly increased (P > 0.05) except for the combined group (P < 0.05). In conclusion, supplementation of yeast cell wall and XOS enhanced the nonspecific immunity of juvenile turbot. Synergistic or additive effect of the three additives was not observed. [source]

    Substituting fish meal with poultry by-product meal in diets for black Sea turbot Psetta maeotica

    AQUACULTURE NUTRITION, Issue 5 2006
    M. YIGIT
    Abstract A 60 days feeding experiment was carried out with Black Sea turbot Psetta maeotica to determine the amount of poultry by-product meal (PBM) that could replace fish meal (FM) in formulated diets without reducing growth performance. Juvenile Black Sea turbot (initial average weight, 30 g) were fed five isoenergetic (gross energy, 20.5 ± 0.21 kJ g,1 diet) and isonitrogenous diets (protein content, 550 ±,0.35 g kg,1). The control diet used white FM as the sole protein source, the other four diets were prepared to replace FM protein at levels of 25%, 50%, 75% and 100% with PBM. The fish readily accepted all experimental diets and no mortality were recorded during the trial. There were no significant differences in growth performance of turbot (P < 0.05) fed the diets with 25% and 50% replacement levels compared with fish offered the control diet (100% FM), however, final body weight and specific growth rate values in the 50% replacement diet were about 8% lower than those of the control. Total nitrogen excretion in fish fed 50% replacement diet were about 10% higher than the control group, even though these parameters were not found to be statistically different. At the levels of 750 and 1000 g kg,1 of the protein, PBM inclusion caused a severe decrease in growth performance, feed utilization, protein efficiency ratio and per cent nitrogen retention. The results in the present study indicate that up to 25% of FM protein can be replaced by PBM protein without causing reduction in growth performance, nutrient utilization and nitrogen retention. [source]

    Partial replacement of fishmeal by soybean meal in diets for juvenile cobia (Rachycentron canadum)

    AQUACULTURE NUTRITION, Issue 3 2005
    Q.-C. ZHOU
    Abstract An 8-week feeding experiment was conducted in floating cages (1.5 × 1.0 × 2.0 m) to determine the potential use of defatted soybean meal (roasted and solvent-extracted) as a partial replacement of fishmeal in the isonitrogenous (approximately 450 g kg,1 CP [crude protein]) diet for juvenile cobia with an initial average weight of about 8.3 g. Diets were formulated to include 0, 100, 200, 300, 400, 500 and 600 g kg,1 (diets D0, D10, D20, D30, D40, D50 and D60, respectively) of fishmeal protein being substituted by defatted soybean meal without methionine supplementation. The results showed that weight gain rate decreased significantly when the replacement level of fishmeal protein was increased from 400 g kg,1 to 500 g kg,1, and the D60 diet was the lowest in all groups. These results indicate that up to 400 g kg,1 of fishmeal protein can be replaced by defatted soybean meal without causing significant reduction in growth. Feed conversion ratio (FCR) and protein efficiency ratio (PER) were significantly affected by the replacement level of fishmeal protein being substituted by defatted soybean meal, when the replacement level of fishmeal protein was 200 g kg,1 (diet, D20), FCR was the lowest and PER was the highest. There were no significant differences in the moisture, lipid, crude protein and ash content in whole body and muscle, while lipid content in liver increased as the dietary soybean meal replacement levels increased. There were significant differences in haemoglobin, haematocrit, red blood cell, plasma glucose and triglyceride concentration in fish fed diets with different soybean meal replacement levels. Results of this trial indicated that the optimum level of fishmeal protein replacement with defatted soybean meal, determined by quadratic regression analysis was 189.2 g kg,1, on the basis of maximum weight gain. [source]

    Dietary vitamin A requirements of juvenile Japanese flounder Paralichthys olivaceus

    AQUACULTURE NUTRITION, Issue 1 2005
    L.H.H. HERNANDEZ
    Abstract A 70-day feeding experiment was conducted to assess the dietary vitamin A (VA) requirements of juvenile Japanese flounder (Paralichthys olivaceus). Six semi-purified diets with VA supplementations of 0, 5000, 10 000, 15 000, 20 000 and 25 000 IU kg,1 were fed twice a day to triplicate groups of 20 juveniles per tank with an initial weight of 1.59 ± 0.01 g (mean ± SE). Weight gain (WG) and specific growth rate (SGR) increased as dietary VA increased up to 10 000 IU kg,1. Significantly lower WG and SGR were observed for the 0 IU kg,1 treatment than for treatments of 5000, 10 000 and 15 000 IU kg,1. Highest WG and SGR were observed in fish fed 10 000 IU kg,1; slightly lower values were recorded in fish fed 15 000, 20 000 or 25 000 IU kg1. No significant difference was observed in survival rate among treatments. Whole body total lipid was significantly higher in fish fed 0 and 5000 IU kg,1 than for other levels. Reduced growth and small livers were observed as signs of VA deficiency in fish fed 0 IU kg,1. Slightly reduced growth and pale fragile livers were observed as effects of VA excess in fish fed 25 000 IU kg,1. Total retinol contents in liver and eyes increased with increasing levels of dietary VA. No retinol was detected in livers, and significantly lower total retinol content was observed in eyes, of fish fed 0 IU kg,1. WG analysed by the broken line method indicated that an optimum dietary VA requirement of 9000 IU kg,1. [source]

    Digestibility and growth performance of juvenile rainbow trout (Oncorhynchus mykiss) fed with pea and canola products

    AQUACULTURE NUTRITION, Issue 2 2003
    D.L. Thiessen
    A digestibility experiment and subsequent 84-day feeding experiment evaluated the use of pea and canola meal products in diets for rainbow trout. The effect of milling and heat treatment on nutrient, dry matter and energy digestibility of raw/whole peas, raw/dehulled peas, extruded/dehulled peas and autoclaved air-classified pea protein was determined. Digestibility of the protein component was uniformly high for all pea ingredients (90.9,94.6%), regardless of the processing treatment. Autoclaving or extrusion increased starch digestibility by 41,75% (P , 0.05), which consequently increased energy and dry matter digestibility of whole and dehulled peas. Autoclaved air-classified pea protein had superior protein (94.6%), energy (87.0%) and dry matter (84.0%) digestibility (P , 0.05). It was demonstrated that inclusion of 25% dehulled peas, 20% air-classified pea protein or 20% canola meal fines was feasible in trout diets allowing for replacement of soya bean meal. The data showed no difference (P , 0.05) in feed intake, final weight and specific growth rate (SGR) measurements, and feed utilization was not compromised with inclusion of pea or canola meal products as the primary plant ingredient. It was concluded that dehulled peas, air-classified pea protein and canola meal fines are suitable ingredients for use in trout diet formulation at a level of 20%. [source]

    Effect of hot water extracts of brown seaweeds Sargassum spp. on growth and resistance to white spot syndrome virus in shrimp Penaeus monodon postlarvae

    AQUACULTURE RESEARCH, Issue 10 2010
    Grasian Immanuel
    Abstract An experiment was conducted to evaluate the effect of a hot water extract of brown seaweeds Sargassum duplicatum and Sargassum wightii on the growth and white spot syndrome virus (WSSV) resistance in shrimp Penaeus monodon postlarvae (PL). Artemia nauplii (instar II) were enriched with both seaweed extracts at various concentrations (250, 500 and 750 mg L,1) and fed to the respective P. monodon (PL15,35) group for 20 days. A control group was also maintained without seaweed extract supplementation. The weight gain of the experimental groups was significantly higher (0.274,0.323 g) than the control group (0.261 g). Similarly, the specific growth rate was also significantly higher (16.27,17.06%) in the experimental groups than in the control group (16.03%). After 20 days of the feeding experiment, the shrimp PL were challenged with WSSV for 21 days. During the challenge test, the control shrimp displayed 100% mortality within 8 days. In contrast, the mortality percentage of the highest concentration (750 mg L,1) of seaweed extract enriched Artemia nauplii fed shrimp was 54,79%. Comparatively, low mortality was observed in S. wightii extract-enriched Artemia nauplii fed shrimp. The polymerase chain reaction analysis indicated the concentration-dependent infection of WSSV in P. monodon PL. [source]