08 Dog and Cat Nutrition

Dog and Cat Nutrition : Dog and Cat Nutrition


Species Differences : Species Differences Dog – Binge eaters (bloat), taste sensitive to acids, amino acids and sweets Cat – Meal eaters, taste sensitive to acids, amino acids, but not sweets


What exactly is a carnivore (nutritionally)? : What exactly is a carnivore (nutritionally)? Obligate or true carnivores Have protein requirements 2-5 times greater than omnivores or herbivores Adult cat has 5x greater protein requirement than adult dog


Digestive Anatomy of Dogs : Digestive Anatomy of Dogs


Digestive Anatomy of Cats : Digestive Anatomy of Cats


Nutritional Idiosyncrasies : Nutritional Idiosyncrasies High protein requirement Specific requirement for 2 amino acids: Arginine Taurine Arachidonic acid Preformed vitamin A Preformed vitamin D Inability to convert tryptophan to niacin


Feline Nutrient Requirements (AAFCO) : Feline Nutrient Requirements (AAFCO) Nutrient Maintenance Growth Protein, % 26 30 Fat, % 9 9 Linoleic Acid, % 0.5 0.5 Arachidonic Acid, % 0.02 0.02 Vitamin A, IU/kg 5,000 9,000 Vitamin D, IU/kg 500 750 Niacin, mg/kg 60 60 Taurine (extruded), % 0.10 0.10 Taurine (canned), % 0.20 0.20


Canine Nutrient Requirements (AAFCO & NRC) : Canine Nutrient Requirements (AAFCO & NRC) Nutrient Maintenance Fox, NRC Protein, % 18 22 Fat, % 5 - Linoleic Acid, % 1 1 Arachidonic Acid, % - - Vitamin A, IU/kg 5,000 - Vitamin D, IU/kg 500 - Niacin, mg/kg 11.4 - Taurine (extruded), % - - Taurine (canned), % - -


NRC Publications : NRC Publications For livestock species, serve as the “gold standard” for nutritional requirements Swine Beef cattle Dairy cattle Sheep Only recently has this been the case for dogs and cats


2005 Dog and Cat NRC : 2005 Dog and Cat NRC Both species combined in 1 publication Current version: ~450 pages 1985 dog and 1986 cat: ~80 pages each Margin of safety included Classically and conditionally essential nutrients included


Energy Requirements of Dogs and Cats : Energy Requirements of Dogs and Cats


Carbohydrates (CHO) : Carbohydrates (CHO) CHO includes simple sugars (glucose) and complex sugars (starches – are chains of simple sugars) No true requirement for CHO as such, but animals do have a requirement for glucose or adequate glucose precursors (gluconeogenic amino acids, glycerol)


Carbohydrates (CHO) : Carbohydrates (CHO) Sugars and cooked starches are economical and easily digested sources of energy Uncooked starches are less digestible Dogs respond to the taste of sugars, cats do not Digestion of sugars (ex - sucrose, lactose) depends on intestinal enzyme activity specific for individual sugar compounds Lack of or low enzyme activity frequently results in diarrhea – hind gut fermentation


Unique Challenges to Feeding Dogs : Unique Challenges to Feeding Dogs Drastic differences in energy requirements Age Reproductive status Body condition Activity level Breed Temperament Health status Environmental conditions


Energy Requirement - Dogs : Energy Requirement - Dogs Great genetic diversity Size differences Chihuahua: less than 1 kg Irish Wolfhound: over 100 kg Maintenance energy requirements may range from 110 to ~4,000 kcal/d


Energy Requirements - Cats : Energy Requirements - Cats Breed differences are much smaller Weight ranges 3 – 10 kg Growth curves consistent Life spans up to 32 years – if they avoid being road-kill


Energy Requirements Adjusted for Body Size : Energy Requirements Adjusted for Body Size


Strength/Power Activities : Strength/Power Activities RACING GREYHOUNDS Greyhounds – 57% muscle mass – (other species approximately 40%) 50% fast-twitch muscle fibers (other species 0-50%) Designed for sprints – short distances, very fast pace (36 mph) Energy requirement increases 15-30% when training and running OPTIMAL DIET – A high percent of carbohydrates and proteins and lower fat content


Diet Requirements : Diet Requirements High digestibility Palatable  Low bulk Maximum energy density Minimum gut weight Counteract stress Optimal recovery Maintain immune responses and disease prevention  


Intermediate Activities : Intermediate Activities HUNTING/SPORTING DOGS Activity level between 2-4 minutes at a time Use of the glycolytic and oxidative pathways for energy OPTIMAL DIET – a well balanced mixture of carbohydrate, proteins, and fat


Diet Requirements : Diet Requirements High digestibility Palatable/readily accepted during training Easy to prepare Stable at normal temperatures Moderate carbohydrates, moderate to high fat, moderate protein


Endurance Activities : Endurance Activities SLED DOGS Sled dogs – more slow twitch muscle fibers – built for endurance Utilize oxidative metabolism for energy Cold weather increases energy requirement 70-80% even with heavy hair coat


Sled Dogs : Sled Dogs Heavy work and competition lead to physiological and psychological stress Iditarod performance: ~10 miles/hr 10-14 hours/day 1158 miles in less than 10 days 100-150 miles/day Burn up to 10,000 kcal/day


Energy Needs : Energy Needs Energy requirements = 5-10x maintenance Fatty acids are principal energy source Aerobic energy system Primarily oxidative metabolism Also good for combating cold OPTIMAL DIET – high fat, moderate protein, and low amounts of carbohydrates


Factors Affecting Performance : Factors Affecting Performance GENETICS TRAINING NUTRITION


Challenges : Challenges Assume 60 lb dog – high quality dry food Average dog - 1400 kcal/day (3.4 cups) Greyhound – 1800 kcal/day (4.2 cups) Sled dog maintenance – 2700 kcal/day (6.5 cups) Sled dog racing – 12,200 kcal/day (29 cups)


Nutritional Diseases : Nutritional Diseases Obesity Largest problem in the pet food industry Lack of exercise and unrestricted food intake


Fats and Fatty Acids for Dogs and Cats : Fats and Fatty Acids for Dogs and Cats


Fats – essential fatty acids : Fats – essential fatty acids Essential fatty acids – those fatty acids that the body cannot make enough of to meet the body’s needs Linoleic (18:2, n-6), α-linolenic (18:3, n-3), and arachidonic (20:4, n-6) Linoleic and α-linolenic are precursors for longer chain fatty acids


Long Chain Polyusaturated Fatty Acids : Long Chain Polyusaturated Fatty Acids Mammals can’t synthesize linoleic acid and a-linolenic acid These fatty acids are essential Monounsaturated fatty acids can be converted to other physiologically important PUFA’s through the enzyme, 6 desaturase Cats have limited activity of this enzyme


EFA Elongation : EFA Elongation Linoleic Acid (18:2 n6) 18:3 n6 20:3 n6 20:4 n6 Arachidonic Acid Linolenic acid (18:3 n3) 18:4 n3 20:4 n3 20:5 n3 Eicosapentanoic Acid D 6 Desaturase elongase D 5 Desaturase Bibus, D.M. 1997


Essential Fatty Acid Deficiency Signs : Essential Fatty Acid Deficiency Signs Poor growth Poor coat/hair quality Slow wound healing Increased susceptibility to infection


Most Mammals : Most Mammals Linoleic acid prevents most deficiency signs Signs of a-linolenic acid deficiency less severe Arachidonic acid synthesized from linoleic acid


Arachidonic Acid Requirement of Cats : Arachidonic Acid Requirement of Cats Cats fed diets with linoleic acid, but without arachidonic acid: Listless Dandruff Increased infections Infertility Very low plasma concentrations of amino acids


Lack of 6 Desaturase Activity in Cats : Lack of 6 Desaturase Activity in Cats When given labeled linoleic acid, no labeled arachidonic acid or other long chain fatty acids with 3 or 4 double bonds. Cats Lions


Practical Implications : Practical Implications Linoleic acid – plentiful in plant oils Arachidonic acid – NOT found in plants, common in animal products (meat, milk, etc)


Deficiency Signs Can Be Noted When: : Deficiency Signs Can Be Noted When: Cats fed cereal based dog diets If not supplemented with meat or other source of arachidonic acid Large felids (zoo settings) Ex, cheetahs in South African zoo (Davidson et al., 1986) Cheetahs fed meat based diet, showed deficiency signs, when supplemented with fish oil, symptoms went away


Fatty Acids and Early Neonatal Development : Fatty Acids and Early Neonatal Development Significant amount of brain growth occurs in the early neonatal period in dogs, cats, rats Require large amounts of long chain PUFA for neural development Provided by milk fatty acid composition


Docosahexanoic Acid (DHA), Arachidonic Acid, and Development : Docosahexanoic Acid (DHA), Arachidonic Acid, and Development Insufficient DHA associated with visual impairment (high in outer rod segment cells of retina) DHA shown to improve learning ability in rats and humans Arachidonic acid required for vascular development and regulation of blood flow


Long Chain PUFA Intake : Long Chain PUFA Intake Nursing neonatal animals have higher circulating DHA than formula fed Best if formula fed animals supplemented with DHA and arachidonic acid


Fats : Fats As the number of double bonds in the fats increase, so does the potential for lipid oxidation and rancidity Rancidity decreases palatability, leads to destruction of fat soluble vitamins, flavor changes, potential for formation of toxic compounds (aldehydes, ketones, acids) Antioxidants are necessary in pet foods!


The Role of Fatty Acids in the Treatment of Canine Atopic Dermatitis : The Role of Fatty Acids in the Treatment of Canine Atopic Dermatitis


Canine Atopic Dermatitis : Canine Atopic Dermatitis An allergic skin disease caused by immunological hypersensitivity to common substances in the environment Can be treated with essential fatty acids Nesbitt, 1984


Fatty Acid Biochemistry : Fatty Acid Biochemistry n-3 and n-6 fatty acids compete for the same enzymatic pathways Elongation pathway Eicosanoid production Products from n-3 fatty acids are much less inflammatory than n-6 fatty acids Exception is -linolenic acid, an n-6 fatty acid, products are less inflammatory Campbell, 1990


Eicosanoid Production : Eicosanoid Production Arachidonic acid (20:4 n6) Eicosapentanoic acid (20:5 n3) lipoxygenase lipoxygenase cyclooxygenase Prostaglandins PGE2 PGI2 TXA2 Prostaglandins PGE3 PGI3 TXA3 Leukotrienes LTB4 LTC4 LTE4 Leukotrienes LTB5 LTC5 LTE5 Proinflammatory Less inflammatory


Dietary EFA and Atopy : Dietary EFA and Atopy The manipulation of dietary n-6 and n-3 has the ability to affect inflammatory response Dietary fatty acids are incorporated into cell membrane phospholipids Release from mast cells causes conversion to eicosanoids and inflammation Optimizing quantities of dietary n-6 and n-3 fatty acids may prevent or treat the symptoms with atopic disease inflammation


Dietary Supplementation : Dietary Supplementation


What Are Supplements? : What Are Supplements? Capsules that contain specific EFA -linolenic acid, eicosapentanoic acid, g-linolenic acid Common brands: EFA-vet, Dermacaps


Supplementation Problems : Supplementation Problems Does not take into account dietary fatty acids Difficult to achieve an effective fatty acid profile Switching diets alters profile Could result in unbalanced ratios Excessive n-3 can affect blood clotting Owner compliance Several pills must be given to dog each day Supplements are expensive


Direct Diet Inclusion : Direct Diet Inclusion


What is Direct Inclusion? : What is Direct Inclusion? Formulating diets to contain specific amounts or ratios of n-6: n-3 fatty acids Commonly seen in commercially available diets


Altering Diet Formulation : Altering Diet Formulation A n-6: n-3 diet of 5.3:1 was efficacious reducing pruritis Some dogs require higher amounts of n-3 fatty acids to control pruritis 64% of dogs previously supplemented had a good to excellent response in this study n-3 concentration was 5-7 X higher with direct incorporation than with supplementation Scott et al., 1997


Current Recommendations : Current Recommendations Increased intake of n-3 fatty acids. Four PUFA – linoleic acid, alpha-linoleic acid, n-6 long chain PUFAs (arachidonic acid), n-3 long chain PUFAs (eicosapentanoic acid, docosahexanoic acid (DHA)) – should be considered separately Use of ratios unhelpful in determining status


Protein Requirements of Dogs and Cats : Protein Requirements of Dogs and Cats


Protein Requirement : Protein Requirement NRC, 2005 *g/1000 kcal ME


Protein Requirement : Protein Requirement AAFCO, 2004 * % Dry Matter Basis


Protein Requirement of Cats : Protein Requirement of Cats Kittens require approximately 1.5 times more protein than adolescent omnivores Cats require 2 to 3 times more protein than adult omnivores


Why Are the Protein Requirements of Cats So Different? : Why Are the Protein Requirements of Cats So Different?


Evolutionary Considerations : Evolutionary Considerations Omnivorous Carnivorous


Carnivorous Animals : Carnivorous Animals Have survived using a single type of food Meat does not provide complete nutrition Deficiencies of essential nutrients Evolved adaptive metabolic pathways to handle nutrient imbalance Adaptations are key to success of carnivores


Cats Have Increased Protein Required For Maintenance : Cats Have Increased Protein Required For Maintenance % of protein intake


Why the High Requirement? : Why the High Requirement? Possible reasons: High requirement for one or more EAA Higher than normal requirement for N


High Amino Acid Requirement? : High Amino Acid Requirement?


Essential Amino Acids : Essential Amino Acids Adding individual EAA requirement equals approximately 14% protein Estimated using purified amino acids Recommendation for cat is 26% About 10% more than the EAA requirement


High Nitrogen Requirement? : High Nitrogen Requirement?


Partitioning Protein Utilization : Partitioning Protein Utilization Kirk et al., 2000 * % of protein intake


Enzyme Adaptation : Enzyme Adaptation Most mammals have the ability to adapt enzyme activity to protein intake Conservation of AA when consuming low-protein diets Catabolism of AA when consuming high-protein diets Rat enzyme activity can increase 2.75 to 13.0 fold


Enzyme Activity : Enzyme Activity High activity of alanine and aspartic transaminases Constant AA catabolism Urea cycle enzymes have high activity Particularly high arginase activity Cat cannot conserve N from the body pool Cats excrete 360 mg urinary nitrogen/kg body weight -0.75 per day Excretion of dogs is 110 mg/kg BW -0.75/d No adaptation to changes in protein intake Catabolize a substantial amount of protein, particularly after a meal Catabolism regardless of meal’s protein content


Carnivorous Diet : Carnivorous Diet No selection pressure to adapt to low-protein diet Dependent on high-protein diet as a result No need for carnivore to conserve protein Cat has evolved to have increased protein metabolism: AA catabolism Irreversible rate of urea synthesis Increased protein needs for maintenance


Advantages of High Catabolism : Advantages of High Catabolism Immediate capability of cat to use AA as a source of energy Gluconeogenic enzymes are constantly active Quickly convert C-backbone of AA to energy


Arginine and Taurine Requirements : Arginine and Taurine Requirements


Arginine : Arginine Essential amino acid Can be synthesized by animals, but required for growth in rat, chick, dog NOT required for maintenance of most species Exceptions: cat, ferret, dog


Arginine Deficiency in the Cat : Arginine Deficiency in the Cat


Cats Fed Arginine-free Diet : Cats Fed Arginine-free Diet After fed a single arginine-free meal: Cats had severe hyperammonemia Lethargy Emesis Hyperglycemia Hypersalivation Inability to stand Rapid weight loss (5-10% BW in 24h) Morris and Rogers, 1978


Reasons for Arginine Reqirement In Cats : Reasons for Arginine Reqirement In Cats Extreme sensitivity to deficiency Constitutively high AA catabolism and high NH3 production Limited capacity to synthesize ornithine


Arginine Deficiency in the Dog : Arginine Deficiency in the Dog


Adult Dogs Fed Arginine-free Diets : Adult Dogs Fed Arginine-free Diets Increased blood ammonia Emesis (vomiting) by 2nd day Muscle tumors Frothing at the mouth Decreased food consumption Loss of body weight


Arginine Requirements of Adult Dogs : Arginine Requirements of Adult Dogs Adult dogs require arginine Consequences of arginine-free diet are rapid and reflect serious changes in pathway of N-excretion Not an issue when feeding diets containing natural feed ingredients Arginine requirement low (0.28%)


Taurine Requirement of the Cat : Taurine Requirement of the Cat


Taurine : Taurine Sulfur amino acid Not found in plant proteins Synthesized from methionine or cysteine


Conjugation of Bile Acids : Conjugation of Bile Acids Taurine used in bile acid conjugation Cats can only use taurine (taurocholic acid) Cats cannot conjugate bile acids with glycine (glycocholic acid)


Other Functions of Taurine : Other Functions of Taurine Retinal function Normal myocardial function Retina and myocardium contain 300-400x the taurine found in plasma Necessary for normal reproduction in queens


Taurine Deficiency : Taurine Deficiency FCRD – feline central retinal degeneration Cats fed low protein/vitamin A deficient diet had retinal and corneal lesions Vitamin A corrected corneal lesions Taurine deficiency caused retinal lesions Taurine deficiency can cause blindness within 9 months


Role of Taurine in Retinal Tissue : Role of Taurine in Retinal Tissue Taurine regulates Ca++/K+ flux in retina Without taurine, Photoreceptors are disrupted/ dysfunctional Degeneration of retina tissue Abnormal electroretinograms at 5-6 months Blindness at 9-12 months


Taurine Deficiency : Taurine Deficiency DCM – dilated cardiomyopathy Without taurine, decreased myocardial contractivity Cardiac failure Reversible with taurine re-supplementation May play role in Ca++/K+ flux in myocardial cells (improves membrane integrity)


Practical Concerns : Practical Concerns Taurine sources: Plant-based feedstuff sources do not contain taurine Animal products (meat, poultry, fish) contain 0.1 – 0.2% taurine (DM basis) Crystalline taurine


Diet Processing : Diet Processing In the mid to late 80’s, reports of several canned commercial diets leading to decreased plasma taurine and increased incidence of FCRD and DCM


Plasma Taurine, nmol/mL : Plasma Taurine, nmol/mL Hickman et al., 1990


Heat Processing : Heat Processing Increased passage of taurine to large intestine (less digestible) Increased fecal excretion Increased bacterial degradation


Taurine Requirement of Cats : Taurine Requirement of Cats Deficiency results in FCRD and DCM Low in plant sources (cats require meat) Higher concentration needed when heat processed (canned foods)


Unique Vitamin and Mineral Issues of Dogs and Cats : Unique Vitamin and Mineral Issues of Dogs and Cats


Pro-vitamin A in Plants : Pro-vitamin A in Plants b-carotene Most notable example Principle precursor found in plants b-carotene absorbed in the small intestine 15,15’-dioxygenase converts to vitamin A in the small intestinal mucosa In theory, two molecules of vitamin A are produced from 1 molecule of b-carotene


Cats and Foxes : Cats and Foxes Can’t convert b-carotene to vitamin A Lack 15,15’-dioxygenase in small intestinal mucosa Require performed vitamin A (retinol) in the diet


Companion Animal Diets : Companion Animal Diets Supplemented with retinol Deficiencies rare However, storage of pet food important Susceptible to loss during storage Storage for long times, especially at high temperatures, can decrease vitamin A


Vitamin A Toxicity (Hypervitaminosis A) : Vitamin A Toxicity (Hypervitaminosis A) Cats may be more prone to development of vitamin A toxicity than other species Beta-carotene absorption usually inefficient Regulated by small intestinal mucosa Unlikely to accumulate large amounts in body Retinol absorption not regulated in the small intestine Increase intake Increased absorption Toxic levels can accumulate


Deforming Cervical Spondylosis : Deforming Cervical Spondylosis Caused by prolonged excessive vitamin A intake Symptoms: Bony exostoses on cervical vertebrae Pain Difficult movement Lameness


Deforming Cervical Spondylosis : Deforming Cervical Spondylosis Requires vitamin A consumption at 200-800 times the requirement for 4 -24 weeks When fed commercial diets, cats will never approach this level of intake However, if fed liver/milk for extended periods, cats have been reported to develop DCS Liver and cod liver oil should not be used as frequent supplements for cats Contain high concentrations of vitamin A


Vitamin D : Vitamin D


Synthesis in the Skin : Synthesis in the Skin 7-dehydrocholesterol (7-DHC) – precursor in the skin UV light converts to previtamin D3 Then, thermally induced conversion to D3


Signs of deficiency : Signs of deficiency Initially, general reluctance to move and more time resting Progresses into posterior paralysis Quadriparesis in severe cases Decreased intake Decrease in body weight Hypocalcemia and increased PTH Morris, 1996


Why Can’t Cats Synthesize Vitamin D? : Why Can’t Cats Synthesize Vitamin D?


Skin concentrations of 7-DHC : Skin concentrations of 7-DHC Morris, 1999


Vitamin D Concentration of Cat’s Natural Diet : Vitamin D Concentration of Cat’s Natural Diet Morris, 1999


Toxicity : Toxicity Toxicity can occur if fed high vitamin D and imbalanced Ca:P ratio Not a problem with commercial diets Can be a problem if cats are fed large amounts of table scraps


Vitamin D Levels in Human Foods Fed to Cats : Vitamin D Levels in Human Foods Fed to Cats Fuller and Casparian, 2001


Vitamin E : Vitamin E Vitamin E (alpha-tocopherol) – normal functions Acts with Se to protect cell membrane damage from lipid oxidation Role in immunity Body’s need is increased as dietary PUFAs are increased


Peroxidation of Fats in Diets : Peroxidation of Fats in Diets Causes rancidity and loss of nutritional value of essential fatty acids Increased PUFA, increased risk of oxidation Increases dietary vitamin E requirement If no increase in vitamin E, can result in pansteatitis


Pansteatitis (Yellow Fat Disease) : Pansteatitis (Yellow Fat Disease) PUFA in body fat are oxidized to peroxides/hyrdoperoxides Over time, accumulation of these compounds Inflammation of adipose tissue yellow-brown discoloration of body fat


Pansteatitis (Yellow Fat Disease) : Pansteatitis (Yellow Fat Disease) Depression Anorexia Thorax/abdomen – painful to touch Reluctance to move


Treatment/Prevention : Treatment/Prevention Disease results from vitamin E deficiency due to high PUFA intake Increased vitamin E intake will correct AAFCO (cat food profiles) recommends increasing vitamin E by 10 IU/kg for each g/kg fish oil in diet


Vitamin E Deficiency : Vitamin E Deficiency Skeletal muscular dystrophy Reproductive failure Reduced immune response


Niacin : Niacin B-vitamin Conditionally essential in most animals Can be synthesized from the amino acid, tryptophan


Efficiency of Conversion : Efficiency of Conversion Varies among species Generally quite low Rats and humans – produce 1 mg niacin per 35-60 mg tryptophan Niacin requirements are low compared to tryptophan intake, so animals generally don’t develop deficiencies on low niacin diet if adequate tryptophan intake


Cats and Niacin : Cats and Niacin Cats fed niacin free diets with tryptophan died within 20 days Why?


Synthesis of Niacin : Synthesis of Niacin Little synthesis of niacin from tryptophan in the cat Tryptophan metabolites are diverted to production of picolinic acid However, niacin is usually plentiful in animal products


Copper Toxicity : Copper Toxicity High copper reduces absorption of iron and zinc Copper toxicosis (inherited disorder) is known to occur in Bedlington Terriers, West Highland Terriers, Dobermann Pinschers hepatitis and liver cirrhosis