是时候重新考虑NRC和AAFCO关于犬类氨基酸需求的指导原则了吗？.pdf

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1、Sarah M.Dickerson,Claire L.Timlin,Fiona B.Mccracken,Craig N.CoonIs It Time to Reconsider NRC and AAFCO Guidelines for Amino Acid Requirements in Dogs?Dogs have an amino acid requirement,not necessarily a protein requirement Limited by the least available nutrient Methionine Lysine High protein foods

2、 not doing any good if the amino acid requirements are not metCurrent State of RequirementsAAFCO is main source referenced for nutrient requirementsMuch of AAFCO data derived from NRC requirementsAAFCO values typically greater than the NRC values to try and account for differences in bioavailability

3、Current State of RequirementsAmino AcidAAFCO minimum(g/1000 kcal ME)NRC Minimum Requirement(g/1000 kcal ME)NRC Recommended Allowance(g/1000 kcal/ME)Methionine0.880.650.83Lysine2.250.700.88TSAA(Methionine+Cysteine)1.751.301.63AAFCO&NRC guidelines provide nutritional recommendations for only two categ

4、ories of dogs:Adult Maintenance Growth and ReproductionSenior dogs represent increasing percentage of pet populationVarieties of breeds and sizes available,while most research done on a select fewOlder,less efficient research methods used in previous studiesAge-specific Canine NutritionRecent studie

5、s from our lab and others have reported the amino acid requirements of dogs at different life stages and in various size breeds.Is it time to update AAFCO&NRC guidelines?Age-specific Canine NutritionBased on concept of limiting amino acidMeasuring oxidation via breath samples for indirect measuremen

6、t of tissue incorporationPros:Applicable to all breeds,sizes,and species;Cons:costs,requires indirect calorimetry equipment and isotope,and multiple sampling daysIndicator Amino Acid OxidationIndicator Amino Acid Oxidation TechniqueFeed control diet 2 days(adaptation),test diet 1 day.Six total test

7、diets(3 excess;3 deficient)Breath sample collected every 30 min via respiration mask and calorimetryIndicator Amino Acid Oxidation TechniqueFEEDINGISOTOPECO2 PRODUCTIONENRICHMENTAll dogs receive priming dose of 13C L-Phenylalanine after 2hr of feeding,then smaller bolus dose every 30min for 4hrs13C

8、enrichment of breath CO2 samples determined by isotope ratio mass spectrometry(IRMS)IAAOAdapted from Elango et.al,2012 Decreasing IAAO reflects increasing utilization of limiting AA for protein synthesisOxidation Level(measured by 13-C)Amino Acid Intake=dietIAAOAdapted from Elango et.al,2012 No furt

9、her change in IAAO=requirement for limiting amino acid has been met=dietOxidation Level(measured by 13-C)Amino Acid IntakeIAAOAdapted from Elango et.al,2012 No further change in IAAO=requirement for limiting amino acid has been metEARRDA+2 SD=dietOxidation Level(measured by 13-C)Amino Acid IntakeRes

10、ults from Recent Studies AAFCOFEDIAFNRCMini Dachs.BeagleLabrador RetrieverMin.ReqRec.Allow.Min.ReqRec.Allow.Min.Req.Rec.Allow.Lysg/100 g DM 0.630.460.280.35N/A0.460.550.440.53Adapted from Sutherland et al.,2020*4000 kcal/kg MEResults from Recent StudiesAAFCOFEDIAFNRCMini Dachs.BeagleLabrador Retriev

11、erMin.ReqRec.Allow.Min.ReqRec.Allow.Min.Req.Rec.Allow.Lysg/100 g DM 0.630.460.280.35N/A0.460.550.440.53Adapted from Sutherland et al.,2020*4000 kcal/kg MEResults from Recent StudiesAAFCOFEDIAFNRCMini Dachs.BeagleLabrador RetrieverMin.ReqRec.Allow.Min.ReqRec.Allow.Min.Req.Rec.Allow.Lysg/100 g DM 0.63

12、0.460.280.35N/A0.460.550.440.53Adapted from Sutherland et al.,2020*4000 kcal/kg MEFRK PopulationResults from Recent StudiesNRC Minimum Methionine Recommendations(g/1000 kcal ME)Puppies10-14wksPuppies 14 wksYoung AdultsSeniors0.70.530.65NAFRK Methionine Minimum Requirements(+2 SD)(g/1000 kcal ME)Pupp

13、ies10-14wksPuppies 14 wksYoung AdultsSeniors0.84(+0.05)0.78(+0.16)0.68(+0.19)0.62(+0.17)Results from Recent StudiesNRC Minimum TSAA Recommendations (g/1000 kcal ME)Puppies10-14wksPuppies 14 wksYoung AdultsSeniors1.41.051.3NAFRK TSAA Minimum Requirements(+2 SD)(g/1000 kcal ME)Puppies10-14wksPuppies 1

14、4 wksYoung AdultsSeniors1.55(+0.07)1.53(+0.21)1.4(+0.30)1.27(+0.23)Results from Recent StudiesResults from Recent StudiesAmino acid metabolic availability from different protein sources adds an extra layer of complexity to formulating dog foodsRequirement may be met from an analytical perspective,bu

15、t is it fully utilized?Must be digestible can be taken up in the intestines during digestionMust also be bioavailable after digestion,it can be utilized by the tissuesMetabolic Availability of Amino AcidsMuch of the available data is from digestibility studies,but there are some issues:Cant perform

16、cannulated dog studiesCecetomized rooster assaysTotal tract digestibility involves colonic fermentation/microbial digestion and can skew dataThese dont investigate beyond digestibilityIAAO can provide better insight into AA bioavailabilityMetabolic Availability of Amino AcidsMetabolic Availability o

17、f Amino AcidsHuman studies finding highly variable AA bioavailability in foodstuffsFoodAmino AcidPopulationMetabolic Availability(%)Soy protein isolateMethionineYoung adult males71.8CaseinMethionineYoung adult males87.4White riceLysineYoung adult males97LentilsLysineYoung adult males80ChickpeasMethi

18、onineYoung adult males63Adapted from Paoletti et al.,2024 reviewPotentially some unexpected findings in pet food ingredients:Decreased availability of chicken meal compared to peasMetabolic Availability of Amino AcidsCrosbie et al.,2024Metabolic Availability of Amino AcidsIngredientSlope%Bioavailabl

19、eSoy protein isolate-0.06582.3%Crystalline Leu-0.079100%(assumed)Data is very limited for amino acids using the IAAO technique in companion animalsThe little data presented would suggest AAFCO is meeting at least some requirements for adult animals(2 7 years old)More research on bioavailability of i

20、ngredients and food types is neededHowever,requirements may also be overestimated,especially with our senior animalsConclusionsOptimizing diets for senior dogs to improve longevity and quality of life Lots of marketing for it,not a lot of published data available yetSustainability Consideration More

21、 precise formulations reduce waste and over-supplementation Need to be careful in how this is approach and how much we can extrapolate across breeds,sizes,and agesAlternative proteinsResearch funding opportunities neededImplications for Pet Food IndustryAcknowledgementsFour Rivers Kennel Team:Mary FuquaSarah DickersonPatrick SkaggsBrooke WilkinsonJason FowlerDanielle FisherTanya WebbBecky Bedford GehmannSpecial Thanks To:Contact Us/Learn More Contact Us/Learn More