Nutrition of Companion Animals – 2March 13, 2013
M.E. PersiaIowa State University4/16/2012
Nutrient Requirements for Dogs and Cats
• NRC for Domestic Cat (National Research Council)– National Academies
• www.nap.edu = $265.50
• AAFCO (Association of American Feed Control Officials)– www. aafco.org = $50.00
NRC Presentation of Requirements• Expressed relative to ME
– ME determines the amount of food consumed.– If energy density of the diet changes, nutrients don’t change if expressed
on an ME basis.– 4,000 Kcal per Kg.
• Accounts for variation among diets in ME
• Expressed relative to MBW– Limitation in that it’s based on calculations from assumptions
• 15 Kg dog consuming 1,000 Kcal daily = maintenance• 5.5 Kg puppy consuming 1,000 Kcal daily = growth• 22 Kg lactating female with 8 puppies consuming 5,000 Kcal daily = lactation
– Expressed as a factor of Metabolic Body Weight (MBW):• BWKg 0.75 for dogs• BWKg 0.67 for cats
Why basing on ME is more idealEnergy Density of Diet,
(Kcal of ME per Kg)
To consume 240 Kcal 4,000 (4.0 Kcal/g) 3,000
Amount feed to meet energy (g) 60 = (240 Kcal/4 Kcal/g)
80
Nutrient requirement 0.48 g/day
If nutrient density is the same 0.008 g/g food 0.48 0.64
Adjusted nutrient concentration (g) 0.008 0.006 = 0.48 / 80
To correct when you don’t have a 4,000 Kcal diet: (Nutrient requirement x Kcal of ME in diet) / 4,000 = adjusted requirement•= (0.48 g /day x 3,000 Kcal)/4000 Kcal = 0.36 g / day•Can also be done on an individual basis
Canine Nutrient Recommended Allowances - Dogs (2006, NRC)
Nutrient Amt/Kg DM Amt/1,000Amt/MBW
(4000 Kcal) Kcal (Kg0.75)
Protein (g) 100 25 3.28Fat (g) 55 13.8 1.8Vitamin A, (RE) 1,515 379 50Vitamin D (ug) 13.8 3.4 0.45Vitamin E (mg) 30 7.5 1.0Calcium (g) 4.0 1.0 0.13Phosphorus (g) 3.0 0.75 0.10
Feline Nutrient Recommended Allowances (2006, NRC)
Nutrient Amt/Kg DM Amt/1,000Amt/MBW
(4000 Kcal) Kcal (Kg0.67)
Protein (g) 200 50 4.96Fat (g) 90 22.5 2.2Vitamin A, (RE) 1,000 250 24.7Vitamin D (ug) 7 1.75 0.17Vitamin E (mg) 38 10 0.94Calcium (g) 2.9 0.72 0.071Phosphorus (g) 2.6 0.64 0.063Taurine (g) 0.40 0.10 0.010
How much to feed: energy requirements
• Based on resting energy requirement (RER) modified by a factor to account for activity and/or production and is a function of Metabolic Body Size.
• Large animals producemore heat per unit of body weight (surface area)Body surface area becamestandard for determiningenergy requirements
Problems with Body Surface Area
• Same weight – different shape• Larger issue with dogs than cats
How much to feed
• Using RER– 70 + 30 (BWKg)
– 70 (BWkg) 0.75
– 97 (BWkg) 0.67
• NRC Method – Dog: 95 – 200 x BW Kg 0.75 (common factor is 130)
• Tends to overestimate ME requirement
– Cats: 50 – 150 x BW Kg 0.67
Why that one? • Accounts a bit better for size differences in dogs• Works well for other other species – frequently used• Well accepted
Cats – Using RER• Maintenance
– 1.1 – 1.6 x RER– Weight loss = 0.8 x RER
• Gestation– 2 x RER at parturition
• Lactation– Week 1-2 = RER + 30% per kitten– Week 3 = RER + 45% per kitten– Week 4 – RER + 55% per kitten– Week 5 = RER + 65% per kitten– Week 6 = RER + 90% per kitten
• Growth– RER x 2.5
Dogs• Maintenance
– 1 – 1.8 x RER• Work
– 1.3 – 16 x RER– 16 x RER = sled dogs (Iditirod)
• Up to 11,000 Kcal day• Gestation
– Last 20 days = 2-3 x RER• Lactation
– 1 puppy = 3 x RER– 2 puppies = 3.5 x RER– 3 puppies = 4.0 x RER– 4 puppies = 5.0 x RER– 7-8 puppies = 5.5 x RER– >9 puppies = 6 x RER
• Growth– Weaning to 4 months = 3 x RER– 4 months to 80% adult weight = 2 x RER– Less for large breed – control growth
Determining ME in Diets
• Metabolism trials – collection of urine and feces: Determine GE, DE, and ME
• Modified Atwater values– Most accurate values to use when known nutrients:
• 9.4 Kcal / gram = Crude fat• 4.4 Kcal / gram = Protein• 4.2 Kcal /gram = digestible carbohydrate (CHO) = (no crude
fiber)
Determining ME in foods
• Apply digestibility coefficients use “modified” Atwater values from AAFCO.
• If not known, estimates for dogs and cats are: – 80% for protein = 3.5 Kcal / g (4.4 x 0.80) = 3.5 Kcal– 90% for fat = 8.5 Kcal / g (9.4 x 0.90) = 8.5 Kcal– 84% for CHO = 3.5 Kcal / g (4.2 x 0.84) = 3.5 Kcal
Carnivore Unique Requirements
• Obligate or True carnivores (Cats)– Protein requirements for cats are 2-5
times greater than omnivores.• Cat NRC 2006 protein = 50 g/1000 kcal• Dog NRC 2006 protein = 25 g/1000 kcal
• High protein requirement• Specific requirement for amino acids:
– Arginine (1.93 g / 1,000 Kcal ME)– Taurine (0.10 g / 1,000 Kcal ME)– Phenylalanine and tyrosine (black cats)
• Fatty Acid: Arachidonic Acid (0.015 g / 1,000 Kcal ME• Vitamin A: 833 IU / 1,000 Kcal ME• Vitamin D: 70 IU / 1,000 Kcal ME• Inability to convert tryptophan to niacin
10 mg / 1,000 Kcal ME
CATS – they are just special
Protein Metabolism – The Urea Cycle
Citrulline
ArginosuccinateArginine
Ornithine
Urea
NH 3+
Cats can not down regulate this cycle. It moves at a constant rate, always breaking down protein to supply the nitrogen to the urea cycle.
– When we eat a high protein diet:• High liver metabolic enzyme activity• High amino acid breakdown• High nitrogen disposal• High rate of gluconeogenesis
• Advantage of this metabolic adaptation: Catabolize excess amino acids and remove excess nitrogenous wastes
Black Cats
• Higher requirement for – Phenylalanine– Tyrosine
• Black color is determined by the proportion of Eumelanin (black pigment) to Pheomelanin (red-brown pigment)
• Requirement of 3.8 g/1,000 kcal
• Anderson et al. J.Nutr.132: 2037-2042, 2002
phenylalanine
Why taurine?
• What is taurine? – Free amino acid found in tissues
• Where is it found? – Heart (myocardium)
• Dilated cardiomyopathy
– Eye (retina)• Feline central retinal degeneration
– Requirement
(2006, NRC) = 0.10 g / 1, 000 Kcal
Cysteine
Taurine
Pyruvate
Arginine – Cat Requirement
• Critical for urea cycle and ammonia handling
Citrulline
ArginosuccinateArginine
Ornithine
Urea
Cats do not make arginine at a quick enough rate to keep up with nitrogen handling. Arginine deficiency will cause hyperammonemia
Arachidonic acid
• What is it? – Fatty acid– Requirement for cats = 0.015 g/1,000
kcal– Synthesized from linoleic acid
• Deficiency of arachidonic acid– Poor growth, hair loss, rough hair
coat, poor immunity, slow healing, skin lesions, fatty livers.
– Source: animal fats
Dogs and Cats Require LA: Cats specifically require Arachidonic Acid
• Conversion of the substrate linoleic acid to arachidonic acid
– Two enzymatic reactions• Desaturation and elongation
– Cats are unable to make this conversion• Lack the proper enzymes
Linoleic AcidΔ-6-desaturase
Gamma-Linoleic Acidelongase
Dihomo-Gamma-Linoleic AcidΔ-5-desaturase
Arachidonic AcidAdapted from table in “Fats You Need – Essential Fatty Acids.”
Vitamins (A, D, niacin)• Most mammals synthesize or convert compounds to active
forms of vitamins A, D, and niacin. – Tryptophan conversion to niacin.– Limited vitamin D conversion in skin.– Limited conversion of carotenoid to A.
• Very high concentrations of vitamins in liver.
Diet Decisions and Alternatives• Commercial Diets• Alternative Diets
– Whole prey– Raw
• Mixed of above
Client Reasons for Alternative Diets
• Natural ingredients• Unprocessed • Control of ingredients• Control of formulations• Provide appropriate amounts of dietary water
– Cats: Prey = 70% water; Kibble = 10% water. Impact on kidneys? • Palatability• Increased digestibility – less excrement to clean up• Less fecal odor (putrefactive compounds in feces)• Easy to manipulate• Can be specifically matched to natural history and requirements• Beneficial probiotic strains, natural enzymatic activity of meat
Whole Prey (total nutrient package): Where do nutrients come from
Hides, fur, hooves, connective tissue = provide minerals (Zn); fiber; dental health, natural glucosamine
Muscle = protein (amino acids), fat (fatty acids), energy
Organs = vitamins (A, D), protein, fat, energy, taurine, carbohydrates, fiber
Blood = protein, fat, energy, vitamins (heart), water
Bones = Minerals (calcium; dental health)
Alternative diet formulation concerns
• Bacteria• Poorly formulated
–Minerals (Ca, P, Zn, Cu, I)–Vitamins (Fat soluble vitamins,
choline)• “Diet Drift”
Issues with Raw Diets: Bacterial Contamination
• Typical home-made raw or zoo formula1,000,000 cfu
• Purchased commercial raw (HPP)10,000 cfu
• Fresh kill whole prey (elk)5,500,000 cfu
• Whole prey (rodent)2,000,000 cfu
• Considerations–Salmonella - poultry–E. coli•Problematic for
– Geriatric animals– Antibiotic treatments– Immuno-compromised animals– Humans (Salmonella recalls are greater concern for people not pets)
Whole Prey Nutrients
Item Raw diet
Rat Deer Pig
Dry matter 39.0 30.2 36.9 28.9
---------------% DM--------------
Organic Matter, % 94.8 89.3 86.2 88.1
Crude Protein, % 47.1 52.9 57.0 50.7
Fat, % 30.4 28.0 24.5 33.2
GE, kcal/g 6.5 5.9 5.6 5.8
Protein: Fat 1.5 1.9 2.3 1.5
Dierenfeld, 2002; Morris 2011 (unpublished lab data)
Domestic Cats – Diet Comparisons
Digestibility, % Grain-free Commercial Kibble
Raw beef diet
Cooked beef diet
Dry matter 78.2 86.7 83.8
Protein 81.6 93.3 92.9
Fat 91.3 95.5 95.3
Kerr et al., 2011. Journal of Animal Science
Biological Research: Comparison of Organic Matter digestibility (%) of chicken based diets in African wildcats and domestic cats
Canned Kibble Raw Diet Whole Prey
Nutrient Digestibility of extruded, raw, and cooked beef based diets in domestic cats
Item Extruded Raw Cooked
DM, % 78.2 86.7 83.8
OM, % 83.9 90.5 88.5
Protein, % 81.6 93.3 92.9
Fat, % 91.3 95.5 95.3
Energy, % 84.7 91.5 89.8
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