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Luis E C Conceicao - One of the best experts on this subject based on the ideXlab platform.
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stress response and changes in Amino Acid Requirements in senegalese sole solea senegalensis kaup 1858
Amino Acids, 2008Co-Authors: Claudia Aragao, Joana Cortereal, Benjamin Costas, Maria Teresa Dinis, Luis E C ConceicaoAbstract:Fish in aquaculture are often exposed to various stressors that may change their ability to survive or limit growth. Amino Acids are used for processes other than growth, including stress response. This study intended to analyse how repeated acute handling stress can affect growth and Amino Acid Requirements in fish. Senegalese sole juveniles were weekly held in the air during 3 min (Handling) for 9 weeks; Control groups were left undisturbed. Growth and plasma levels of stress indicators and of free Amino Acids were assessed at the end of the experiment. Plasma cortisol and osmolality levels showed that fish in the Handling treatment were stressed, but growth was unaffected. Plasma Amino Acid concentrations indicate that their Requirements in stressed fish were altered, which probably reflects the synthesis of proteins or other specific compounds related to stress response.
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estimated Amino Acid Requirements during early ontogeny in fish with different life styles gilthead seabream sparus aurata and senegalese sole solea senegalensis
Aquaculture, 2004Co-Authors: Claudia Aragao, Luis E C Conceicao, H J Fyhn, Maria Teresa DinisAbstract:Little is known about the Amino Acid (AA) Requirements of larval fish and their possible ontogenetic changes. This paper aims to contribute to the study of these Requirements in two common cultured species in Southern Europe: gilthead seabream (Sparus aurata) and Senegalese sole (Solea senegalensis). Moreover, it is intended to identify possible dietary AA imbalances occurring in normal hatchery conditions for both species. Fish larvae were reared following standard procedures and the normal feeding schemes used in hatcheries, which includes the use of live prey for several weeks. The experiments were finished once the fish were adapted to a dry feed. Samples were collected at different points for dry weight, total protein, and AA analysis. The A/E ratios [each indispensable AA content×(total indispensable AA content including cysteine and tyrosine)−1×1000] of fish and food were compared to identify possible dietary AA imbalances. The AA profile of both fish species changed during ontogeny, but was more stable during seabream than Senegalese sole development. This is probably linked to the marked metamorphosis observed in sole. These changes in fish larval AA profile suggest that the AA Requirements change during seabream and Senegalese sole ontogenesis. Several dietary AA deficiencies were found during the ontogenetic development of both species. These deficiencies result from ontogenetic changes in the fish AA profile, but also from differences in the AA composition of the different food items. These results suggest that both the live food (rotifers and Artemia at different developmental stages) and the dry feed used in the rearing of gilthead seabream and Senegalese sole does not have an AA profile that entirely meets the Requirements for the early stages of these species.
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Amino Acid Requirements of fish larvae and post larvae new tools and recent findings
Aquaculture, 2003Co-Authors: Luis E C Conceicao, H Grasdalen, Ivar RonnestadAbstract:This paper reviews methodologies and recent findings in the study of the Amino Acid (AA) metabolism of fish larvae and post-larvae, in order to better understand the AA Requirements. The larval indispensable AA (IAA) profile can be used as index of the IAA Requirements. When turbot larvae and live food IAA profiles are compared, the profile of the latter seems to be deficient in some IAA. However, the larval IAA profile is only a rough indicator of AA Requirements. A more precise estimate of the ideal dietary IAA profile implies the knowledge of the relative bioavailabilities of the individual AA, in particular, eventual differential rates of absorption and catabolism. Metabolic budgets (including unabsorbed AA, AA oxidation and AA retention) can be estimated using an in vivo method based on controlled tube-feeding of AA mixes containing a 14C-labelled AA. Results with fasted post-larval Senegal sole (Solea senegalensis) and fasted herring (Clupea harengus) larvae show a high retention of labelled doses of IAA (>60%) in the body, compared to catabolism as measured by liberated 14CO2 ( 40%) and a lower retention (<57%). So, from the onset of exogenous feeding, fish larvae have high catabolic losses of AA, but use DAA preferentially to IAA as energy substrates. A new method combining the use of 13C-labelled live food and 13C-NMR spectroscopy can be used to study simultaneously the relative bioavailability of several individual AA in fish larvae. In larval gilthead seabream (Sparus aurata) fed on rotifers, relative bioavailabilities (a combined measure of absorption efficiency and rate of catabolism) vary between AA being high for aspartate, glutamate and lysine and low for threonine. These estimates of relative biovailability of individual AA together with the IAA profiles of the larval seabream indicate that rotifers are deficient in threonine and leucine for larval seabream, threonine being the first limiting AA for protein synthesis. In order to define ideal IAA profiles for larval fish, further studies are needed on the factors affecting the relative bioavailability of IAA, such as species, age, developmental stage, temperature and the dietary nitrogen molecular form(s). Estimates of relative bioavailability of individual AA together with the IAA profile of the larval protein allow to determine the ideal dietary IAA profile for a given species.
Paul B. Pencharz - One of the best experts on this subject based on the ideXlab platform.
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dietary aromatic Amino Acid Requirements during early and late gestation in healthy pregnant women
Journal of Nutrition, 2020Co-Authors: Madeleine Ennis, Ronald O. Ball, Paul B. Pencharz, Annajoy Ong, Kenneth Lim, Glenda Courtneymartin, Rajavel ElangoAbstract:Background Phenylalanine and tyrosine (referred to as total aromatic Amino Acids; TAAs) are essential for protein synthesis, and are precursors for important catecholamines. Current estimated average requirement (EAR) recommendations for TAA during pregnancy are 36 mg·kg-1·d-1, and has not been experimentally determined. Objectives The aim was to determine TAA Requirements (dietary phenylalanine in the absence of tyrosine) during early and late gestation using the indicator Amino Acid oxidation (IAAO, with L-[1-13C]leucine) technique. Methods Nineteen healthy pregnant women (age 22-38 y) were studied at a range of phenylalanine intakes (5 to 100 mg·kg-1·d-1) in early (13-19 wk) and/or late (33-39 wk) pregnancy for a total of 51 study days. Graded test intakes were provided as 8 hourly isonitrogenous and isocaloric meals. Breath samples were collected for 13C enrichment analysis on an isotope ratio mass spectrometer. A plasma sample was collected and analyzed for phenylalanine and tyrosine concentrations on an Amino Acid analyzer. The TAA requirement in early and late pregnancy was calculated using 2-phase linear regression crossover analysis that identified breakpoints in 13CO2 production (the requirement) in response to phenylalanine intakes. Results TAA requirement during early pregnancy was 44 mg·kg-1·d-1 (95% CI: 28.3, 58.8) and during late pregnancy was 50 mg·kg-1·d-1 (95% CI: 36.1, 63.1). In early and late pregnancy, plasma phenylalanine and tyrosine concentrations rose linearly in response to graded phenylalanine intakes. Conclusions Our results suggest that the current EAR of 36 mg·kg-1·d-1 for TAAs is underestimated. When compared with results previously determined in nonpregnant adults, early pregnancy Requirements were similar (43 compared with 44 mg·kg-1·d-1, respectively). During late pregnancy, a 14% higher TAA requirement was observed when compared with early pregnancy. The results from this study have potential implications for creating gestation stage-specific TAA recommendations.
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total sulfur Amino Acid Requirements are not altered in children with chronic renal insufficiency but minimum methionine needs are increased
Journal of Nutrition, 2017Co-Authors: Rajavel Elango, Ronald O. Ball, Mahroukh Rafii, Mohammad A Humayun, Justine M Turner, Veronika Langos, Paul B. PencharzAbstract:Background: The total sulfur Amino Acid (TSAA) and minimum Met Requirements have been previously determined in healthy children. TSAA metabolism is altered in kidney disease. Whether TSAA Requirements are altered in children with chronic renal insufficiency (CRI) is unknown.Objective: We sought to determine the TSAA (Met in the absence of Cys) Requirements and minimum Met (in the presence of excess Cys) Requirements in children with CRI.Methods: Five children (4 boys, 1 girl) aged 10 ± 2.6 y with CRI were randomly assigned to receive graded intakes of Met (0, 5, 10, 15, 25, and 35 mg · kg-1 · d-1) with no Cys in the diet. Four of the children (3 boys, 1 girl) were then randomly assigned to receive graded dietary intakes of Met (0, 2.5, 5, 7.5, 10, and 15 mg · kg-1 · d-1) with 21 mg · kg-1 · d-1 Cys. The mean TSAA and minimum Met Requirements were determined by measuring the oxidation of l-[1-13C]Phe to 13CO2 (F13CO2). A 2-phase linear-regression crossover analysis of the F13CO2 data identified a breakpoint at minimal F13CO2 Urine samples collected from all study days and from previous studies of healthy children were measured for sulfur metabolites.Results: The mean and population-safe (upper 95% CI) intakes of TSAA and minimum Met in children with CRI were determined to be 12.6 and 15.9 mg · kg-1 · d-1 and 7.3 and 10.9 mg · kg-1 · d-1, respectively. In healthy school-aged children the mean and upper 95% CI intakes of TSAA and minimum Met were determined to be 12.9 and 17.2 mg · kg-1 · d-1 and 5.8 and 7.3 mg · kg-1 · d-1, respectively. A comparison of the minimum Met Requirements between healthy children and children with CRI indicated significant (P < 0.05) differences.Conclusion: These results suggest that children with CRI have a similar mean and population-safe TSAA to that of healthy children, suggesting adequate Cys synthesis via transsulfuration, but higher minimum Met requirement, suggesting reduced remethylation rates.
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recent advances in determining protein and Amino Acid Requirements in humans
British Journal of Nutrition, 2012Co-Authors: Rajavel Elango, Ronald O. Ball, Paul B. PencharzAbstract:During the past 25 years a significant amount of research has been conducted to determine Amino Acid Requirements in humans. This is primarily due to advancements in the application of stable isotopes to examine Amino Acid Requirements. The indicator Amino Acid oxidation (IAAO) method has emerged as a robust and minimally invasive technique to identify Requirements. The IAAO method is based on the concept that when one indispensable dietary Amino Acid (IDAA) is deficient for protein synthesis, then the excess of all other IDAA, including the indicator Amino Acid, will be oxidized. With increasing intakes of the limiting Amino Acid, IAAO will decrease, reflecting increasing incorporation into protein. Once the requirement for the limiting Amino Acid is met there will be no further change in the indicator oxidation. The IAAO method has been systematically applied to determine most IDAA Requirements in adults. The estimates are comparable to the values obtained using the more elaborate 24h-indicator Amino Acid oxidation and balance (24h-IAAO/IAAB) model. Due to its non-invasive nature the IAAO method has also been used to determine Requirements for Amino Acids in neonates, children and in disease. The IAAO model has recently been applied to determine total protein Requirements in humans. The IAAO method is rapid, reliable and has been used to determine Amino Acid Requirements in different species, across the life cycle and in disease. The recent application of IAAO to determine protein Requirements in humans is novel and has significant implications for dietary protein intake recommendations globally.
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indicator Amino Acid oxidation is not affected by period of adaptation to a wide range of lysine intake in healthy young men
Journal of Nutrition, 2009Co-Authors: Rajavel Elango, Ronald O. Ball, Mohammad A Humayun, Paul B. PencharzAbstract:The number of days of adaptation to a specific Amino Acid intake required prior to the determination of Amino Acid Requirements using the indicator Amino Acid oxidation method (IAAO) is still in debate. In this study, our objective was to determine whether adaptation for 8 h, 3 d, and 7 d to a wide range of lysine intakes had any effect on the oxidation of the indicator Amino Acid, l-[1-(13)C]phenylalanine, to (13)CO(2) (F(13)CO(2)). Five healthy young men randomly received each of 4 levels of lysine (5, 20, 35, and 70 mg x kg(-1) x d(-1)) along with an Amino Acid mixture to achieve a protein intake of 1.0 g x kg(-1) x d(-1) and energy intake of 1.5x resting energy expenditure during 4 separate 7-d study periods. IAAO studies were conducted on d 1, 3, and 7. During each study day, oral consumption of l-[1-(13)C]phenylalanine was followed by collection of breath for F(13)CO(2) and plasma for measurement of phenylalanine enrichment. F(13)CO(2) was affected by lysine intake but did not differ among adaptation periods of 8 h, 3 d, or 7 d. Phenylalanine flux was not significantly affected by period of adaptation. These results suggest that the minimally invasive IAAO model, where participants are adapted prior to protein intake for 2 d followed by study day adaptation to the test Amino Acid intake for 8 h, may be sufficient to estimate individual Amino Acid Requirements in healthy young men.
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Amino Acid Requirements in humans: with a special emphasis on the metabolic availability of Amino Acids
Amino Acids, 2009Co-Authors: Rajavel Elango, Ronald O. Ball, Paul B. PencharzAbstract:Due to advances made in the development of stable isotope based carbon oxidation methods, the determination of Amino Acid Requirements in humans has been an active area of research for the past 2 decades. The indicator Amino Acid oxidation (IAAO) method developed in our laboratory for humans has been systematically applied to determine almost all indispensable Amino Acid Requirements in adult humans. Nutritional application of experimentally derived Amino Acid requirement estimates depends upon the capacity of food proteins to meet the Amino Acid Requirements in humans. Therefore, there is a need to know the proportion of dietary Amino Acids which are bioavailable, or metabolically available to the body for protein synthesis following digestion and absorption. Although this concept is widely applied in animal nutrition, it has not been applied to human nutrition due to lack of data. We developed a new in vivo method in growing pigs to identify the metabolic availability of Amino Acids in foods using the IAAO concept. This metabolic availability method has recently been adapted for use in humans. As this newly developed IAAO based method to determine metabolic availability of Amino Acids in foods is suitable for rapid and routine analysis in humans, it is a major step forward in defining the protein quality of food sources and integrating Amino Acid requirement data with dietary Amino Acid availability of foods.
Ronald O. Ball - One of the best experts on this subject based on the ideXlab platform.
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dietary aromatic Amino Acid Requirements during early and late gestation in healthy pregnant women
Journal of Nutrition, 2020Co-Authors: Madeleine Ennis, Ronald O. Ball, Paul B. Pencharz, Annajoy Ong, Kenneth Lim, Glenda Courtneymartin, Rajavel ElangoAbstract:Background Phenylalanine and tyrosine (referred to as total aromatic Amino Acids; TAAs) are essential for protein synthesis, and are precursors for important catecholamines. Current estimated average requirement (EAR) recommendations for TAA during pregnancy are 36 mg·kg-1·d-1, and has not been experimentally determined. Objectives The aim was to determine TAA Requirements (dietary phenylalanine in the absence of tyrosine) during early and late gestation using the indicator Amino Acid oxidation (IAAO, with L-[1-13C]leucine) technique. Methods Nineteen healthy pregnant women (age 22-38 y) were studied at a range of phenylalanine intakes (5 to 100 mg·kg-1·d-1) in early (13-19 wk) and/or late (33-39 wk) pregnancy for a total of 51 study days. Graded test intakes were provided as 8 hourly isonitrogenous and isocaloric meals. Breath samples were collected for 13C enrichment analysis on an isotope ratio mass spectrometer. A plasma sample was collected and analyzed for phenylalanine and tyrosine concentrations on an Amino Acid analyzer. The TAA requirement in early and late pregnancy was calculated using 2-phase linear regression crossover analysis that identified breakpoints in 13CO2 production (the requirement) in response to phenylalanine intakes. Results TAA requirement during early pregnancy was 44 mg·kg-1·d-1 (95% CI: 28.3, 58.8) and during late pregnancy was 50 mg·kg-1·d-1 (95% CI: 36.1, 63.1). In early and late pregnancy, plasma phenylalanine and tyrosine concentrations rose linearly in response to graded phenylalanine intakes. Conclusions Our results suggest that the current EAR of 36 mg·kg-1·d-1 for TAAs is underestimated. When compared with results previously determined in nonpregnant adults, early pregnancy Requirements were similar (43 compared with 44 mg·kg-1·d-1, respectively). During late pregnancy, a 14% higher TAA requirement was observed when compared with early pregnancy. The results from this study have potential implications for creating gestation stage-specific TAA recommendations.
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total sulfur Amino Acid Requirements are not altered in children with chronic renal insufficiency but minimum methionine needs are increased
Journal of Nutrition, 2017Co-Authors: Rajavel Elango, Ronald O. Ball, Mahroukh Rafii, Mohammad A Humayun, Justine M Turner, Veronika Langos, Paul B. PencharzAbstract:Background: The total sulfur Amino Acid (TSAA) and minimum Met Requirements have been previously determined in healthy children. TSAA metabolism is altered in kidney disease. Whether TSAA Requirements are altered in children with chronic renal insufficiency (CRI) is unknown.Objective: We sought to determine the TSAA (Met in the absence of Cys) Requirements and minimum Met (in the presence of excess Cys) Requirements in children with CRI.Methods: Five children (4 boys, 1 girl) aged 10 ± 2.6 y with CRI were randomly assigned to receive graded intakes of Met (0, 5, 10, 15, 25, and 35 mg · kg-1 · d-1) with no Cys in the diet. Four of the children (3 boys, 1 girl) were then randomly assigned to receive graded dietary intakes of Met (0, 2.5, 5, 7.5, 10, and 15 mg · kg-1 · d-1) with 21 mg · kg-1 · d-1 Cys. The mean TSAA and minimum Met Requirements were determined by measuring the oxidation of l-[1-13C]Phe to 13CO2 (F13CO2). A 2-phase linear-regression crossover analysis of the F13CO2 data identified a breakpoint at minimal F13CO2 Urine samples collected from all study days and from previous studies of healthy children were measured for sulfur metabolites.Results: The mean and population-safe (upper 95% CI) intakes of TSAA and minimum Met in children with CRI were determined to be 12.6 and 15.9 mg · kg-1 · d-1 and 7.3 and 10.9 mg · kg-1 · d-1, respectively. In healthy school-aged children the mean and upper 95% CI intakes of TSAA and minimum Met were determined to be 12.9 and 17.2 mg · kg-1 · d-1 and 5.8 and 7.3 mg · kg-1 · d-1, respectively. A comparison of the minimum Met Requirements between healthy children and children with CRI indicated significant (P < 0.05) differences.Conclusion: These results suggest that children with CRI have a similar mean and population-safe TSAA to that of healthy children, suggesting adequate Cys synthesis via transsulfuration, but higher minimum Met requirement, suggesting reduced remethylation rates.
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protein and Amino Acid Requirements during pregnancy
Advances in Nutrition, 2016Co-Authors: Rajavel Elango, Ronald O. BallAbstract:Protein forms an essential component of a healthy diet in humans to support both growth and maintenance. During pregnancy, an exceptional stage of life defined by rapid growth and development, adequate dietary protein is crucial to ensure a healthy outcome. Protein deposition in maternal and fetal tissues increases throughout pregnancy, with most occurring during the third trimester. Dietary protein intake recommendations are based on factorial estimates because the traditional method of determining protein Requirements, nitrogen balance, is invasive and undesirable during pregnancy. The current Estimated Average Requirement and RDA recommendations of 0.88 and 1.1 g · kg(-1) · d(-1), respectively, are for all stages of pregnancy. The single recommendation does not take into account the changing needs during different stages of pregnancy. Recently, with the use of the minimally invasive indicator Amino Acid oxidation method, we defined the Requirements to be, on average, 1.2 and 1.52 g · kg(-1) · d(-1) during early (∼16 wk) and late (∼36 wk) stages of pregnancy, respectively. Although the Requirements are substantially higher than current recommendations, our values are ∼14-18% of total energy and fit within the Acceptable Macronutrient Distribution Range. Using swine as an animal model we showed that the Requirements for several indispensable Amino Acids increase dramatically during late gestation compared with early gestation. Additional studies should be conducted during pregnancy to confirm the newly determined protein Requirements and to determine the indispensable Amino Acid Requirements during pregnancy in humans.
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recent advances in determining protein and Amino Acid Requirements in humans
British Journal of Nutrition, 2012Co-Authors: Rajavel Elango, Ronald O. Ball, Paul B. PencharzAbstract:During the past 25 years a significant amount of research has been conducted to determine Amino Acid Requirements in humans. This is primarily due to advancements in the application of stable isotopes to examine Amino Acid Requirements. The indicator Amino Acid oxidation (IAAO) method has emerged as a robust and minimally invasive technique to identify Requirements. The IAAO method is based on the concept that when one indispensable dietary Amino Acid (IDAA) is deficient for protein synthesis, then the excess of all other IDAA, including the indicator Amino Acid, will be oxidized. With increasing intakes of the limiting Amino Acid, IAAO will decrease, reflecting increasing incorporation into protein. Once the requirement for the limiting Amino Acid is met there will be no further change in the indicator oxidation. The IAAO method has been systematically applied to determine most IDAA Requirements in adults. The estimates are comparable to the values obtained using the more elaborate 24h-indicator Amino Acid oxidation and balance (24h-IAAO/IAAB) model. Due to its non-invasive nature the IAAO method has also been used to determine Requirements for Amino Acids in neonates, children and in disease. The IAAO model has recently been applied to determine total protein Requirements in humans. The IAAO method is rapid, reliable and has been used to determine Amino Acid Requirements in different species, across the life cycle and in disease. The recent application of IAAO to determine protein Requirements in humans is novel and has significant implications for dietary protein intake recommendations globally.
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new energy and Amino Acid Requirements for gestating sows
Banff Pork Seminar Proceedings 2011, 2011Co-Authors: Soenke Moehn, Danilo J Franco, Crystal L Levesque, Ryan S Samuel, Ronald O. BallAbstract:In the last few years, our new research in sow nutrition has provided evidence that the feeding regimen of gestating sows needs revision. In particular, the change of Amino Acid Requirements from early to late gestation and the energy deficit of young sows in late gestation give a strong indication that phase feeding of pregnant sows may be of advantage. This paper will review recent research, introduce future perspectives in sow nutrition and suggest options for feeding strategies for sows.
Maria Teresa Dinis - One of the best experts on this subject based on the ideXlab platform.
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stress response and changes in Amino Acid Requirements in senegalese sole solea senegalensis kaup 1858
Amino Acids, 2008Co-Authors: Claudia Aragao, Joana Cortereal, Benjamin Costas, Maria Teresa Dinis, Luis E C ConceicaoAbstract:Fish in aquaculture are often exposed to various stressors that may change their ability to survive or limit growth. Amino Acids are used for processes other than growth, including stress response. This study intended to analyse how repeated acute handling stress can affect growth and Amino Acid Requirements in fish. Senegalese sole juveniles were weekly held in the air during 3 min (Handling) for 9 weeks; Control groups were left undisturbed. Growth and plasma levels of stress indicators and of free Amino Acids were assessed at the end of the experiment. Plasma cortisol and osmolality levels showed that fish in the Handling treatment were stressed, but growth was unaffected. Plasma Amino Acid concentrations indicate that their Requirements in stressed fish were altered, which probably reflects the synthesis of proteins or other specific compounds related to stress response.
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estimated Amino Acid Requirements during early ontogeny in fish with different life styles gilthead seabream sparus aurata and senegalese sole solea senegalensis
Aquaculture, 2004Co-Authors: Claudia Aragao, Luis E C Conceicao, H J Fyhn, Maria Teresa DinisAbstract:Little is known about the Amino Acid (AA) Requirements of larval fish and their possible ontogenetic changes. This paper aims to contribute to the study of these Requirements in two common cultured species in Southern Europe: gilthead seabream (Sparus aurata) and Senegalese sole (Solea senegalensis). Moreover, it is intended to identify possible dietary AA imbalances occurring in normal hatchery conditions for both species. Fish larvae were reared following standard procedures and the normal feeding schemes used in hatcheries, which includes the use of live prey for several weeks. The experiments were finished once the fish were adapted to a dry feed. Samples were collected at different points for dry weight, total protein, and AA analysis. The A/E ratios [each indispensable AA content×(total indispensable AA content including cysteine and tyrosine)−1×1000] of fish and food were compared to identify possible dietary AA imbalances. The AA profile of both fish species changed during ontogeny, but was more stable during seabream than Senegalese sole development. This is probably linked to the marked metamorphosis observed in sole. These changes in fish larval AA profile suggest that the AA Requirements change during seabream and Senegalese sole ontogenesis. Several dietary AA deficiencies were found during the ontogenetic development of both species. These deficiencies result from ontogenetic changes in the fish AA profile, but also from differences in the AA composition of the different food items. These results suggest that both the live food (rotifers and Artemia at different developmental stages) and the dry feed used in the rearing of gilthead seabream and Senegalese sole does not have an AA profile that entirely meets the Requirements for the early stages of these species.
Claudia Aragao - One of the best experts on this subject based on the ideXlab platform.
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stress response and changes in Amino Acid Requirements in senegalese sole solea senegalensis kaup 1858
Amino Acids, 2008Co-Authors: Claudia Aragao, Joana Cortereal, Benjamin Costas, Maria Teresa Dinis, Luis E C ConceicaoAbstract:Fish in aquaculture are often exposed to various stressors that may change their ability to survive or limit growth. Amino Acids are used for processes other than growth, including stress response. This study intended to analyse how repeated acute handling stress can affect growth and Amino Acid Requirements in fish. Senegalese sole juveniles were weekly held in the air during 3 min (Handling) for 9 weeks; Control groups were left undisturbed. Growth and plasma levels of stress indicators and of free Amino Acids were assessed at the end of the experiment. Plasma cortisol and osmolality levels showed that fish in the Handling treatment were stressed, but growth was unaffected. Plasma Amino Acid concentrations indicate that their Requirements in stressed fish were altered, which probably reflects the synthesis of proteins or other specific compounds related to stress response.
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estimated Amino Acid Requirements during early ontogeny in fish with different life styles gilthead seabream sparus aurata and senegalese sole solea senegalensis
Aquaculture, 2004Co-Authors: Claudia Aragao, Luis E C Conceicao, H J Fyhn, Maria Teresa DinisAbstract:Little is known about the Amino Acid (AA) Requirements of larval fish and their possible ontogenetic changes. This paper aims to contribute to the study of these Requirements in two common cultured species in Southern Europe: gilthead seabream (Sparus aurata) and Senegalese sole (Solea senegalensis). Moreover, it is intended to identify possible dietary AA imbalances occurring in normal hatchery conditions for both species. Fish larvae were reared following standard procedures and the normal feeding schemes used in hatcheries, which includes the use of live prey for several weeks. The experiments were finished once the fish were adapted to a dry feed. Samples were collected at different points for dry weight, total protein, and AA analysis. The A/E ratios [each indispensable AA content×(total indispensable AA content including cysteine and tyrosine)−1×1000] of fish and food were compared to identify possible dietary AA imbalances. The AA profile of both fish species changed during ontogeny, but was more stable during seabream than Senegalese sole development. This is probably linked to the marked metamorphosis observed in sole. These changes in fish larval AA profile suggest that the AA Requirements change during seabream and Senegalese sole ontogenesis. Several dietary AA deficiencies were found during the ontogenetic development of both species. These deficiencies result from ontogenetic changes in the fish AA profile, but also from differences in the AA composition of the different food items. These results suggest that both the live food (rotifers and Artemia at different developmental stages) and the dry feed used in the rearing of gilthead seabream and Senegalese sole does not have an AA profile that entirely meets the Requirements for the early stages of these species.