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 ◽  
...  

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.

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 374-374
Author(s):  
Jessica L Varney ◽  
Charlene Watson ◽  
Nicole Colopy ◽  
John Moss ◽  
Jordan T Weil ◽  
...  

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.


2004 ◽  
Vol 287 (1) ◽  
pp. E142-E149 ◽  
Author(s):  
Roya Riazi ◽  
Mahroukh Rafii ◽  
Joe T. R. Clarke ◽  
Linda J. Wykes ◽  
Ronald O. Ball ◽  
...  

Maple syrup urine disease (MSUD) is an autosomal recessive disorder caused by defects in the mitochondrial multienzyme complex branched-chain α-keto acid dehydrogenase (BCKD; EC 1.2.4.4 ), responsible for the oxidative decarboxylation of the branched-chain ketoacids (BCKA) derived from the branched-chain amino acids (BCAA) leucine, valine, and isoleucine. Deficiency of the enzyme results in increased concentrations of the BCAA and BCKA in body cells and fluids. The treatment of the disease is aimed at keeping the concentration of BCAA below the toxic concentrations, primarily by dietary restriction of BCAA intake. The objective of this study was to determine the total BCAA requirements of patients with classical MSUD caused by marked deficiency of BCKD by use of the indicator amino acid oxidation (IAAO) technique. Five MSUD patients from the MSUD clinic of The Hospital for Sick Children participated in the study. Each was randomly assigned to different intakes of BCAA mixture (0, 20, 30, 50, 60, 70, 90, 110, and 130 mg·kg−1·day−1), in which the relative proportion of BCAA was the same as that in egg protein. Total BCAA requirement was determined by measuring the oxidation of l-[1-13C]phenylalanine to 13CO2. The mean total BCAA requirement was estimated using a two-phase linear regression crossover analysis, which showed that the mean total BCAA requirement was 45 mg·kg−1·day−1, with the safe level of intake (upper 95% confidence interval) at 62 mg·kg−1·day−1. This is the first time BCAA requirements in patients with MSUD have been determined directly.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 312-312
Author(s):  
Jordan T Weil ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Craig N Coon

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.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 321-322
Author(s):  
Jordan T Weil ◽  
Jessica L Varney ◽  
Jason W Fowler ◽  
Craig N Coon

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.


1975 ◽  
Vol 148 (3) ◽  
pp. 363-374 ◽  
Author(s):  
M G Buse ◽  
S Jursinic ◽  
S S Reid

1. The oxidation of the three branched-chain amino acids was regulated in parallel fashion in rat tissues studied in vitro. 2. With 0.1 mM-[1-14C]isoleucine as substrate in the presence of 5.5 mM-glucose, 14CO2 production was 0.6 mumol/2 h per g in the aorta, 0.3 in peripheral nerve, 0.2 in muscle and 0.13 in spinal cord. 3. The ratio 14C oxidized/14C incorporated into proteins with 0.1 mM-[1-14C]leucine was 1.3 in hemidiaphragms, 3.3 in sciatic nerve and 1.0 in nerves undergoing Wallerian degeneration. Leucine oxidation decreased only slightly during degeneration, but protein synthesis doubled. 4. Hemidiaphragms incubated with [1-14C]leucine or 4-methyl-2-oxo[1-14C]pentanoate increased 14CO2 production 7-9-fold as substrate concentration was increased from 0.1 to 0.5 mM; under the same conditions 14CO2 production by nerves increased only 2-3-fold. 5. 2-Oxoglutarate stimulated the oxidation of the branched-chain amino acids by muscles and peripheral nerves and the oxidation of 4-methyl-2-oxopentanoate by hemidiaphragms but not by nerves. 6. Octanoate (0.1-1.0 mM) markedly stimulated the oxidation of branched-chain amino acids and of 4-methyl-2-oxopentanoate in hemidiaphragms, but inhibited oxidation of both by peripheral nerves and spinal cord. In aortas, oxidation of isoleucine (the only substance tested) was inhibited by octanoate. 7. The effects of octanoate and 2-oxoglutarate on leucine oxidation by hemidiaphragms were additive at low concentrations. When maximally stimulating concentrations of either agent were used, addition of the other was ineffective. 8. Pyruvate inhibited the oxidation of branched-chain amino acids and 4-methyl-2-oxopentanoate in all tissues tested. 9. Insulin did not affect the oxidation of 4-methyl-2-oxopentanoate by muscles or nerves. 10. The oxidative decarboxylation of the branched-chain alpha-oxo acids is suggested as a regulatory site of branched-chain amino acid oxidation. Differences in regulation between muscle on the one hand, and nerve and aorta on the other, are discussed.


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

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.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 317-317
Author(s):  
Jessica L Varney ◽  
Jordan T Weil ◽  
Jason W Fowler ◽  
Craig N Coon

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.


Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 95
Author(s):  
Imran Ramzan ◽  
Moira Taylor ◽  
Beth Phillips ◽  
Daniel Wilkinson ◽  
Kenneth Smith ◽  
...  

Elevated circulating branched-chain amino acids (BCAAs; isoleucine, leucine, and valine) are associated with obesity and type 2 diabetes (T2D). Reducing circulatory BCAAs by dietary restriction was suggested to mitigate these risks in rodent models, but this is a challenging paradigm to deliver in humans. We aimed to design and assess the feasibility of a diet aimed at reducing circulating BCAA concentrations in humans, while maintaining energy balance and overall energy/protein intake. Twelve healthy individuals were assigned to either a 7-day BCAA-restricted diet or a 7-day control diet. Diets were iso-nitrogenous and iso-caloric, with only BCAA levels differing between the two. The BCAA-restricted diet significantly reduced circulating BCAA concentrations by ~50% i.e., baseline 437 ± 60 to 217 ± 40 µmol/L (p < 0.005). Individually, both valine (245 ± 33 to 105 ± 23 µmol/L; p < 0.0001), and leucine (130 ± 20 to 75 ± 13 µmol/L; p < 0.05), decreased significantly in response to the BCAA-restricted diet. The BCAA-restricted diet marginally lowered Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) levels: baseline 1.5 ± 0.2 to 1.0 ± 0.1; (p = 0.096). We successfully lowered circulating BCAAs by 50% while maintaining iso-nitrogenous, iso-caloric dietary intakes, and while meeting the recommended daily allowances (RDA) for protein requirements. The present pilot study represents a novel dietary means by which to reduce BCAA, and as such, provides a blueprint for a potential dietary therapeutic in obesity/diabetes.


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