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

Feed to Ideal Body Condition

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