PSX-A-17 Late-Breaking: Methionine and total sulfur amino acid requirements for pups (>14 wk to 9 months), adults, and senior Labrador Retrievers using the indicator amino acid oxidation (IAAO) technique

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 374-374
Author(s):  
Jessica L Varney ◽  
Charlene Watson ◽  
Nicole Colopy ◽  
John Moss ◽  
Jordan T Weil ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Control Diet ◽  
Age Groups ◽  
Isotope Ratio Mass Spectrometry ◽  
Co2 Production ◽  
Acid Oxidation ◽  
Total Sulfur ◽  
Amino Acid Oxidation ◽  
Labrador Retrievers

Abstract Methionine and cystine are often considered limiting amino acids in canine diets but limited requirement studies have been conducted especially for different life stages. Eighteen Labrador Retrievers (6 pups (>14 wk-9 month), 6 adults, and 6 seniors [>8yr)] were utilized in feeding studies to evaluate the changing requirements of methionine (Met) and total sulfur amino acids (TSAA) as canines age. For this study, the indicator amino acid oxidation (IAAO) technique was utilized to determine the amino acid (AA) requirements in each of the three age groups. Dogs were subjected to diets ranging from deficient to excess, with indispensable amino acids formulated at 1.6x NRC values. To allow for adaptation, a control diet with same dietary ingredients, protein and amino acid levels was fed for two days prior to feeding the test diets on the third day. On test day, a baseline breath sample was collected for determining CO2 production using a respiration mask (Oxymax, Columbus Instruments). A priming dose of L-[1-13C] phenylalanine (Cambridge Isotope Laboratories, Inc.) based on body weight was utilized, followed by [1-13C] Phe doses every 30 minutes, spanning a four hour period. After each dose 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a piecewise model of best fit (JMP® Pro 16). A segmented line regression showed Met and TSAA mean and population requirements for pups (>14 wk-9 mo.) were 0.78 ± 0.16 and 1.53 ± 0.21 g/1000kcal (mean ± 2SD), respectively. Meanwhile, for adults, mean and population requirements for Met and TSAA were estimated to be 0.68 ± 0.19 and 1.4 ± 0.30 g/1000kcal (mean ± 2SD), respectively, and for seniors, Met and TSAA mean and population requirements were determined to be 0.62 ± 0.17 and 1.27 ± 0.23 g/1000kcal (mean ± 2SD), respectively.

scholarly journals PSVI-30 Requirements of the sulfur amino acids in growing Labrador Retrievers using the indicator amino acid oxidation technique

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 312-312
Author(s):  
Jordan T Weil ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Craig N Coon
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Control Diet ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Oxidation ◽  
Sulfur Amino Acids ◽  
Amino Acid Oxidation ◽  
Amino Acid Requirements ◽  
Indispensable Amino Acids ◽  
Labrador Retrievers

Abstract Over time, the need to update amino acid (AA) requirements for canines becomes increasingly important to ensure animals are healthy and free of nutritional disease. Each of the AA plays a crucial role in the metabolism and health of mammals. Of the essential AA, the total sulfur amino acids (TSAA), namely methionine (Met) and cysteine (Cys), are involved in metabolic functions such as protein metabolism, intestinal health, and urinary function. Additionally, Met can function as a precursor in the requirement of Cys. The purpose of this experiment was to use the indicator amino acid oxidation technique to determine amino acid requirements on growing Labrador Retrievers. A total of 12 dogs were subjected to 12 diets with varying levels of Met and Cys, ranging from deficient to excess. Diets were formulated to 1.6x NRC values for all indispensable amino acids. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a broken line model (JMP® Pro 15). Results showed that the Met and TSAA mean and population requirements were 0.78 ± 0.16 and 1.53 ± 0.21 g/1000kcal (mean ± 2SD), respectively. Knowledge gained from these studies is necessary as the petfood industry aims to deliver accurate diet formulations to the expansive canine population.

scholarly journals PSXI-31 Program Chair Poster Pick: Determination of the threonine requirement in adult and senior Labrador Retrievers using the indicator amino acid oxidation technique

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 321-322
Author(s):  
Jordan T Weil ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Craig N Coon
Keyword(s):  
Amino Acid ◽  
Control Diet ◽  
Genetic Selection ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Oxidation ◽  
Amino Acid Oxidation ◽  
Amino Acid Requirements ◽  
Indispensable Amino Acids ◽  
Nutrient Profiles ◽  
Labrador Retrievers

Abstract Although nutrient profiles for canines have been developed in the past, the need to update amino acid (AA) requirements has gained importance as genetic selection changes the recommended nutrients. Correctly feeding AA to canines can have enormous effects, considering a deficiency or excess of such nutrient can lead to weight loss, disease, or in some cases, death. Amino acid requirements can be determined through the nitrogen balance or indicator amino acid oxidation (IAAO) methods. In this experiment, the IAAO technique was used to determine the threonine (Thr) requirement in Labrador retrievers. A total of six dogs (6 adult and 6 senior) were subjected to six diets with varying levels of Thr, ranging from deficient to excess. Diets were formulated to 1.6x NRC values for all indispensable amino acids. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer AA was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a piecewise model of best fit (JMP® Pro 15). The segmented line regression showed that the Thr mean and population requirements were determined to be 1.21 ± 0.24 and 0.92 ± 0.17 g/1000kcal (mean ± 2SD) for adult and senior dogs, respectively. As the pet food industry becomes more specialized in diets relating to aging, and diseased canines, updating the amino acid requirements related to such animals is increasingly important.

scholarly journals 236 Determination of amino acid requirements of lysine and tryptophan of >14 wk old growing Labrador retriever puppies using the indicator amino acid oxidation technique

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 59-60
Author(s):  
Craig N Coon ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Jordan T Weil ◽  
Mary Ann Boggess
Keyword(s):  
Amino Acid ◽  
Control Diet ◽  
Age Groups ◽  
Isotope Ratio Mass Spectrometry ◽  
Labrador Retriever ◽  
Acid Oxidation ◽  
Amino Acid Oxidation ◽  
Amino Acid Requirements ◽  
Nutrient Profiles

Abstract As the pet food industry develops products aimed to supply the nutrients necessary for the wellness and longevity of canines, it is important to understand the amino acid requirements needed for such health and growth. In this experiment, a total of six growing Labrador retriever puppies were studied during each testing period in order to determine their individual amino acid requirements through the indicator amino acid oxidation (IAAO) technique. To do this, the puppies were supplied with constant dietary Phe in the control and test diets. Excluding the control diet, a total of six diets with varying levels of the amino acid of interest were utilized in this experiment. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a broken-line model of best fit (JMP Pro 14.1). Through the segmented line regression of 13Phe oxidation, it was shown that lysine and tryptophan mean requirements were 0.627 and 0.204%, respectively. A 95% confidence interval was calculated as 0.627 ± 0.180 and 0.204 ± 0.182% (mean ± 2SD) for lysine and tryptophan, respectively, representing the population’s safe requirements. The determination of the amino acid requirements found in this study proves useful as the industry develops nutrient profiles specific to the needs of varying age groups and growing Labradors.

scholarly journals PSIV-B-29 Late-Breaking: Evaluation of arginine requirements of growing > 14 week to 9 month old Labrador retrievers using differing diet formulations and the indicator amino acid oxidation technique

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 321-321
Author(s):  
Craig N Coon ◽  
Jessica L Varney ◽  
Jordan T Weil ◽  
Jason W Fowler ◽  
Mary Ann Boggess
Keyword(s):  
Amino Acid ◽  
Control Diet ◽  
Genetic Selection ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Oxidation ◽  
Amino Acid Oxidation ◽  
Group I ◽  
Amino Acid Requirements ◽  
Group 2 ◽  
Labrador Retrievers

Abstract Over time, the need to update amino acid requirements for canines is increasingly important due to genetic selection and the demand for more advanced diets. Amino acid requirements can be determined through differing methods including, but not limited to, nitrogen balance studies and the indicator amino acid oxidation (IAAO) technique. In this study, the IAAO method was studied on a total of six growing Labrador Retrievers to determine their individual amino acid requirements. Twelve test diets with varying levels of Arg were utilized to conduct this experiment. Six diets contained excess Lys with respect to Arg (Group 1), while the remaining diets contained lower Lys inclusions (Group 2). Diets were formulated to 1.6x NRC values for all indispensable amino acids, including Lys. Group 2 diet formulations were formulated the same as Group I, except the test Lys was set at 0.1% above test Arg levels. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a piecewise model of best fit (JMP Pro 14.1). Through the segmented line regression, the arginine mean requirement and population safe requirements of growing dogs in Groups 1 and 2 was found to be 1.49 ± 0.30 and 1.38 ± 0.21 g/1000 kcal ME (mean ± 2SD), respectively.

scholarly journals PSI-B-40 Late-Breaking: Determination of lysine requirements of young and senior Labrador retrievers using the indicator amino acid oxidation technique

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 317-317
Author(s):  
Jessica L Varney ◽  
Jordan T Weil ◽  
Jason W Fowler ◽  
Craig N Coon
Keyword(s):  
Amino Acid ◽  
Control Diet ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Oxidation ◽  
Amino Acid Oxidation ◽  
Aging Populations ◽  
Amino Acid Requirements ◽  
Labrador Retrievers ◽  
Best Fit

Abstract In order improve the health and longevity of canines, the need to determine amino acid requirements for aging populations is particularly important. In this experiment, a total of six young (< 1.5 yrs) and six old (>8 yrs) Labrador retrievers were studied in order to determine the lysine (Lys) requirement through the indicator amino acid oxidation (IAAO) technique. All dogs were supplied with constant dietary Phe in the control and test diets. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was first supplied, followed by [1-13C]Phe doses every thirty minutes, spanning a four hour period. A respiration mask was placed on each subject every thirty minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a broken-line model of best fit (JMP Pro 14.1). The [1-13C] Phe oxidation results showed that the minimal requirement of the young adult and senior dogs was 1.08 ± 0.59 and 0.83 ± 0.12 (mean ± 2SD) g/1000 kcal ME, respectively. The lower lysine requirements for the senior dogs is due to the seniors having an average of 987g less lean mass per dog than the young adults.

PSX-A-5 Late-Breaking: Branched chain amino acid and threonine requirements for puppy (>14 wk-9mo) Labrador Retrievers using the indicator amino acid oxidation (IAAO) technique

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 363-364
Author(s):  
Jessica L Varney ◽  
Heather Adams ◽  
Sarah Cox ◽  
Kevin Cline ◽  
Rhianna Bailey ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Control Diet ◽  
Branched Chain Amino Acids ◽  
Acid Oxidation ◽  
Gut Health ◽  
Isoleucine Leucine ◽  
Amino Acid Oxidation ◽  
Branched Chain ◽  
Labrador Retrievers

Abstract Branched chain amino acids are heavily involved in protein synthesis and turnover, emphasizing the need to establish requirement for growing animals. On the other hand, threonine is vital for supporting proteins necessary for gut health. Thus, it is very important to supply branched chain amino acids and threonine in appropriate amounts to growing animals. In this experiment, the indicator amino acid oxidation (IAAO) technique was utilized to determine valine, isoleucine, leucine, and threonine requirements in six puppy Labrador Retrievers (>14wk-9mo). Puppies were subjected to diets ranging from deficient to excess, with each of the indispensable amino acids formulated at 1.6x NRC values. The control diet was fed for two days of adaptation, followed by one experimental day in which the test diet was fed. On the test day, a breath sample was collected using a using a respiration mask (Oxymax, Columbus Instruments). A priming dose of L-[1-^13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on body weight was supplied to each puppy, followed by [1-^13C]Phe doses every 30 minutes, for a four hour period. ^13CO[2] was collected after each dose and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results from IRMS were converted to atom percent excess (APE) and analyzed using a segmented line model (JMP^® Pro 16). Each of the Four Rivers mean and population requirements were as follows: 1.72 ± 0.11 g/1000 kcal ME for valine; 1.43 ± 0.24 g/1000 kcal ME for isoleucine; 2.25 ± 0.15 g/1000 kcal ME for leucine; 1.74 ± 0.16 g/1000 kcal ME for threonine (mean ± 2SD). The knowledge gained from this study is highly useful as the lean mass deposited as a puppy influences the animal throughout their lifetime.

scholarly journals PSXI-34 Evaluating the lysine requirements of adult and senior Labrador Retrievers using low and high crude protein inclusion levels

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 322-322
Author(s):  
Jordan T Weil ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Craig N Coon
Keyword(s):  
Amino Acid ◽  
Crude Protein ◽  
Control Diet ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Oxidation ◽  
Body Tissues ◽  
Labrador Retrievers ◽  
Best Fit ◽  
Atom Percent Excess

Abstract Despite consumer interest in senior pet care, little is known about the effect of changing crude protein (CP) levels on the lysine (Lys) requirements in young and senior dogs. Feeding crude protein in excess can lead to long-term health problems. Moreover, changing the CP content of the diet can lead differences in Lys requirements. Two experiments were conducted to determine the Lys requirements in adult and senior Labrador Retrievers through the indicator amino acid oxidation technique. Six young (< 1.5 yrs) and six old (>8 yrs) dogs were allocated to two trials (6 dogs/exp) to determine the effects of feeding 13 and 18% CP on the Lys requirement. All dogs were supplied with constant dietary Phe across diets. The control diet was fed for two days, followed by a day in which the test diet was fed, a tracer amino acid was supplied, and breath samples were collected. On test day, a priming dose of L-[1-13C]phenylalanine (Cambridge Isotope Laboratories, Inc.) based on the subject’s body weight was supplied, followed by [1-13C]Phe doses every 30 minutes, spanning a four hour period. A respiration mask was placed on each subject every 30 minutes (Oxymax, Columbus Instruments), 13CO2 was collected, and enrichment was determined by isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using a broken-line model of best fit (JMP® Pro 15). Oxidation results showed that for a 13% CP diet, the Lys mean and population safe requirements (mean±2SD) were 1.56±0.25 and 0.81±0.37 g/1000kcal for adult and senior dogs, respectively. For the 18% CP diet, adult and senior dog mean and population safe requirements were 1.36±0.18 and 0.86±0.07 g/1000kcal accordingly. The results suggest that as dogs age, the lowered lean mass requires less AA nitrogen and Lys to maintain body tissues.

scholarly journals Adult dogs of different breed sizes have similar threonine requirements as determined by the indicator amino acid oxidation technique

2020 ◽  
Vol 98 (3) ◽  
Author(s):  
Wilfredo D Mansilla ◽  
Lisa Fortener ◽  
James R Templeman ◽  
Anna K Shoveller
Keyword(s):  
Amino Acid ◽  
Basal Diet ◽  
Acid Oxidation ◽  
Total Production ◽  
Experimental Diet ◽  
Two Phase ◽  
Deficient Diet ◽  
Amino Acid Oxidation ◽  
The Mean ◽  
Labrador Retrievers

Abstract Threonine (Thr) requirements for immature (growing) Beagles have been determined, but little knowledge is available on Thr requirements for maintenance in mature dogs. Moreover, differences of Thr requirements among different breeds or sizes of adult dogs have not been investigated. The objective of the present study was to determine Thr requirements in adult dogs of three different breeds using the indicator amino acid oxidation (IAAO) technique. In total, 13 adult dogs were used, 4 Miniature Dachshunds (5.8 ± 0.4 kg body weight [BW]; 3 spayed and 1 neutered), 4 spayed Beagles (9.3 ± 0.6 kg BW), and 5 neutered Labrador Retrievers (30.5 ± 1.7 kg BW). Dogs were fed a Thr-deficient diet (Thr = 0.23%) and randomly allocated to receiving one of seven concentrations of Thr supplementation (final Thr concentration in experimental diets was 0.23%, 0.33%, 0.43%, 0.53%, 0.63%, 0.73%, and 0.83%; as fed basis) for 2 d. After 2 d of adaptation to the experimental diets, dogs underwent individual IAAO studies. During the IAAO studies, total daily feed was divided into 13 equal meals; at the sixth meal, dogs were fed a bolus of l-[1-13C]-Phenylalanine (Phe) (9.40 mg/kg BW), and thereafter, l-[1-13C]-Phe (2.4 mg/kg BW) was supplied with every meal. Before feeding the next experimental diet, dogs were fed a Thr-adequate basal diet for 4 d (Thr = 0.80% as fed basis) in known amounts that maintained individual dog BW. Total production of 13CO2 during isotopic steady state was determined by enrichment of 13CO2 in breath samples and total production of CO2 measured using indirect calorimetry. The mean requirements for Thr, defined as the breakpoint, and the 95% confidence interval (CI) were determined using a two-phase linear regression model. For Miniature Dachshunds, the two-phase model was not significant, and Thr requirements could not be determined. Mean Thr requirements for Beagles and Labradors were 72.2 and 64.1 mg/kg BW on an as-fed basis, respectively. The requirement for Thr between these two dog breeds was not different (P > 0.10). Thus, the data for Beagles and Labradors were pooled and a mean requirement for Thr was determined at 66.9 mg/kg BW, and the 95% CI was estimated at 84.3 mg/kg BW. In conclusion, estimated Thr requirements for Beagles and Labradors did not differ, and these recommendations are higher than those suggested by NRC (2006) and AAFCO (2014) for adult dogs at maintenance.

Quantitative analysis of amino acid oxidation and related gluconeogenesis in humans

1992 ◽  
Vol 72 (2) ◽  
pp. 419-448 ◽  
Author(s):  
R. L. Jungas ◽  
M. L. Halperin ◽  
J. T. Brosnan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Urea Cycle ◽  
Liver Mitochondria ◽  
Carbon Flow ◽  
Acid Oxidation ◽  
Peripheral Tissues ◽  
Amino Acid Oxidation ◽  
Atp Production ◽  
Acid Load

Significant gaps remain in our knowledge of the pathways of amino acid catabolism in humans. Further quantitative data describing amino acid metabolism in the kidney are especially needed as are further details concerning the pathways utilized for certain amino acids in liver. Sufficient data do exist to allow a broad picture of the overall process of amino acid oxidation to be developed along with approximate quantitative assessments of the role played by liver, muscle, kidney, and small intestine. Our analysis indicates that amino acids are the major fuel of liver, i.e., their oxidative conversion to glucose accounts for about one-half of the daily oxygen consumption of the liver, and no other fuel contributes nearly so importantly. The daily supply of amino acids provided in the diet cannot be totally oxidized to CO2 in the liver because such a process would provide far more ATP than the liver could utilize. Instead, most amino acids are oxidatively converted to glucose. This results in an overall ATP production during amino acid oxidation very nearly equal to the ATP required to convert amino acid carbon to glucose. Thus gluconeogenesis occurs without either a need for ATP from other fuels or an excessive ATP production that could limit the maximal rate of the process. The net effect of the oxidation of amino acids to glucose in the liver is to make nearly two-thirds of the total energy available from the oxidation of amino acids accessible to peripheral tissues, without necessitating that peripheral tissues synthesize the complex array of enzymes needed to support direct amino acid oxidation. As a balanced mixture of amino acids is oxidized in the liver, nearly all carbon from glucogenic amino acids flows into the mitochondrial aspartate pool and is actively transported out of the mitochondria via the aspartate-glutamate antiport linked to proton entry. In the cytoplasm the aspartate is converted to fumarate utilizing urea cycle enzymes; the fumarate flows via oxaloacetate to PEP and on to glucose. Thus carbon flow through the urea cycle is normally interlinked with gluconeogenic carbon flow because these metabolic pathways share a common step. Liver mitochondria experience a severe nonvolatile acid load during amino acid oxidation. It is suggested that this acid load is alleviated mainly by the respiratory chain proton pump in a form of uncoupled respiration.(ABSTRACT TRUNCATED AT 400 WORDS)

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