SIST EN 16967:2017
(Main)Animal feeding stuffs: Methods of sampling and analysis - Predictive equations for metabolizable energy in feed materials and compound feed (pet food) for cats and dogs including dietetic food
Animal feeding stuffs: Methods of sampling and analysis - Predictive equations for metabolizable energy in feed materials and compound feed (pet food) for cats and dogs including dietetic food
This draft European Standard defines predictive equations for the determination of ME in:
- products of vegetable or animal origin, in their natural state, fresh or preserved, such as meat, offal, milk products, cooked starch sources; highly digestible special products such as milk substitutes or diets for enteral nutrition;
- complete or complementary products derived from the industrial processing for cats and dogs.
Futtermittel - Probenahme- und Untersuchungsverfahren - Schätzgleichungen für umsetzbare Energie in Futtermittel-Ausgangserzeugnissen und Mischfuttermitteln (Heimtierfutter) für Katzen und Hunde, einschließlich Diätfuttermittel
Dieser Europäische Norm-Entwurf definiert Vorhersagegleichungen zur Bestimmung der verstoffwechselbaren Energie (ME) (en: metabolizable energy) von:
- Produkten pflanzlichen oder tierischen Ursprungs in deren natürlichem Zustand, frisch oder konserviert, wie beispielsweise Fleisch, Innereien, Michprodukte, gekochte Stärkequellen; leicht-verdauliche Spezialprodukte wie beispielsweise Milchersatzprodukte oder Nahrung für enterale Ernährung;
- vollständigen oder ergänzenden Produkten, die aus der industriellen Verarbeitung für Katzen und Hunde stammen.
Aliments pour animaux : Méthodes d’échantillonnage et d’analyse - Équations prédictives de l’énergie métabolisable dans les matières premières pour aliments et les aliments composés (aliments pour animaux de compagnie) pour chats et chiens, y compris les aliments diététiques
Le présent projet de Norme européenne définit les équations prédictives pour la détermination de l’EM contenue dans :
- les produits d’origine végétale ou animale, dans leur état naturel, qu’ils soient frais ou conservés, tels que la viande, les abats, les produits laitiers, les sources d’amidon cuit, ou des produits spéciaux hautement digestibles tels que des laits de remplacement ou des régimes alimentaires pour la nutrition entérale ;
- les produits complets ou les compléments alimentaires pour les chats et les chiens, issus de la transformation industrielle.
Krma: metode vzorčenja in analize - Napovedne enačbe za presnovno energijo v krmilih in krmnih mešanicah (hrane za hišne živali) za mačke in pse, vključno z dietično hrano
Ta osnutek evropskega standarda določa napovedne enačbe za določanje presnovne energije v:
– izdelkih rastlinskega in živalskega izvora v naravni obliki, svežih ali konzerviranih, kot so meso, drobovina, mlečni izdelki, kuhani viri škroba; lahko prebavljivi posebni izdelki, kot so mlečni nadomestki ali diete za enteralno prehrano;
– popolnih ali dopolnilnih izdelkih, pridobljenih z industrijsko obdelavo za mačke in pse.
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Futtermittel - Probenahme- und Untersuchungsverfahren - Schätzgleichungen für umsetzbare Energie in Futtermittel-Ausgangserzeugnissen und Mischfuttermitteln (Heimtierfutter) für Katzen und Hunde, einschließlich DiätfuttermittelAliments pour animaux : Méthodes d’échantillonnage et d’analyse - Équations prédictives de l’énergie métabolisable dans les matières premières pour aliments et les aliments composés (aliments pour animaux de compagnie) pour chats et chiens, y compris les aliments diététiquesAnimal feeding stuffs: Methods of sampling and analysis - Predictive equations for metabolizable energy in feed materials and compound feed (pet food) for cats and dogs including dietetic food65.120KrmilaAnimal feeding stuffsICS:Ta slovenski standard je istoveten z:EN 16967:2017SIST EN 16967:2017en,fr,de01-september-2017SIST EN 16967:2017SLOVENSKI
STANDARD
SIST EN 16967:2017
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16967
July
t r s y ICS
x wä s t r English Version
Animal feeding stuffsã Methods of sampling and analysis æ Predictive equations for metabolizable energy in feed including dietetic food Aliments pour animaux ã Méthodes d 5échantillonnage et d 5analyse æ Équations prédictives de l 5énergie métabolisable dans les matières premières pour les aliments diététiques
Futtermittel æ Probenahmeæ und Untersuchungsverfahren æ Schätzgleichungen für umsetzbare Energie in FuttermittelæAusgangserzeugnissen und Mischfuttermitteln Diätfuttermittel This European Standard was approved by CEN on
s v May
t r s yä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels
9
t r s y CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s x { x yã t r s y ESIST EN 16967:2017
EN 16967:2017 (E) 2 Contents European foreword . 3 Introduction . 4 1 Scope . 5 2 Normative references . 5 3 Terms and definitions . 5 4 Principle . 6 4.1 Determination of GE . 6 4.2 Determination of DE . 6 4.3 Determination of ME . 6 4.4 Mathematical prediction of ME in food for cats and dogs . 7 4.5 Conversion factors . 7 4.6 Nitrogen-free extract (NFE) . 7 5 Reagents and materials . 7 6 Apparatus . 7 7 Sampling . 8 8 Sample preparation . 8 9 Measurements . 8 9.1 Moisture. 8 9.2 Protein (crude) . 8 9.3 Fat (crude) . 8 9.4 Ash (crude) . 8 9.5 Fibre (crude) . 8 10 Determination of energy by calculation . 8 10.1 Complete or complementary compound feed for dogs and cats . 8 10.2 Examples . 10 10.3 Other products . 11 11 Accuracy . 11 12 Tolerances . 12 13 Test report . 12 Annex A (informative)
General background information . 13 A.1 Pet Food from Industrial Processing (PFIP) . 13 A.2 Determination of ME in PFIP . 13 A.3 Development of the factors . 13 Annex B (informative)
Metabolizable energy in pet food – a comparison between the accuracy of predictive formulae versus experimental determination . 15 B.1 Background . 15 B.2 Materials and methods . 15 B.3 Results . 16 B.4 Discussion . 30 Bibliography . 31 SIST EN 16967:2017
EN 16967:2017 (E) 3 European foreword This document (EN 16967:2017) has been prepared by Technical Committee CEN/TC 327 “Animal feeding stuffs - Methods of sampling and analysis”, the secretariat of which is held by NEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2018, and conflicting national standards shall be withdrawn at the latest by January 2018. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 16967:2017
EN 16967:2017 (E) 4 Introduction Balanced nutrition enabling adequate intake of energy, protein, minerals and vitamins is essential for cats and dogs to allow health and longevity. In order to realize the recommended intake of energy and nutrients, products need to be formulated accordingly. In other words: all essential nutrients need to be provided in the amount of diet which is needed to fulfil the daily energy requirements. The approach to provide nutrient recommendations expressed as units per MJ recognizes the close relationship between energy and nutrient intake. Hence the accurate determination of energy content in pet food is crucial for formulating appropriate diets for cats and dogs as well as the corresponding instructions for proper use. Feeding trials are the most accurate way to measure the energy density of a pet food. Since animal studies are labour and cost intensive, several predictive formulae for calculating metabolizable energy (ME) content in dog and cat foods have been developed during the years. The use of predictive formulae is a well-established method within control authorities in Member States and within the pet food industry. However, there is currently no uniformity as to their use. Considering the labelling declarations required for certain pet food products listed in Annex I to Directive 2008/38/EC it is clear that there is a need for a harmonization at EU level by means of a European Standard laying down the predictive formulae to be used. The predictive formulae in this standard will constitute simple tools to be used by control authorities and manufacturers to calculate ME by using values of dietary components determined by validated official methods (Commission regulation (EC) No 152/2009). This represents a good and robust compromise between accuracy and practicability to overcome the difficulties of feeding trials, which would be otherwise required to obtain the most accurate value of ME. SIST EN 16967:2017
EN 16967:2017 (E) 5 1 Scope This European Standard specifies predictive formulae for the determination of metabolizable energy (ME) in — products of vegetable or animal origin, in their natural state, fresh or preserved, such as meat, offal, milk products, cooked starch sources; highly digestible special products such as milk substitutes or diets for enteral nutrition; — complete or complementary products derived from the industrial processing for cats and dogs. 2 Normative references Not applicable. 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 crude fibre CF substances which are insoluble and combustible under the operating conditions specified in this standard 3.2 digestible energy DE gross energy minus energy loss in faeces Note 1 to entry: DE provides an estimate of the energy the animal is able to use. Note 2 to entry: DE does not take into account energy losses via urine (and combustible gases). 3.3 dry matter DM measurement of mass when completely dried 3.4 gross energy GE total chemical energy arising from complete combustion of a food in a bomb calorimeter Note 1 to entry: The heat of combustion in feedstuffs can be predicted from the chemical analysis using standard values for the nutrients. For pet foods appropriate GE estimates for crude fat, crude protein and carbohydrates (nitrogen-free extract (NFE) plus crude fibre (CF)) are 39,3 kJ/g [1], 23,8 kJ/g [2] and 17,1 kJ/g [3]. 3.5 metabolizable energy ME energy available to an animal after correction of the DE for losses via urine and combustible gases SIST EN 16967:2017
EN 16967:2017 (E) 6 3.6 nitrogen-free extract NFE carbohydrate fraction including starch, simple sugars and soluble parts of cellulose, hemicellulose, lignin and pectin 4 Principle 4.1 Determination of GE The GE content of a food is defined as the total chemical energy arising from complete combustion of a food in a bomb calorimeter. The heat of combustion in feedstuffs can be predicted from the chemical analysis using standard values for the nutrients. For pet foods appropriate GE estimates for crude fat, crude protein and carbohydrates (NFE plus CF) are 39,3 kJ/g [1], 23,8 kJ/g [2] and 17,1 kJ/g [3]. 4.2 Determination of DE In animal experiments the difference between the GE intake with feedstuffs and the GE loss via faeces is used to determine the digestible energy of a food. For this, GE of food and faeces is determined by complete combustion in a bomb calorimeter. Alternatively, DE can be calculated by multiplication of GE with the percentage of apparent digestibility of energy divided by 100. Formulae to estimate energy digestibility as a function of fibre have been based mainly on CF analysis for practical reasons: CF is mostly used in labelling the pet food and the methodology is well established with the added benefit of being cheap and easy to perform. Consequently, there is much more data on CF and energy digestibility than on any other fibre analysis. 4.3 Determination of ME The ME of a food is determined by subtracting energy losses via urine from the DE. In species with relevant extent of fermentation activity such as ruminants, energy losses through combustible gases are subtracted from the DE as well. Fermentation losses by gas can be neglected in dogs and cats, therefore only the separate collection of faeces and urine is required in digestion trials. In order to avoid the use of metabolic cages it is common practise to collect only faeces and to correct for energy losses via urine using a fixed value for urinary GE losses per g digested protein multiplied by the amount of digestible protein in the food. Therefore, 5,2 kJ per g digestible protein is subtracted for dogs and 3,6 kJ per g digestible protein for cats applying either the apparent protein digestibility measured in a digestion trial or a mean apparent protein digestibility of 83,5 % in dogs and 86 % in cats. SIST EN 16967:2017
EN 16967:2017 (E) 7 4.4 Mathematical prediction of ME in food for cats and dogs The predictive formulae of ME are based on the results of feeding trials. Calculation of ME in accordance to these formulae employ contents of dietary components, determined by validated official methods (Commission regulation (EC) No 152/2009). The mathematical prediction ME in food for cats and dogs can be described in four steps. 1) Estimation of GE using appropriate GE estimates for crude fat, crude protein and carbohydrate (with CF); 2) Estimation of the percentage apparent energy digestibility using a linear regression formula based on CF content per dry matter (DM); 3) Calculation of DE; 4) Conversion into ME by subtracting urinary energy losses related to protein metabolism. 4.5 Conversion factors Conversion factors kcal conversion to kJ: 1 kcal = 1 000 cal = 4,184 kJ; 1 MJ = 1 000 kJ = 239 kcal. 4.6 Nitrogen-free extract (NFE) NFE comprises the carbohydrate fraction including starch, simple sugars and soluble parts of cellulose, hemicellulose, lignin and pectin. NFE is calculated according to Formula (1). mNFE = 100 - (mM + mCP + mCFA + mCA + mCFI)
(1) where mNFE
is the mass nitrogen free extract, in g/100 g; mM is the mass moisture, in g/100 g; mCP is the mass crude protein, in g/100 g; mCFA
is the mass crude fat, in g/100 g; mCA is the mass crude ash, in g/100 g; mCFI is the mass CF, in g/100 g. 5 Reagents and materials All the reagents shall be of analytical grade. All reagents used for determination of moisture, protein, fat, ash and fibre as described under Clause 9. 6 Apparatus Usual laboratory equipment and, in particular, those for determination of moisture, protein, fat, ash and fibre. SIST EN 16967:2017
EN 16967:2017 (E) 8 7 Sampling It is important that the laboratory receives a sample that is homogenous and truly representative and has not been altered or changed during transport and storage. Sampling is not part of the method specified in this European Standard. A recommended sampling method for feed is given in Commission regulation (EC) No 152/2009 Annex I. 8 Sample preparation A recommended sampling method is given in Commission regulation (EC) No 152/2009 Annex II point A or equivalent. 9 Measurements 9.1 Moisture A recommended method is given in Commission regulation (EC) No 152/2009 Annex III, method A or equivalent. 9.2 Protein (crude) A recommended method is given in Commission regulation (EC) No 152/2009 Annex III, method C or equivalent. 9.3 Fat (crude) A recommended method is given in Commission regulation (EC) No 152/2009 Annex III, method H, Procedure B, with Hydrolysis compulsory for pet food or equivalent. 9.4 Ash (crude) A recommended method is given in Commission regulation (EC) No 152/2009 Annex III, method M or equivalent. 9.5 Fibre (crude) A recommended method is given in Commission regulation (EC) No 152/2009 Annex III, method I or equivalent. 10 Determination of energy by calculation 10.1 Complete or complementary compound feed for dogs and cats The ME in complete or complementary compound feed for dogs and cats derived from the industrial processing can be predicted with the following steps and Formulae (2) to (7). 1) Calculate GE with Formula (2) for both dog and cat foods EGE = (f × MCP) + (g × MCFA) + [j × (MNFE + MCFI)] (2) where EGE
is the GE, in MJ/kg; f
is the value of 0,02385 for the GE estimate of crude protein, in MJ/g; g is the value of 0,03933 for the GE estimate of crude fat, in MJ/g; SIST EN 16967:2017
EN 16967:2017 (E) 9 j is the value of 0,01715 for the GE estimate of carbohydrate (with CF), in MJ/g; MCP
is the mass crude protein, in g/kg; MCFA
is the mass of crude fat, in g/kg; MNFE
is the mass of NFE, in g/kg; MCFI is the mass of CF, in g/kg. 2) Calculate the apparent digestibility of gross energy with Formula (3) for dog food and Formula (4) for cat food. EDIG, d = k – (n × MCFD) (3) EDIG, c = p – (q × MCFD)
(4) where EDIG,d
is the energy digestibility in dog food, in % ; EDIG,c is the energy digestibility in cat food, in %; k is the value of 91,2 for the EDIG,d estimate; MCFD
is the mass CF in DM, in g/100 g; n
is the value of 1,43 for the impact estimate of CF on EDIG,d; p is the value of 87,9 for the EDIG,c estimate; q is the value of 0,88 for the impact estimate of CF on EDIG,c. 3) Calculate the digestible energy with Formula (5) EDE = (EGE × DGE) / 100
(5) where EDE
is the DE, in MJ/kg; EGE
is the GE, in MJ/kg; DGE is the digestibility of GE, in %. 4) Convert into metabolizable energy with Formula (6) for dog food and Formula (7) for cat food. EME,d = EDE – (r × MCP) (6) EME,c = EDE – (v × MCP) (7) where EME,d is the ME in dog food, in MJ/kg; EME,c is the ME in cat food, in MJ/kg; EDE
is the DE, in MJ/kg; MCP
is the mass crude protein, in g/kg; r
is the value of 0,00434 for the ME estimate of crude protein in dog food, in MJ/g; SIST EN 16967:2017
EN 16967:2017 (E) 10 v is the value of 0,00322 for the ME estimate of crude protein in cat food, in MJ/g. 10.2 Examples 10.2.1 Dog food Composition of the pet food (g/kg): MM = 800 MCP = 70 MCFA = 40 MCA = 30 MCFI = 10 MNFE = 50 Calculation of ME in dog food: 1) Formula (2): EGE = (0,02385 × 70) + (0,03933 × 40) + [0,01715 × (50 + 10)] = 4,27 2) Formula (3): EDIG,d = 91,2 - (0,143 × 50) = 84,05 3) Formula (5): EDE = 4,27 × 84,05/100 = 3,59 4) Formula (6): EME, d = 3,59 – (0,00434 × 70) = 3,28 10.2.2 Cat food Composition of the pet food (g/kg): MM = 800 MCP = 70 MCFA = 40 MCA = 30 MCFI = 10 MNFE = 50 Calculation of ME in cat food: 1) Formula (2): EGE = (0,02385 × 70) + (0,03933 × 40) + (0,01715 × (50 + 10)) = 4,27 2) Formula (4): EDIG,c = 87,9 - (0,088 × 50) = 83,5 SIST EN 16967:2017
EN 16967:2017 (E) 11 3) Formula (5): EDE = 4,27 × 83,5/100 = 3,57 4) Formula (7): EME, c = 3,57 – (0,003 22 × 70) = 3,34 10.3 Other products The ME in products of vegetable or animal origin, in their natural state, fresh or preserved, such as meat, offal, milk products, cooked starch sources; highly digestible special products such as milk substitutes or diets for enteral nutrition can be predicted with Formula (8) for dog food and Formula (9) for cat food. EME d = (a × MCP) + (b × MCFA) + (c × MNFE)
(8) EME,c = (a × MCP) + (e × MCFA) + (c × MNFE) (9) where a is the value of 0,016 74 for the ME estimate of crude protein, in MJ/g; b is the value of 0,037 67 for the ME estimate of crude fat in dog food; in MJ/g; c is the value of 0,016 74 for the ME estimate of carbohydrate, in MJ/g; EME,d is the ME in dog food, in MJ/kg; EME,c
is the ME in cat food, in MJ/kg; e is the value of 0,035 57 for the ME estimate of crude fat in cat food, in MJ/g; MCP
is the mass crude protein, in g/kg; MCFA
is the mass of crude fat, in g/kg; MNFE
is the mass of NFE, in g/kg. 11 Accuracy Recent reviews ([4], [5], [6]) comparing the accuracy between the modified Atwater method and the formulae cited by the National Research Council (NRC) [15] versus measured ME have shown the following: — The formulae cited by NRC [15] provide a more accurate estimate of ME compared to the modified Atwater method in dry pet foods. — The modified Atwater method and the NRC [15] formulae provide an equally moderate accuracy of ME estimation for wet foods for both dogs and cats. — Based on the above-mentioned findings it appears that the predictive formulae as laid down in this standard represent a robust compromise between accuracy and practicability. In summary no substantial advantage is achieved by further splitting formulae to be used for dry and wet pet foods or cat and dog pet foods respectively. NOTE In dog foods with CF content above 80 g/kg DM and a high percentage of fermentable non-starch polysaccharides in the CF fraction the predictive formula can underestimate the energy density. Further details on the accuracy evaluation are provided in Annex A. SIST EN 16967:2017
EN 16967:2017 (E) 12 12 Tolerances For the official controls, a tolerance of 15 % shall be applied between the result of the inspection obtained from the formulae given in Clause 10 and the declared energy value, provided that the tolerances for discrepancies between the other labelled compositional values and the values analysed in the official controls in compliance with Commission regulation (EC) No 882/2004 are respected in line with Annex IV of Commission regulation (EC) No 767/2009. NOTE This tolerance of 15 % complements the tolerances given in Commission regulation (EC) No 767 (Section IV, A, 2.e). 13 Test report The test report shall specify: — information necessary for complete identification of the sample; — the sampling procedure if known; — the method used, with reference to this European Standard; — the calculation result(s) obtained; — operating details not specified in this European Standard, or regarded as optional, together with details of any incidents which may have influenced the calculation result(s). SIST EN 16967:2017
EN 16967:2017 (E) 13 Annex A (informative)
General background information A.1 Pet Food from Industrial Processing (PFIP) There are several different types, or formats, of pet food from industrial processing including wet (can, pouch, tray), dry (known as biscuits or kibbles) and complimentary treats. The method of production and the ingredients used varies according to format. Wet foods are made by mixing recipe ingredients together and cooking them within the can, tray or pouch. Many of the ingredients used in the manufacture of pet food are falling into the category meat and animal derivatives (MAD). In wet pet foods MAD usually arrive at the factory in a fresh or frozen state. They may be chopped and added to the recipe mix directly or finely minced, mixed with dry ingredients such as cereals, formed into ribbons and diced into chunks of various sizes and shapes. Other ingredients are included such as oils and fats, vitamins, minerals, cereals, vegetables. Once the recipe ingredients are mixed they enter the can, pouch or tray. Gravy or jelly is then added. This usually constitutes a mix of water, thickening agents and flavours. The can, pouch or tray is then sealed and enters a sterilization process. Dry pet foods are made by mixing dry and wet ingredients together. Ingredients are ground and sieved where required and brought together in a mixer. Water is added to make dough. The dough enters a preconditioner to prepare the dough for cooking. The dough then enters an extruder which steam cooks the dough. At the end of the extruder the dough exits under pressure through a die plate which cuts the string of dough into the required size and shape. After extrusion and cutting the kibbles are air-dried in an oven to remove moisture and then cooled. Reducing the moisture content is an important step in maintaining freshness and preventing food spoilage. In dry pet foods, animal derivatives are commonly used in a meal form (where meat and animal derivatives are cooked, dried and the fat is removed creating a dry meal). MAD may also be used in fresh or frozen form. Many of the other ingredients such as cereals, grains, vegetables used in dry pet foods come in dry form and are milled or ground prior to mixing. Complimentary pet food products for cats and dogs come in a variety of forms. Manufacturing technologies include extrusion, oven baking or injection moulding. A.2 Determination of ME in PFIP The Association of American Feed Control Officials (AAFCO 2015) has published accepted protocols [25] for the determination of ME of dog and cat foods in feeding trials. The factors used in predictive formulae are primarily based on fixed energy values, digestibility coefficients and a correction for predicted energy losses for nitrogen from protein metabolism via urine. However, there is no universal predictive formula that fits any given food, hence before using any formula its validity for the food in question shall be considered. A.3 Development of the factors Information on the development of the factors is provided in [7]: The first predictive equation was obtained by Rubner in 1901 in dogs and later modified by Atwater (1902). The resulting Atwater factors of 4 for protein, 9 for fat, and 4 kcal/g for carbohydrate (nitrogen-SIST EN 16967:2017
EN 16967:2017 (E) 14 free extract; NFE) still work amazingly well for ingredients in home-made diets for dogs: meat, offal (except bones and bone meal), poultry, fish, highly purified starch products, milk products, and even chocolate. In these foods, NFE consists mostly of sugar or starch. Atwater factors are also useful for products that must have a high digestibility, such as milk substitutes and liquids for enteral nutrition. Given the GE values of 4,1 kcal/g carbohydrate, 9,4 kcal/g fat, and 5,7 kcal/g protein and renal energy losses of 1,25 kcal/g digestible protein in dogs and 0.90 kcal/g digestible protein in cats, Atwater factors include a digestibility of 98 % for carbohydrate, 96 % for fat and 90 % for protein. Consequently, there are discrepancies when the equation is applied to foods with a higher content of non-starch polysaccharides such as legumes, salad, fruit, or high-fibre cereal products. For dogs, Atwater factors are still recommended for use for table food if no other data are available, as well as for milk substitutes and liquids for enteral nutrition. Atwater factors do not work as well for cats because the digestibility of fat is usually somewhat lower in cats th
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SLOVENSKI STANDARD
oSIST prEN 16967:2016
01-april-2016
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Animal feeding stuffs: Methods of sampling and analysis - Predictive equations for
metabolizable energy in complete and complementary pet food for cats and dogs
(including dietic food)
Futtermittel - Probenahme- und Untersuchungsverfahren - Vorhersagegleichungen für
verstoffwechselbare Energie in vollständigem oder ergänzendem Tierfutter für Katzen
und Hunde (einschließlich diätetisches Futter)
Aliments pour animaux - Méthodes d'échantillonnage et d'analyse - Équations
prédictives de l’énergie métabolisable dans les aliments complets et les compléments
alimentaires pour chats et chiens (y compris les aliments diététiques)
Ta slovenski standard je istoveten z: prEN 16967
ICS:
65.120 Krmila Animal feeding stuffs
oSIST prEN 16967:2016 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 16967:2016
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oSIST prEN 16967:2016
DRAFT
EUROPEAN STANDARD
prEN 16967
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2016
ICS 65.120
English Version
Animal feeding stuffs: Methods of sampling and analysis -
Predictive equations for metabolizable energy in complete
and complementary pet food for cats and dogs (including
dietic food)
Bestimmung des Energiewerts in Heimtierfutter
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 327.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16967:2016 E
worldwide for CEN national Members.
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Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
4.1 General . 5
4.2 Gross energy (GE) . 6
4.3 Digestible energy (DE) . 6
4.4 Metabolizable energy (ME) . 6
4.5 Mathematical prediction of metabolizable energy (ME) in food for cats and dogs. 6
4.6 Conversion factors . 6
4.7 Nitrogen-free extract (NFE) . 6
5 Reagents and materials . 7
6 Apparatus . 7
7 Sampling . 7
8 Sample preparation . 7
9 Measurements . 7
10 Determination of energy by calculation . 8
10.1 Natural state . 8
10.2 Industrial state . 8
10.3 Examples . 9
10.3.1 Dog food . 9
10.3.2 Cat food . 9
11 Accuracy . 9
12 Tolerances . 10
13 Test report . 10
Annex A (informative) General background information . 11
A.1 General . 11
A.2 Development of the factors . 11
Annex B (informative) Report for the Scientific Advisory Board of the FEDIAF . 13
B.1 General . 13
B.2 Background . 13
B.3 Materials and methods . 13
B.4 Results . 14
B.5 Discussion . 22
Bibliography . 24
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European foreword
This document (prEN 16967:2016) has been prepared by Technical Committee CEN/TC 327 “Animal
feeding stuffs - Methods of sampling and analysis”, the secretariat of which is held by NEN.
This document is currently submitted to the CEN Enquiry.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
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Introduction
Balanced nutrition enabling adequate intake of energy, protein, minerals and vitamins is essential for
cats and dogs to allow health and longevity. In order to realize the recommended intake of energy and
nutrients, products need to be formulated accordingly. In other words: all essential nutrients need to be
provided in the amount of diet which is needed to fulfil the daily energy requirements. The approach to
provide nutrient recommendations expressed as units per MJ recognizes the close relationship between
energy and nutrient intake. Hence the accurate determination of energy content in pet food is crucial for
formulating appropriate diets for cats and dogs as well as the corresponding instructions for proper
use.
Feeding trials are the most accurate way to measure the energy density of a pet food. Since animal
studies are labour and cost intensive, several predictive equations for calculating metabolizable energy
(ME) content in dog and cat foods have been developed during the years. The use of predictive
equations is a well-established method within control authorities in Member States and within the pet
food industry. However, there is currently no uniformity as to their use. Considering the labelling
declarations required for certain pet food products listed in Annex I to Directive 2008/38/EC it is clear
that there is a need for a harmonization at EU level by means of a European Standard laying down the
predictive equations to be used.
The predictive equations in this standard will constitute simple tools to be used by control authorities
and manufacturers to calculate ME by using values of dietary components determined by validated
official methods (Regulation (EC) No 152/2009). This represents a good and robust compromise
between accuracy and practicability to overcome the difficulties of feeding trials, which would be
otherwise required to obtain the most accurate value of ME.
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1 Scope
This draft European Standard defines predictive equations for the determination of ME in:
— products of vegetable or animal origin, in their natural state, fresh or preserved, such as meat, offal,
milk products, cooked starch sources; highly digestible special products such as milk substitutes or
diets for enteral nutrition;
— complete or complementary products derived from the industrial processing for cats and dogs.
2 Normative references
Not applicable.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
digestible energy
DE
gross energy of feedstuff minus the gross energy lost in faeces
Note 1 to entry DE provides an estimate of the energy the animal is able to use.
Note 2 to entry DE does not take into account energy losses via urine (and combustible gases).
3.2
gross energy
GE
total chemical energy arising from complete combustion of a food in a bomb calorimeter
Note 1 to entry The heat of combustion in feedstuffs can be predicted from the chemical analysis using
standard values for the nutrients. For pet foods appropriate GE estimates for crude fat, crude protein and
carbohydrates (NFE plus crude fibre) are 39,3 kJ/g, 23,8 kJ/g and 17,1 kJ/g, respectively [1–3].
3.3
metabolizable energy
ME
energy available to an animal after correction of the DE for losses via urine and combustible gases
4 Principle
4.1 General
In animal experiments the difference between the GE intake with feedstuffs and the GE loss via faeces is
used to determine the digestible energy of a food. For this, GE of food and faeces is determined by
complete combustion in a bomb calorimeter. Alternatively, DE can be calculated by multiplication of GE
with the percentage of apparent digestibility of energy divided by 100. Equations to estimate energy
digestibility as a function of fibre have been based mainly on crude fibre (CF) analysis for practical
reasons: crude fibre is mostly used in labelling the pet food and the methodology is well established
with the added benefit of being cheap and easy to perform. Consequently, there is much more data on
crude fibre and energy digestibility than on any other fibre analysis.
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4.2 Gross energy (GE)
The gross energy (GE) content of a food is defined as the total chemical energy arising from complete
combustion of a food in a bomb calorimeter. The heat of combustion in feedstuffs can be predicted from
the chemical analysis using standard values for the nutrients. For pet foods appropriate GE estimates
for crude fat, crude protein and carbohydrates (NFE plus crude fibre) are 39,3 kJ/g, 23,8 kJ/g and
17,1 kJ/g, respectively [1]-[3].
4.3 Digestible energy (DE)
In animal experiments the difference between the GE intake with feedstuffs and the GE loss via faeces is
used to determine the digestible energy of a food. For this, GE of food and faeces is determined by
complete combustion in a bomb calorimeter. Alternatively, DE can be calculated by multiplication of GE
with the percentage of apparent digestibility of energy divided by 100. Equations to estimate energy
digestibility as a function of fibre have been based mainly on crude fibre (CF) analysis for practical
reasons: crude fibre is mostly used in labelling the pet food and the methodology is well established
with the added benefit of being cheap and easy to perform. Consequently, there is much more data on
crude fibre and energy digestibility than on any other fibre analysis.
4.4 Metabolizable energy (ME)
The ME of a food is determined by subtracting energy losses via urine from the DE. In species with
relevant extent of fermentation activity such as ruminants, energy losses through combustible gases are
subtracted from the DE as well. Fermentation losses by gas can be neglected in dogs and cats, therefore
only the separate collection of faeces and urine is required in digestion trials. In order to avoid the use
of metabolic cages it is common practise to collect only faeces and to correct for energy losses via urine
using a fixed value for urinary GE losses per g digested protein multiplied by the amount of digestible
protein in the food. Therefore, 5,2 kJ/g digestible protein is subtracted for dogs and 3,6 kJ/g digestible
protein for cats applying either the apparent protein digestibility measured in a digestion trial or a
mean apparent protein digestibility of 83,5 % in dogs and 86 % in cats.
4.5 Mathematical prediction of metabolizable energy (ME) in food for cats and dogs
The predictive equations of ME are based on the results of feeding trials. Calculation of ME in
accordance to these equations employ contents of dietary components, determined by validated official
methods (Regulation (EC) No 152/2009). The mathematical prediction of metabolizable energy (ME) in
food for cats and dogs can be described in four steps:
1) estimation of gross energy (GE) using appropriate GE estimates for crude fat, crude protein and
carbohydrate (with crude fibre);
2) estimation of the percentage apparent energy digestibility using a linear regression equation based
on crude fibre content per dry matter;
3) calculation of digestible energy (DE) (GE × aD GE/100);
4) conversion into ME by subtracting urinary energy losses related to protein metabolism.
4.6 Conversion factors
Conversion factors Kcal conversion to kJ: 1 kcal = 1 000 cal = 4,184 kJ; 1 MJ = 1 000 kJ = 239 kcal.
4.7 Nitrogen-free extract (NFE)
NFE comprises the carbohydrate fraction including starch, simple sugars and soluble parts of cellulose,
hemicellulose, lignin and pectin. NFE is calculated according to Formula (1):
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NFE = 100 - (% moisture + % crude protein + % crude fat + % crude ash + % crude fibre) (1)
where
NFE = nitrogen free extract, in %.
5 Reagents and materials
All the reagents shall be of analytical grade.
All reagents used for determination of moisture, protein, fat, ash and fibre as described under Clause 9,
“Measurements”.
6 Apparatus
Usual laboratory equipment and, in particular, those for determining moisture, protein, fat, ash and
fibre.
7 Sampling
It is important that the laboratory receives a sample that is homogenous and truly representative and
has not been altered or changed during transport and storage.
Sampling is not part of the method specified in this European Standard. A recommended sampling
method for feed is given in Regulation (EC) No 152/2009 Annex I or equivalent.
8 Sample preparation
A recommended sampling method is given in Regulation (EC) No 152/2009 Annex II point A or
equivalent.
9 Measurements
9.1 Moisture.
NOTE Regulation (EC) No 152/2009 Annex III, method A is applicable.
9.2 Protein (crude).
NOTE Regulation (EC) No 152/2009 Annex III, method C is applicable.
9.3 Fat (crude).
NOTE Regulation (EC) No 152/2009 Annex III, method H, Procedure B, with Hydrolysis compulsory for pet
food (7.3) is applicable.
9.4 Ash (crude).
NOTE Regulation (EC) No 152/2009 Annex III, method M is applicable.
9.5 Fibre (crude).
NOTE Regulation (EC) No 152/2009 Annex III, method I is applicable.
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10 Determination of energy by calculation
10.1 Natural state
The metabolizable energy (ME) in products of vegetable or animal origin, in their natural state, fresh or
preserved, such as meat, offal, milk products, cooked starch sources; highly digestible special products
such as milk substitutes or diets for enteral nutrition can be predicted with Formula (2a) for dog food
and Formula (2b) for cat food.
ME(dogs) = (0,016 74 × g/kg crude protein) + (0,037 67 × g/kg crude fat) + (0,016 74 × g/kg NFE)
(2a)
ME(cats) = (0,016 74 × g/kg crude protein) + (0,035 57 × g/kg crude fat) + (0,016 74 × g/kg NFE)
(2b)
where
ME = Metabolizable energy, in MJ/kg.
10.2 Industrial state
The metabolizable energy (ME) in complete or complementary products for dogs and cats derived from
the industrial processing van be predicted with the following steps and Formulae (3) to (6).
1) Calculate GE with Formula (3) for both dog and cat foods.
GE = (0,02385 × g/kg crude protein) + (0,03933 × g/kg crude fat) +
[0,01715 × (g/kg NFE + g/kg crude fibre)] (3)
where
GE = Gross energy, in MJ/kg.
2) Calculate the apparent digestibility of gross energy with Formula (4a) for dog food and
Formula (4b) for cat food.
% energy digestibility (dogs) = 91,2 – (1,43 × % crude fibre in dry matter) (4a)
% energy digestibility (cats) = 87,9 – (0,88 × % crude fibre in dry matter) (4b)
3) Calculate the digestible energy with Formula (5).
DE = (GE × digestibility of GE (%)) / 100 (5)
where
DE = digestible energy, in MJ/kg;
GE = gross energy, in MJ/kg.
4) Convert into metabolizable energy with Formula (6a) for dog food and equaition (6b) for cat food.
ME(dogs) = DE – (0,004 34 × g/kg crude protein) (6a)
ME(cats) = DE – (0,003 22 × g/kg crude protein) (6b)
where
ME = metabolizable energy, in MJ/kg;
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DE = gross energy, in MJ/kg.
10.3 Examples
10.3.1 Dog food
Composition of the pet food:
— 80 % moisture
— 7 % crude protein
— 4 % crude fat
— 3 % crude ash
— 1 % crude fibre
— 5 % NFE
Calculation of the ME:
Step 1, Formula (3): GE = (0,023 85 × 70) + (0,039 33 × 40) + [0,017 15 × (50 + 10)] = 4,27 MJ/kg
Step 2, Formula (4a): Percentage energy digestibility = 91,2 - (0,143 × 50) = 84,05 %
Step 3, Formula (5): DE = 4,27 × 84,05/100 = 3,59 MJ/kg
Step 4, Formula (6a): ME = 3,59 – (0,004 34 × 70) = 3,28 MJ/kg
10.3.2 Cat food
Composition of the pet food:
— 80 % moisture
— 7 % crude protein
— 4 % crude fat
— 3 % crude ash
— 1 % crude fibre
— 5 % NFE
Calculation of the ME:
Step 1, Formula (3): GE = (0,023 85 × 70) + (0,039 33 × 40) + (0,01715 × (50 + 10)) = 4,27 MJ/kg
Step 2, Formula (4b): Percentage energy digestibility = 87,9 - (0,088 × 50) = 83,5 %
Step 3, Formula (5): DE (MJ/kg) = 4,27 × 83,5/100 = 3,57 MJ/kg
Step 4, Formula (6b): ME (MJ/kg) = 3,57 – (0,003 22 × 70) = 3,34 MJ/kg
11 Accuracy
Recent reviews [4-6] comparing the accuracy between the modified Atwater method and the equations
cited by NRC (2006; [7]) versus measured ME have shown the following:
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— The equations cited by NRC (2006; [7]) provide a more accurate estimate of ME compared to the
modified Atwater method in dry pet foods;
— The modified Atwater method and the NRC (2006; [7]) equations provide an equally moderate
accuracy of ME estimation for wet foods for both dogs and cats.
Based on the above-mentioned findings it appears that the predictive equations as laid down in this
standard represent a robust compromise between accuracy and practicability. In summary no
substantial advantage is achieved by further splitting equations to be used for dry and wet pet foods or
cat and dog pet foods respectively.
NOTE In dog foods with crude fibre content above 80 g/kg dry matter and a high percentage of fermentable
NSP in the crude fibre fraction the predictive equation can underestimate the energy density [7].
Further details on the accuracy evaluation are provided in Annex A.
12 Tolerances
If the official inspection reveals a discrepancy between the result of the inspection and the declared
energy value, a tolerance of 15 % shall be applied.
NOTE This is provided that the tolerances for discrepancies between the other labelled compositional values
and the values analyzed in the official controls in compliance with Regulation (EC) No 882/2004 are respected in
line with Annex IV of Regulation (EC) No 767/2009.
13 Test report
The test report shall specify:
a) information necessary for complete identification of the sample;
b) the sampling procedure if known;
c) the method used, with reference to this European Standard;
d) the calculation result(s) obtained;
e) operating details not specified in this European Standard, or regarded as optional, together with
details of any incidents which may have influenced the calculation result(s).
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Annex A
(informative)
General background information
A.1 General
The Association of American Feed Control Officials [8] has published accepted protocols for the
determination of ME of dog and cat foods in feeding trials. The factors used in predictive equations are
primarily based on fixed energy values, digestibility coefficients and a correction for predicted energy
losses for N from protein metabolism via urine. However, there is no universal predictive equation that
fits any given food, hence before using any equation its validity for the food in question shall be
considered.
A.2 Development of the factors
Information on the development of the factors is provided in National Research Council, Nutrient
Requirements of Dogs and Cats ([7], pages 29-30):
The first predictive equation was obtained by Rubner in 1901 in dogs and later modified by Atwater
(1902). The resulting Atwater factors of 4 for protein, 9 for fat, and 4 kcal/g for carbohydrate (nitrogen-
free extract; NFE) still work amazingly well for ingredients in home-made diets for dogs: meat, offal
(except bones and bone meal), poultry, fish, highly purified starch products, milk products, and even
chocolate. In these foods, NFE consists mostly of sugar or starch. Atwater factors are also useful for
products that must have a high digestibility, such as milk substitutes and liquids for enteral nutrition.
Given the GE values of 4,1 kcal/g carbohydrate, 9,4 kcal/g fat, and 5,7 kcal/g protein and renal energy
losses of 1,25 kcal/g digestible protein in dogs and 0,90 kcal/g digestible protein in cats, Atwater factors
include a digestibility of 98 % for carbohydrate, 96 % for fat and 90 % for protein. Consequently, there are
discrepancies when the equation is applied to foods with a higher content of non-starch polysaccharides
such as legumes, salad, fruit, or high-fibre cereal products. For dogs, Atwater factors are still recommended
for use for table food if no other data are available, as well as for milk substitutes and liquids for enteral
nutrition. Atwater factors do not work as well for cats because the digestibility of fat is usually somewhat
lower in cats than in dogs (Figge, 1989). Provided starchy food is cooked, the factors for carbohydrate (4
kcal/g) and protein (4 kcal/g) are appropriate for the cat, whereas 8.5 kcal/g is recommended to estimate
ME for fats in table food.
The original factors in the equation described by Atwater were modified for dogs and cats by Kendall et
al. [9], [10]. The modified Atwater factors for dogs and cats (14,65 kJ/g protein, 35,56 kJ/g fat, and
14,65 kJ/g carbohydrate) provide reasonable estimates of ME for commercial pet foods with
digestibility in the range of 75 % to 85 %. Other equations to estimate energy content of pet foods have
also been developed by other researchers, in order to account for the impact of relative fibre content or
presumed digestibility and to avoid underestimation of energy content of highly digestible foods and
overestimation of those of less digestible foods. It should be noted that predictive equations rely on the
determination of dietary components by validated official methods as laid down in Regulation (EC)
No 152/2009 or other validated standard methods [8], [11]. For example, predictive equations have
been designed to take into account the fibre content of the food (crude fibre or total dietary fibre (TDF),
or the amino acid and non-amino acid compounds in the crude protein fraction to predict ME better.
The critical component of equations for ME estimation is the calculation of energy digestibility, which
can be predicted by linear regression of the fibre content on a dry matter basis [12]. Equations to
estimate energy digestibility as a function of fibre have been based mainly on crude fibre (CF) analysis
for practical reasons.
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a) The methodology is well established with an analytical Level of Quantification (LoQ) of 1 to 2 g/kg
wet weight finished product (laboratory specific) as well as the added benefit of being cheap and
easy to perform.
b) The use of crude fibre covers a wide range of prepared dog and cat foods.
c) Crude fibre is used in pet food labelling.
Consequently, there is much more data on crude fibre and energy digestibility than on any other fibre
analysis [13-16], which showed a satisfactory agreement between predicted and experimentally
determined digestibility, with outliers mainly in pet foods with a crude fibre content of more than
80 g/kg dry matter [17].
It is, however, possible to accurately predict energy digestibility as a function of other fibre
measurements, including total fibre and total dietary fibre (TDF), as long as they determine the major
percentage of cellulose [15], [16]. An equation based on TDF, as specified by the American Organization
of Analytical Chemists method [8], has been developed [18] and validated for use with dog and cat foods
[19].
Total dietary fibre analyses [20] comprises most non-starch polysaccharides and li
...
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