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Acid Requirements (acid + requirement)

Distribution by Scientific Domains

Earth and Environmental Science	85%

Kinds of Acid Requirements

amino acid requirement

Selected Abstracts

Estimating Amino Acid Requirement of Brazilian Freshwater Fish from Muscle Amino Acid Profile

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 6 2009
ÁLvaro José De Almeida Bicudo
Information on nutritional requirement of some Brazilian farmed fish species, especially essential amino acids (EAA) requirements, is scarce. The estimation of amino acids requirements based on amino acid composition of fish is a fast and reliable alternative. Matrinxa, Brycon amazonicus, and curimbata, Prochilodus lineatus, are two important Brazilian fish with potential for aquaculture. The objective of the present study was to estimate amino acid requirements of these species and analyze similarities among amino acid composition of different fish species by cluster analysis. To estimate amino acid requirement, the following formula was used: amino acid requirement = [(amount of an individual amino acid in fish muscle tissue) × (average totalEAA requirement among channel catfish, Ictalurus punctatus, Nile tilapia, Oreochromis niloticus, and common carp, Cyprinus carpio)]/(average fish muscle totalEAA). Most values found lie within the range of requirements determined for other omnivorous fish species, in exception of leucine requirement estimated for both species, and arginine requirement estimated for matrinxa alone. Rather than writing off the need for regular dose,response assays under the ideal protein concept to determine EAA requirements of curimbata and matrinxa, results set solid base for the study of tropical species dietary amino acids requirements. [source]

Potential for protein deposition and threonine requirement of modern genotype barrows fed graded levels of protein with threonine as the limiting amino acid

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5-6 2004
H. T. Thong
Summary The study was conducted to estimate the actual genetic potential for daily protein deposition of growing barrows [genotype: Piétrain × (Duroc × Landrace)]. Twenty-four pigs with an average initial body weight (BW) of 43.7 ± 0.7 kg were used in a N-balance study. Semi-purified diets with graded levels of crude protein (45.8, 94.2, 148.0, 198.9, 255.5 and 300.2 g/kg DM) were used, based on a constant mixture of wheat, soya bean protein concentrate and potato protein concentrate as protein sources. The amino acid pattern of the diets was according to the ideal amino acid ratio for growing pigs (Wang and Fuller, 1989), with the exception of threonine (adjusted as limiting amino acid). N-balance data were used to estimate daily N-maintenance requirement (NMR = 446 mg N/BW/day) by regression method and the theoretical maximum of daily N-retention (PDmaxT = 3115 mg N/BW/day) based on N-utilization model of Gebhardt (1966) using program Mathematica 3.0. The results indicate that PDmaxT of pigs under study is much higher than results from earlier studies with older genotypes. In summary, pigs of modern genotype have a very high genetic potential for daily protein deposition and these actual data are important basic informations for estimation of amino acid requirement within the model used. Threonine requirement data depending on threonine efficieny and protein deposition (8.96, 10.45 and 12.22 g/day for 130, 145 and 160 g daily protein deposition; 50 kg body weight) are discussed. [source]

Estimating Amino Acid Requirement of Brazilian Freshwater Fish from Muscle Amino Acid Profile

Vitamin C Requirements of the Angelfish Pterophylum scalare

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2000
Jozef H. Blom
Ascorbic acid requirements of fishes of the cichlid family appear to vary widely. Juvenile angelfish, a widely produced ornamental cichlid, were maintained on diets containing graded levels of ascorbyl monophosphate. Liver ascorbic acid concentrations after 96 d of feeding were significantly reduced in groups receiving 120 mg or less ascorbic acid equivalents/kg diet. However, no differences in growth or mortality between groups were found, and no external signs of ascorbic acid deficiency were observed, indicating a high resistance of this species against prolonged ascorbic acid deficiency. Based on the long possible life span of angelfish in the aquarium, we proposed a conservative dietary ascorbic acid requirement of 360 mg/ kg diet, necessary to maintain maximum tissue storage of this vitamin. [source]

Re-evaluation of total sulphur amino acid requirement and determination of replacement value of cystine for methionine in semi-purified diets of juvenile Nile tilapia, Oreochromis niloticus

AQUACULTURE NUTRITION, Issue 3 2009
T.N. NGUYEN
Abstract Two feeding experiments were conducted to re-evaluate the total sulphur amino acid (TSAA; methionine and cystine) requirement and determine the replacement value of cystine for methionine of juvenile Nile tilapia (Oreochromis niloticus). Semi-purified diets used in both experiments contained 3510 kcal gross energy and 280 g of protein per kilogram diet from casein, gelatin and crystalline amino acids. The basal diet of the first experiment contained 3.1 g methionine and 0.4 g cystine per kilogram. l -methionine was added to the seven remaining diets at 1.0 g kg,1 increment to produce methionine levels ranging from 3.1 to 10.1 g kg,1 diet. Each diet was fed to four replicate groups of juvenile Nile tilapia (1.28 g mean weight) in a recirculation system for 8 weeks. Broken-line regression analysis of weight gain data indicated that the TSAA requirement of juvenile Nile tilapia was 8.5 g kg,1 of the diet or 30.4 g kg,1 of dietary protein. In the second experiment, TSAA level was set at 95% of the requirement value determined in the first experiment. Seven diets were made with different ratios of l -methionine and l -cystine (20 : 80, 30 : 70, 40 : 60, 50 : 50, 60 : 40, 70 : 30 and 80 : 20, based on an equimolar sulphur basis). Each diet was also fed to four replicate groups of juvenile Nile tilapia (4.14 g mean weight) in a recirculation system for 8 weeks. Regression analysis of weight gain data using broken-line model indicated that cystine (on a molar sulphur basis) could replace up to 49% of methionine requirement in semi-purified diets for juvenile Nile tilapia. [source]

Toward Improved Public Confidence in Farmed Fish Quality: A Canadian Perspective on the Consequences of Diet Selection

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2010
Anthony P. Farrell
Marine fish oils (MFO) are used in salmon diets to mimic the natural diet, to ensure that essential fatty acid requirements for good fish growth and health are met, and to provide salmon flesh with an omega-3 highly unsaturated fatty acid content that can benefit human health. However, an extensive use of MFO in formulated salmonid diets is perceived as an unsustainable use of wild marine fish stocks. In addition, MFOs have a background level of persistent organic pollutants (POPs) unrelated to aquaculture practices. This review considers recently completed studies using alternative lipid sources of terrestrial origin as replacements for MFO and shows that the composition of conventional finfish diets can be altered to reduce the reliance on MFO while concurrently maintaining fish health as well as reducing background levels of POPs. A challenge still ahead is the need for a concerted and sustained outreach to ensure that the public is aware of such improvements to seafood quality so that the preoccupation of the news media with presenting negative images of fish culture to the public is combated. [source]

Estimating Amino Acid Requirement of Brazilian Freshwater Fish from Muscle Amino Acid Profile

Vitamin C Requirements of the Angelfish Pterophylum scalare

A balanced amino acid diet improves Diplodus sargus larval quality and reduces nitrogen excretion

AQUACULTURE NUTRITION, Issue 5 2009
M. SAAVEDRA
Abstract Fish larvae present high amino acid requirements due to their high growth rate. Maximizing this growth rate depends on providing a balanced amino acid diet which can fulfil larval amino acid nutritional needs. In this study, two experimental microencapsulated casein diets were tested: one presenting a balanced amino acid profile and another presenting an unbalanced amino acid profile. A control diet, live feed based, was also tested. Trials were performed with larvae from 1 to 25 days after hatching (DAH). Microencapsulated diets were introduced at 8 DAH in co-feeding with live feed and at 15 DAH larvae were fed the microencapsulated diets alone. Results showed a higher survival for the control group (8.6 ± 1.3% versus 4.2 ± 0.6% and 3.2 ± 1.8%) although dry weight and growth were similar in all treatments. The proportion of deformed larvae as well as the ammonia excretion was lower in the group fed a balanced diet than in the unbalanced or control groups (38.3% deformed larvae in control, 30% in larvae fed unbalanced diet and 20% on balanced diet group). Furthermore, larvae fed the microencapsulated diets presented higher docosahexaenoic acid and arachidonic acid levels. This study demonstrates that dietary amino acid profile may play an important role in larval quality. It also shows that balanced microencapsulated diets may improve some of the performance criteria, such as skeletal deformities, compared to live feeds. [source]

Amino acid composition of Arctic charr, Salvelinus alpinus (L.) and the prediction of dietary requirements for essential amino acids

AQUACULTURE NUTRITION, Issue 4 2007
R. GURURE
Abstract Embryo somatic tissues, non-somatic yolk-sac materials, and whole, individual fingerlings (age 0+) of Arctic charr, Salvelinus alpinus (L.), as well as a commercial trout diet, were analysed for a wide spectrum of amino acids. Analytical material consisted of prefeeding swim-up fry that were separated into discrete yolk sac and somatic embryo tissue samples. Amino acid concentrations in fry somatic tissue and whole fingerlings were generally very similar to each other, but were lower than those measured in yolk materials. Higher correlations were observed between the majority of specific amino acid concentrations in the trout diet when compared with fingerling data (r2 = 0.91) and fry somatic tissue data (r2 = 0.89), than when correlated with fry yolk sac material (r2 = 0.76). These results indicate that the essential amino acid profiles of fry somatic tissue and whole fingerlings are closer to that of a commercial feed than they are to the endogenous profiles found in the embryonic yolk sac material itself. The dietary ratios of individual essential amino acids were also compared with the total essential amino acid concentrations (A/E ratios) in whole fingerling tissues, and these ratios could be used to accurately estimate the apparent essential amino acid requirements of Arctic charr. The rationale for using carcass amino acid composition data to estimate the dietary essential amino acid requirements of Arctic charr is discussed. [source]

Effect of EPA/DHA ratios on the growth and survival of Galaxias maculatus (Jenyns, 1842) larvae reared under different salinity regimes

AQUACULTURE RESEARCH, Issue 9 2010
Patricio Dantagnan
Abstract Despite the importance of certain highly unsaturated fatty acids in osmotic regulation, few studies have been addressed to determine the essential fatty acid requirements for a given species cultured under different salinities. As Galaxias maculatus is a diadromic species, the present study aimed to determine the effect of salinity on the optimum dietary EPA/docosahexaenoic (DHA) ratio for survival and growth during the larval stages. Larvae were fed for 20 days with rotifers containing two different EPA/DHA ratios (low: 0.64 and high: 2.18) at three different salinities (0, 10 and 15 g L,1). The results of this study showed a marked effect of water salinity on larval dietary lipid utilization in G. maculatus larvae. These results suggested that G. maculatus larvae reared at higher salinities may have a higher dietary requirement for DHA, whereas larvae reared at 0, showed higher requirements for EPA. The overall results of the present study indicate that even small changes in salinity can determine the optimum dietary EPA/DHA ratio and the quantitative essential fatty requirements of fish. This may have important repercussions and affect the rearing performance of G. maculatus cultured under different salinities. [source]

Effects of protein-, peptide- and free amino acid-based diets in fish nutrition

AQUACULTURE RESEARCH, Issue 5 2010
Konrad Dabrowski
In the present review, we summarize data related to the utilization of purified diets formulated with the purpose of determining the amino acid requirements in fish independent of the ontogenetic stage and the morphological characteristics of the digestive tract. Expanding present knowledge on the formulation of protein, free amino acid (FAA) and synthetic dipeptide-based diets can provide possible insights that might lead to a better understanding of the mechanism of amino acid utilization in the growth of fish. Differences exist in the utilization of protein, dipeptides or free amino acids for growth between stomach-possessing and stomachless fish with respect to their response to manipulating the proportion of protein and dipeptides in the formulas. Free amino acid-based diets are uniformly inferior. The effects of diet manipulation on indispensable FAA concentrations in the body (muscle) are not simply the result of deamination or the protein synthesis/degradation ratio. The hydroxyproline/proline ratio was confirmed to be of value in quantifying muscle collagen degradation/synthesis and can perhaps be used to quantify the amino acid requirement necessary to maximize the utilization (deposition) of dietary amino acids. In summary, indispensable amino acid requirements for maximum growth in fish can be addressed using diets formulated from protein/peptide/FAA sources. [source]

Fatty acid requirements in ontogeny of marine and freshwater fish

AQUACULTURE RESEARCH, Issue 5 2010
Douglas R. Tocher
Abstract Essential fatty acid (EFA) requirements vary qualitatively and quantitatively with both species and during ontogeny of fish, with early developmental stages and broodstock being critical periods. Environment and/or trophic level are major factors, with freshwater/diadromous species generally requiring C18 polyunsaturated fatty acids (PUFA) whereas marine fish have a strict requirement for long-chain PUFA, eicosapentaenoic, docosahexaenoic and arachidonic acids. Other than marine fish larvae, defining precise quantitative or semi-quantitative EFA requirements in fish have received less attention in recent years. However, the changes to feed formulations being forced upon the aquaculture industry by the pressing need for sustainable development, namely the replacement of marine fish meal and oils with plant-derived products, have reintroduced EFA into the research agenda. It is particularly important to note that the physiological requirements of the fish to prevent deficiency pathologies and produce optimal growth may not parallel the requirements for maintaining nutritional quality. For instance, salmonids can be successfully cultured on vegetable oils devoid of long-chain n-3 PUFA but not without potentially compromising their health benefits to the human consumer. Solving this problem will require detailed knowledge of the biochemical and molecular basis of EFA requirements and metabolism. [source]

Control of the release of digestive enzymes in the larvae of the fall armyworm, Spodoptera frugiperda

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2010
Digali Lwalaba
Abstract There is a basal level of enzyme activity for trypsin, aminopeptidase, amylase, and lipase in the gut of unfed larval (L6) Spodoptera frugiperda. Trypsin activity does not decrease with non-feeding, possibly because of the low protein levels in plants along with high amino acid requirements for growth and storage (for later reproduction in adults). Therefore, trypsin must always be present so that only a minimal protein loss via egestion occurs. Larvae, however, adjust amylase activity to carbohydrate ingestion, and indeed amylase activity is five-fold higher in fed larvae compared to unfed larvae. Gut lipase activity is low, typical of insects with a high carbohydrate diet. A flat-sheet preparation of the ventriculus was used to measure the release of enzymes in response to specific nutrients and known brain/gut hormones in S. frugiperda. Sugars greatly increase (>300%) amylase release, but starch has no effect. Proteins and amino acids have little or no effect on trypsin or aminopeptidase release. The control of enzyme release in response to food is likely mediated through neurohormones. Indeed, an allatostatin (Spofr-AS A5) inhibits amylase and trypsin, and allatotropin (Manse- AT) stimulates amylase and trypsin release. Spofr-AS A5 also inhibits ileum myoactivity and Manse-AT stimulates myoactivity. The epithelial secretion rate of amylase and trypsin was about 20% of the amount of enzyme present in the ventricular lumen, which, considering the efficient counter-current recycling of enzymes, suggests that the secretion rate is adequate to replace egested enzymes. © 2009 Wiley Periodicals, Inc. [source]