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Pezzali JG, Lambie JG, Verbrugghe A, Shoveller AK. Minimum methionine requirement in adult cats as determined by indicator amino acid oxidation. J Anim Sci 2024; 102:skad411. [PMID: 38092464 PMCID: PMC10768993 DOI: 10.1093/jas/skad411] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/12/2023] [Indexed: 01/07/2024] Open
Abstract
There is a lack of empirical data on the dietary Met requirement, in the presence of Cys or cystine, in adult cats. Thus, the aim of this study was to determine the Met requirement, in the presence of excess Cys, in adult cats at maintenance using the indicator amino acid oxidation (IAAO) technique. Six adult neutered male cats were initially selected and started the study. Cats were adapted to the basal diet sufficient in Met (0.24% dry matter, DM) for 14 d prior to being randomly allocated to one of eight dietary levels of Met (0.10%, 0.13%, 0.17%, 0.22%, 0.27%, 0.33%, 0.38%, and 0.43% DM). Different dietary Met concentrations were achieved by supplementing the basal diet with Met solutions. Alanine was additionally included in the solutions to produce isonitrogenous and isoenergetic diets. Cats underwent a 2-d adaptation period to each experimental diet prior to each IAAO study day. On IAAO study days, 13 meals were offered corresponding to 75% of each cat's daily food allowance. The remaining 25% of their daily food intake was offered after each IAAO study. A bolus dose of NaH13CO3 (0.44 mg kg-1) and l-[1-13C]-phenylalanine (13C-Phe; 4.8 mg kg-1) were provided in fifth and sixth meals, respectively, followed by a constant dose of 13C-Phe (1.04 mg kg-1) in the next meals. Breath samples were collected and total production of 13CO2 was measured every 25 min through respiration calorimetry chambers. Steady state of 13CO2 achieved over at least three breath collections was used to calculate oxidation of 13C-Phe (F13CO2). Competing models were applied using the NLMIXED procedure in SAS to determine the effects of dietary Met on 13CO2. Two cats were removed from the study as they did not eat all meals, which is required to achieve isotopic steady. A breakpoint for the mean Met requirement, with excess of Cys, was identified at 0.24% DM (22.63 mg kg-1) with an upper 95% confidence limit of 0.40% DM (37.71 mg·kg-1), on an energy density of 4,164 kcal of metabolizable energy/kg DM calculated using the modified Atwater factors. The estimated Met requirement, in the presence of excess of Cys, is higher than the current recommendations proposed by the National Research Council's Nutrient Requirement of Dogs and Cats, the Association of American Feed Control Officials, and the European Pet Food Industry Federation.
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Affiliation(s)
- Júlia Guazzelli Pezzali
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, ON, CanadaN1G 2W1
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, USA
| | - Jocelyn G Lambie
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, ON, CanadaN1G 2W1
| | - Adronie Verbrugghe
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, CanadaN1G 2W1
| | - Anna K Shoveller
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, ON, CanadaN1G 2W1
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Fahey GC, Campion M, Collings GF, Donadelli R, Lambrakis L, Panasevich MR, Peters JC, Templeman JR, Hancock L. The art of establishing mineral tolerances of dogs and cats. J Anim Sci 2024; 102:skae132. [PMID: 38850274 PMCID: PMC11161897 DOI: 10.1093/jas/skae132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 05/09/2024] [Indexed: 06/10/2024] Open
Abstract
For over six decades, nutritional science has provided well-developed, peer-reviewed nutrient recommendations to support the health of dogs and cats. These guidelines are updated based on new scientifically valid research and appropriate peer-review. Recent regulatory and scientific positions around health issues have resulted in strong opinions and desires for rapid regulatory action surrounding mineral nutrition, but with limited and conflicting scientific evidence. Pet Food Institute nutrition experts have come together to jointly author an article on the complexities of establishing mineral tolerances of dogs and cats to illustrate the limitations in defining mineral tolerances. This discussion covers how mineral requirements were determined, including the opportunities and pitfalls encountered. Scientific councils must review and clarify any proposed changes in conducting mineral nutrition research that might impact complete and balanced foods and surrounding regulations. It is important to clarify the multiple issues in mineral nutrition research and the necessity for thorough evaluation of data while avoiding arbitrary and potentially harmful guidelines.
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Affiliation(s)
- George C Fahey
- Professor Emeritus of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Marcie Campion
- Global Pet Technical Lead at Cargill Inc., Dayton, OH, USA
| | - George F Collings
- President & General Manager at Nutrition Solutions, O'Fallon, MO, USA
| | - Renan Donadelli
- Product Development Scientist at Freshpet, Bethlehem, PA, USA
| | - Leah Lambrakis
- VP R&D, Nutrition and Scientific Affairs at Simmons Pet Food, Toronto, ON, CANADA
| | | | - J C Peters
- Technical Sales Lead & Nutritionist at Cargill Inc., Brookville, OH, USA
| | - James R Templeman
- Director of Nutrition and Formulation at Primal Pet Foods, Guelph, ON, CANADA
| | - Leslie Hancock
- Chief Medical Officer, Hill's Pet Nutrition, Topeka, KS, USA
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3
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Lambie JG, Pezzali JG, Richards TL, Ellis JL, Verbrugghe A, Shoveller AK. Phenylalanine requirements using the direct amino acid oxidation technique, and the effects of dietary phenylalanine on food intake, gastric emptying, and macronutrient metabolism in adult cats. J Anim Sci 2024; 102:skae009. [PMID: 38198741 PMCID: PMC10873786 DOI: 10.1093/jas/skae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/09/2024] [Indexed: 01/12/2024] Open
Abstract
Despite Phe being an indispensable amino acid for cats, the minimum Phe requirement for adult cats has not been empirically defined. The objective of study 1 was to determine the minimum Phe requirement, where Tyr is in excess, in adult cats using the direct amino acid oxidation (DAAO) technique. Four adult male cats were used in an 8 × 4 Latin rectangle design. Cats were adapted to a basal diet for 7 d, top dressed with Phe to meet 140% of the adequate intake (NRC, 2006. Nutrient requirements of dogs and cats. Washington, DC: Natl. Acad. Press). Cats were randomly assigned to one of eight experimental Phe diets (0.29%, 0.34%, 0.39%, 0.44%, 0.54%, 0.64%, 0.74%, and 0.84% Phe in the diet on a dry matter [DM] basis). Following 1 d of diet adaptation, individual DAAO studies were performed. During each DAAO study, cats were placed into individual indirect calorimetry chambers, and 75% of the cat's daily meal was divided into 13 equal meals supplied with a dose of L-[1-13C]-Phe. Oxidation of L-[1-13C]-Phe (F13CO2) during isotopic steady state was determined from the enrichment of 13CO2 in breath. Competing models were applied using the NLMIXED procedure in SAS to determine the effects of dietary Phe on 13CO2. The mean population minimum requirement for Phe was estimated at 0.32% DM and the upper 95% population confidence limit at 0.59% DM on an energy density of 4,200 kcal of metabolizable energy/kg DM calculated using the modified Atwater factors. In study 2, the effects of a bolus dose of Phe (44 mg kg-1 BW) on food intake, gastric emptying (GE), and macronutrient metabolism were assessed in a crossover design with 12 male cats. For food intake, cats were given Phe 15 min before 120% of their daily food was offered and food intake was measured. Treatment, day, and their interaction were evaluated using PROC GLIMMIX in SAS. Treatment did not affect any food intake parameters (P > 0.05). For GE and macronutrient metabolism, cats were placed into individual indirect calorimetry chambers, received the same bolus dose of Phe, and 15 min later received 13C-octanoic acid (5 mg kg-1 BW) on 50% of their daily food intake. Breath samples were collected to measure 13CO2. The effect of treatment was evaluated using PROC GLIMMIX in SAS. Treatment did not affect total GE (P > 0.05), but cats receiving Phe tended to delay time to peak enrichment (0.05 < P ≤ 0.10). Overall, Phe at a bolus dose of 44 mg kg-1 BW had no effect on food intake, GE, or macronutrient metabolism. Together, these results suggest that the bolus dose of Phe used may not be sufficient to elicit a GE response, but a study with a greater number of cats and greater food intake is warranted.
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Affiliation(s)
- Jocelyn G Lambie
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, CanadaN1G 2W1
| | - Júlia G Pezzali
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, CanadaN1G 2W1
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506
| | - Taylor L Richards
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, CanadaN1G 2W1
| | - Jennifer L Ellis
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, CanadaN1G 2W1
| | - Adronie Verbrugghe
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Anna K Shoveller
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, CanadaN1G 2W1
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Singh P, Banton S, Bosch G, Hendriks WH, Shoveller AK. Beyond the Bowl: Understanding Amino Acid Requirements and Digestibility to Improve Protein Quality Metrics for Dog and Cat Foods. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1446:99-134. [PMID: 38625526 DOI: 10.1007/978-3-031-54192-6_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
The determination of amino acid (AA) requirements for mammals has traditionally been done through nitrogen (N) balance studies, but this technique underestimates AA requirements in adult animals. There has been a shift toward researchers using the indicator amino acid oxidation (IAAO) technique for the determination of AA requirements in humans, and recently in dogs. However, the determination of AA requirements specific to adult dogs and cats at maintenance is lacking and the current requirements outlined by the National Research Council are based on a dearth of data and are likely underreporting the requirements of indispensable AA (IAA) for the population. To ensure the physiological requirements of our cats and dogs are met, we need methods to accurately and precisely measure digestibility. In vivo methods, such as ileal cannulation, are most commonly used, however, due to ethical considerations, we are moving away from animal models and toward in vitro methods. Harmonized static digestion models have the potential to replace in vivo methods but work needs to be done to have these methods more accurately represent the gastrointestinal tract (GIT) of cats and dogs. The Digestible IAA Score (DIAAS) is one metric that can help define protein quality for individual ingredients or mixed diets that uses AA SID estimates and ideally those can be replaced with in vitro AA digestibility estimates. Finally, we need accurate and reliable laboratory AA analyses to measure the AA present in complete diets, especially those used to quantify methionine (Met) and cysteine (Cys), both often limiting AAs in cat and dog diets. Together, this will guide accurate feed formulation for our companion animals to satisfy requirements while avoiding over-supplying protein, which inevitably contributes to excess N excretion, affecting both the environment and feed sustainability.
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Affiliation(s)
- Pawanpreet Singh
- Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Sydney Banton
- Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - Guido Bosch
- Animal Nutrition Group, Wageningen University, Wageningen, The Netherlands
| | - Wouter H Hendriks
- Animal Nutrition Group, Wageningen University, Wageningen, The Netherlands
| | - Anna K Shoveller
- Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada.
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Pezzali JG, Lambie JG, Phillips SM, Shoveller AK. Determination of a steady-state isotope dilution protocol for carbon oxidation studies in the domestic cat. J Nutr Sci 2023; 12:e62. [PMID: 37313346 PMCID: PMC10260335 DOI: 10.1017/jns.2023.44] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 06/15/2023] Open
Abstract
The present study aimed to develop an isotope protocol to achieve equilibrium of 13CO2 in breath of cats during carbon oxidation studies using L-[1-13C]-Phenylalanine (L-[1-13C]-Phe), provided orally in repeated meals. One adult male cat was used in two experiments. In each experiment, three isotope protocols were tested in triplicate using the same cat. During carbon oxidation study days, the cat was offered thirteen small meals to achieve and maintain a physiological fed state. In experiment 1, the isotope protocols tested (A, B and C) had a similar priming dose of NaH13CO3 (0⋅176 mg/kg; offered in meal 6), but different priming [4⋅8 mg/kg (A) or 9⋅4 mg/kg (B and C); provided in meal 6] and constant [1⋅04 mg/kg (A and B) or 2⋅4 mg/kg (C); offered in meals 6-13] doses of L-[1-13C]-Phe. In experiment 2, the isotope protocols tested (D, E and F) had similar priming (4⋅8 mg/kg; provided in meal 5) and constant (1⋅04 mg/kg; provided in meals 5-13) doses of L-[1-13C]-Phe, but increasing priming doses of NaH13CO3 (D: 0⋅264, E: 0⋅352, F: 0⋅44 mg/kg; provided in meal 4). Breath samples were collected using respiration chambers (25-min intervals) and CO2 trapping to determine 13CO2:12CO2. Isotopic steady state was defined as the enrichment of 13CO2, above background samples, remaining constant in at least the last three samples. Treatment F resulted in the earliest achievement of 13CO2 steady state in the cat's breath. This feeding and isotope protocol can be used in future studies aiming to study amino acid metabolism in cats.
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Affiliation(s)
- Julia Guazzelli Pezzali
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, Canada
- Department of Animal Science, Iowa State University, Ames, IA, United States
| | - Jocelyn G. Lambie
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, Canada
| | | | - Anna K. Shoveller
- Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, ON, Canada
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Singh P, Banton S, Raheb S, Templeman JR, Saunders-Blades J, Kostiuk D, Kelly J, Marinangeli CP, Verbrugghe A, Verton-Shaw S, Shoveller AK. The Pulse of It: Dietary Inclusion of Up to 45% Whole Pulse Ingredients with Chicken Meal and Pea Starch in a Complete and Balanced Diet Does Not Affect Cardiac Function, Fasted Sulfur Amino Acid Status, or Other Gross Measures of Health in Adult Dogs. J Nutr 2023; 153:1461-1475. [PMID: 36972833 DOI: 10.1016/j.tjnut.2023.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/19/2023] [Accepted: 03/22/2023] [Indexed: 03/28/2023] Open
Abstract
BACKGROUND Pulses are an attractive alternative protein source for all mammals; however, recent reports suggest that these ingredients may be related to developing dilated cardiomyopathy in dogs. OBJECTIVES The primary objective of this study was to quantify the effects of dietary pulse intake by adult dogs on cardiac function using echocardiographic measurements and cardiac biomarkers N-terminal pro-B-type natriuretic peptide and cardiac troponin I (cTnI). Second, to investigate the effects of pulse consumption on plasma sulfur amino acid (SAA) concentrations as pulses are generally low in SAA and may limit taurine synthesis. Last, to assess the general safety and efficacy of feeding pulse-containing diets on canine body composition and hematological and biochemical indices. METHODS Twenty-eight privately-owned domestic Siberian Huskies (13 females; 4 intact, and 15 males; 6 intact) with a mean age of 5.3 ± 2.8 y (± SD) were randomly assigned to 1 of 4 dietary treatments (n = 7/treatment), with equal micronutrient supplementation and increasing whole pulse ingredient inclusion (0%, 15%, 30%, and 45%) with pea starch used to balance protein and energy. RESULTS After 20 wks of feeding, there were no differences (P > 0.05) in echocardiographic parameters, N-terminal pro-B-type natriuretic peptide, and cTnI concentrations among treatments or across time within treatment (P > 0.05), indicating no differences in cardiac function among treatments. Concentrations of cTnI remained below the safe upper limit of 0.2 ng/mL for all dogs. Plasma SAA status, body composition, and hematological and biochemical indices were similar among treatments and over time (P > 0.05). CONCLUSIONS The results from this study suggest that increasing the inclusion of pulses up to 45% with the removal of grains and equal micronutrient supplementation does not impact cardiac function concurrent with dilated cardiomyopathy, body composition, or SAA status and is safe for healthy adult dogs to consume when fed for 20 wks.
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Affiliation(s)
- Pawanpreet Singh
- Department of Animal Biosciences, Ontario Agricultural College, Guelph, Ontario, Canada
| | - Sydney Banton
- Department of Animal Biosciences, Ontario Agricultural College, Guelph, Ontario, Canada
| | - Shari Raheb
- Department of Clinical Studies, Ontario Veterinary College, Guelph, Ontario, Canada
| | - James R Templeman
- Department of Animal Biosciences, Ontario Agricultural College, Guelph, Ontario, Canada
| | | | | | | | | | - Adronie Verbrugghe
- Department of Clinical Studies, Ontario Veterinary College, Guelph, Ontario, Canada
| | - Shoshana Verton-Shaw
- Department of Clinical Studies, Ontario Veterinary College, Guelph, Ontario, Canada
| | - Anna K Shoveller
- Department of Animal Biosciences, Ontario Agricultural College, Guelph, Ontario, Canada.
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Pezzali JG, Rafii M, Courtney-Martin G, Cant JP, Shoveller AK. Applying the indicator amino acid oxidation technique in the domestic cat: results of a pilot study and development of a non-steady state prediction model. J Anim Sci 2023; 101:skac390. [PMID: 36434784 PMCID: PMC10007698 DOI: 10.1093/jas/skac390] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
The aim of this study was to evaluate whether the indicator amino acid oxidation (IAAO) method could be applied in the domestic cat. Six adult male cats were used in a replicated 3 × 3 Latin square design. Three semi-synthetic diets were developed: a methionine (Met) and total sulfur AA (TSAA) deficient diet (T-BASAL; 0.24% Met+Cys - DM basis) and two Met and TSAA-sufficient diets in which either dl-Met (T-DLM) or 2-hydroxy-4-(methylthio)-butanoic acid (T-MHA) were supplemented, respectively, on an equimolar basis to meet the TSAA requirement (0.34%). After a 2-d diet adaptation, IAAO studies were performed. Cats were offered 13 small meals. The sixth meal contained a priming dose (4.8 mg/kg-BW) of l-[1-13C]-Phe and the remaining meals a constant dose (1.04 mg/kg-BW). Breath samples were collected every 25 min to measure 13CO2 enrichment. The following morning, fasted blood samples were collected. Cats returned to the T-BASAL top dressed with a dl-Met solution for 4 d prior to being fed a new dietary treatment. Isotopic steady state was evaluated through visual inspection. Data were analyzed using PROC GLIMMIX procedure in SAS 9.4. While 13CO2 enrichment was successfully captured in breath samples, cats failed to reach 13CO2 steady state. Thus, a non-steady state isotope model was developed and coded in ACSLX (V3.1.4.2) individually for each cat on each study day to predict 13CO2 enrichment, and then, calculate oxidation of l-[1-13C]-Phe (F13CO2). A higher predicted F13CO2 was observed for cats fed T-BASAL compared to the others (P < 0.05), while no differences were observed between T-DLM and T-MHA (P > 0.05). Cats fed T-DLM tended to have higher plasma Met concentrations compared to those fed T-BASAL with cats fed T-MHA intermediate (P = 0.0867). Plasma homocysteine concentrations were higher in cats fed T-BASAL compared to the others (P < 0.05), while threonine concentrations tended to be higher in cats fed T-BASAL compared to those fed T-MHA (P = 0.0750). In conclusion, short-term provision of a semi-synthetic diet deficient in Met may elicit a metabolic response aiming to conserve Met. The successful quantification of 13CO2 enrichment in breath and the higher predicted F13CO2 in cats fed a Met deficient diet suggest that the IAAO technique may be used in cats. Adaptations in the isotope protocol should be made to achieve 13CO2 steady state in breath and avoid mathematical modeling to predict F13CO2.
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Affiliation(s)
- Julia Guazzelli Pezzali
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| | - Mahroukh Rafii
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - John P Cant
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| | - Anna K Shoveller
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
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Pezzali JG, Bullerwell A, Dancy K, DeVries TJ, Shoveller AK. The development of a semisynthetic diet deficient in methionine for adult cats for controlled feline nutrition studies: effects on acceptability, preference, and behavior responses. J Anim Sci 2023; 101:skac392. [PMID: 36440575 PMCID: PMC9838793 DOI: 10.1093/jas/skac392] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Chemically defined diets are commonly used in amino acid (AA) requirement studies to allow for tight control of AA delivery. However, those diets are not representative of commercial diets in the market and are unpalatable. Methionine (Met) is usually the first limiting AA in cat diets, but little is known about its requirement for adult cats. Thus, the objectives of this study were: 1) to develop a semisynthetic diet limiting in Met and evaluate its effect on acceptance and feeding behavior in cats; and 2) to evaluate the effect of different sources and inclusions of Met on preference in cats fed the semisynthetic diet. A semisynthetic diet deficient in Met and total sulfur AA (TSAA) was developed. Healthy adult male cats (n = 9) were fed (0800 and 1600 h) the semisynthetic diet top dressed with DL-Met solution (T-DLM), to meet 120% of the TSAA requirement, for 8 d. Feed intake was measured and a 30-min video recording was taken at the 0800 h feeding to evaluate feeding behavior of the cats. Following the acceptability trial, two bowl tests were performed where first choice was recorded and intake ratio was calculated as consumed food (A/A + B). Three combinations were tested: semisynthetic diet deficient in Met (T-BASAL) vs. T-DLM; T-BASAL vs. diet sufficient in Met provided 2-hydroxy-4-(methylthio)-butanoic acid (T-MHA); and T-DLM vs. T-MHA. Average feed intake remained high throughout the acceptability period (94.5% intake of total offered), but some cats decreased intake, resulting in a decrease in BW (≤2.5% of initial BW) over time (P < 0.05). Behaviors were similar among days (P > 0.05) with the exception of grooming the chest and body (P < 0.05). No preferences were observed towards a specific treatment (Met source and level) during the two-bowl tests (P > 0.05) and agreed with the cats expressing similar feeding behaviors during the preference tests (P > 0.05). In conclusion, a semisynthetic diet deficient in Met was successfully developed and can be used in studies to evaluate the effects of low protein and AA supplemented diets. Cats seem to show no preference for Met source and/or inclusion level in a semisynthetic diet application, which is of benefit for future studies aiming to determine the Met requirement in this species.
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Affiliation(s)
| | - Asha Bullerwell
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| | - Kaitlyn Dancy
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| | - Trevor J DeVries
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| | - Anna K Shoveller
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
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Mansilla WD, Templeman JR, Fortener L, Shoveller AK. Minimum dietary methionine requirements in Miniature Dachshund, Beagle, and Labrador Retriever adult dogs using the indicator amino acid oxidation technique. J Anim Sci 2021; 98:5917805. [PMID: 33011778 PMCID: PMC7751151 DOI: 10.1093/jas/skaa324] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/29/2020] [Indexed: 11/24/2022] Open
Abstract
The objective of this study was to determine the minimum requirement (MR) for methionine (Met), when cyst(e)ine (Cys) is provided in excess, in adult dogs of three different breed sizes using the indicator amino acid (AA) oxidation (IAAO) technique. In total, 12 adult dogs were used: 1 neutered and 3 spayed Miniature Dachshunds (4.8 ± 0.4 kg body weight [BW], mean ± SD), 4 spayed Beagles (9.5 ± 0.7 kg BW, mean ± SD), and 4 neutered Labrador Retrievers (31.8 ± 1.7 kg BW, mean ± SD). A deficient Met basal diet with excess Cys was formulated. Dogs were fed the basal diet randomly supplemented with different Met-Alanine (Ala) solutions to achieve final Met concentrations in experimental diets of 0.21%, 0.26%, 0.31%, 0.36%, 0.41%, 0.46%, and 0.66% (as-fed basis). After 2 d of adaptation to the experimental diets, dogs underwent individual IAAO studies. During the IAAO study day, the total feed was divided into 13 equal meals; at the sixth meal, dogs were fed a bolus of l-[1-13C]-phenylalanine (Phe), and thereafter, l-[1-13C]-Phe was supplied with every meal. The total production of 13CO2 during isotopic steady state was determined by the enrichment of 13CO2 in breath samples, and the total production of CO2 measured using indirect calorimetry. The mean MR for Met and the upper 95% confidence limit (CL) were determined using a two-phase linear mixed-effects regression model. For Miniature Dachshunds, the MR for Met was between the first two dietary Met concentrations and is, therefore, between 35.7 and 44.1 mg.kg BW−1·d−1 (0.21% to 0.26%, as-fed basis; no requirement could be determined on a metabolic BW basis). For Beagles and Labrador Retrievers, the MR for Met was 57.5 and 50.4 mg.kg BW−1·d−1, 107.7 and 121.8 mg/kg BW^0.75, or 0.338 and 0.360%, respectively (as-fed basis). The upper 95% CL of Met requirements was 77.9 and 72.4 mg.kg BW−1·d−1, 147.8 and 159.6 mg/kg BW^0.75,or 0.458 and 0.517% for Beagles, and Labradors, respectively (as-fed basis). When pooling data from Beagles and Labrador Retrievers, the MR and upper 95% CL were 56.0 and 75.8 mg.kg BW−1·d−1 or 118.4 and 150.5 mg/kg BW^0.75 or 0.360% and 0.482% (as-fed basis). In conclusion, the MR and the upper 95% CL for Met are different for Dachshunds when compared with Beagles and Labrador Retrievers. Using this low-protein diet, the estimated upper 95% CL Met requirement for Beagles and Labrador is higher than those recommended in the National Research Council (NRC), but NRC is similar to the estimated upper 95% CL for Dachshunds.
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Affiliation(s)
| | - James R Templeman
- Department of Animal Biosciences, University of Guelph, Guelph, Canada
| | | | - Anna K Shoveller
- Department of Animal Biosciences, University of Guelph, Guelph, Canada.,Procter & Gamble Co., Pet Care, Mason, OH
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