Cat & Dog Sensory Perception

1. Cat & Dog Sensory Perception & Pet Obesity Steven Witherly, PhD Technicalproductsinc.net

2. Steven A. Witherly, Ph.D. • B.S Dietetics UCD • M.S. Food Science UCD • PhD Nutrition • Michigan State • Carnation/Nestle/Leiner/Nutrilite • Herbalife VP of R and D • Nutraceutical Consulting • Book: “Food Pleasure Explained” • Free copy, just need Email address

3. Talk Outline • Human Perception of Food (Update) • Evolutionary Perspectives • Taste & Smell • Update of Canine and Feline Sensory Perception of Food • Taste and Smell • Palatability • Pet Obesity & Sensory Systems

4. Central Thesis I • Compared with Humans and Mice and Rats and Fruit Flies… • Our knowledge of Cat & Dog Sensory Perception and Food Intake Systems is: Surprisingly Limited & Primitive! Gustation: Cats 100 papers……………..Rat @4000!

5. Central Thesis II • 2. Obesity in pets parallels human obesity and Diet and Lifestyle may be more common than dissimilar. • 3. Pet Food Perception and Pleasure is closer to Human Perception and most Pet Food is “Dismally Dreary”

6. Human Sensory Systems • Tremendous explosion of taste & smell science • Nobel Prize for Physiology to Linda Buck • Olfaction & Receptors • Palatability theories • Gut-brain connection • Obesity implications

7. Sensory Homunculus-Human • 40% of all sensation from the mouth and face • Intestines about 5% of sensation Sensation Intestines

8. Human Diet Evolution • Salt, fat and sugar scare in Past! Lean meats, berries, whole grains, vegetables, fruits, honey Thrifty Gene Hypothesis

9. Humans are “Cookivores” • Wrangham hypothesis: • Humans evolved with fire 2 million years ago: vision enlarged, noses shrank • Aroma receptors down but connections increased dramatically (3 Olfactory Brains) • Aromas associated now with: • Cuisine • Fire • Fermentation

10. Human Sensory Systems • “Cookivore” Theory • Human sensory systems co-evolved with the use of fire • Evolutionary Past • Omnivores (Dietary flexibility) • Like Caloric Density • Grains, Sugars, Fatty Meats rare • Complex Palatability Brain wiring • Five Basic Senses is obsolete concept • Died with Aristotle

11. Human Gustation • Sense of Taste more Complex • Up to Eight Basic Tastes or Sensations • Umami Receptor • Two Forms—unique interactions • MSG versus 5’ Nucleotides • Signals for Protein in Environment • Sweet taste combined with fat “lightup” the brain! • Unilever: Ice Cream

12. Photos courtesy of Linda Bartoshuk, Ph.D. Yale. Illustration by Lydia Kibiuk. Supertasters Supertasters have higher number of Taste buds…foods In general are too intense for these folks. Beware of these People in taste panels

13. Human Olfaction • 3% Human Genome • 1000 Gene-Olfactory Receptors • Finely tuned—some react to just a few aromas • 40% Pseudogenes! • Degenerating over last 50,000 years • “No” degeneration in other species • Higher order connections more complex than any other species! Secondary and tertiary olfactory brains! DOG and CAT more Direct!

14. Exquisite Sensitivity • For the Skunk odorant, only about 40 receptor cells in the human nose need no more than 9 molecules to give a detectable odor sensation • Britannica Online, (2001) • Dogs determine direction of human steps with as little as five steps. • No need to sniff…it is continuous! • Chemical Senses (2005)

15. Olfaction

16. Olfaction Brain Pathways • Aromas processed by the limbic system first! 10,000 Glomeruli 40 million receptors

17. Sensitivity vs Selectivity • Just because one species has more Olfactory Neurons doesn’t mean superiority! • Primate (macaque) species have remarkable ability to pick up carboxylic acids (e.g. propionic, heptanoic) >> than the rat or dog! • Olfactory ability: depends on 1. odorant binding protein 2. aroma desruction, 3. receptor tuning and higher order processing! • Chem. Senses 29: 101-109, 2004

18. Sensory Specific Satiety Nutritional Conditioning Food Pleasure Equation Mere Exposure Effect Food Aversions Evoked Qualities Dynamic Contrast SuperNormal Stimulus SuperTasters Human Food Palatability Theories Food Pleasure = Taste (Pleasure) + Calories (Calpaldi)

19. Cat & Dog Sensory Systems “Every Animal Lives in its own Sensory World” (Morley Kare, Monell) “ Cats Live in a Different Sensory World Than the Cat Owner” (Li et al. 2005) “Both Dogs & Cats are Pre-disposed to Detect Odors and Taste Associated with Meat” (Monell Connection Fall 2000)

20. Olfaction & Evolution • Earliest Sensory System • Advantages versus Vision/Hearing: • Works in Dark • Takes no moving parts • Long range • Found from prokaryotes to humans • Makes more connections to brain than any other sense • Odors and Memories are Special

21. Olfaction’s Major Role • Recognize Nutritious Food • Perinatal exposure to aromas increase preference in dogs • Chemical Senses 2006 31(3):207-212 • Recognize Poisonous Food • Locate Sources of Attractive Smells

22. Shaggy Dog—The Movie • Question to Tim Allen on “what is the hardest thing about being a dog? • Answer: “Being totally distracted by smells!”

23. Dog’s and Smells I • "Their world is a very complex, olfactory world. They are surrounded by a vast array of different things that we are really hardly aware of. It's full of colors. It's full of brightness, which are smells." • Dr. Donald Broom, from 60 Minutes, Jan 9th 2005 Dogs almost see the smells

24. Dog’s and Smells II • Primary Social Functions: • Individual Recognition • Maintain Affiliations • Reduce Competition • Acuity Stable Among Breeds

25. Dog and Olfaction • Human’s have 50 million primary sensory receptor cells • In Dog’s the number is onebillion! • Capable of detecting nitroaromatic compounds as low as 500 PPT. • Astonishing Directional capacity • Spatial fluctuations in odor intensity • Olfactory Epithelium larger surface area than that of the retina (Adrian, 1951) Human 10 cm2; Cat 20 cm2; Dog 170 cm2

26. Dog and Olfaction II • Greater variety of Olfactory neurons • Increased odorant detection (variety) • Greater proportion of Brain tied into olfaction than humans • James Walker in National Geographic • Dog & Human Genome similar • Share many common diseases • Ewen Kirkness • Shared Evolutionary Path???

27. Dog’s Smell out Disease Researchers say dogs can be more accurate than current cancer tests and represent a breakthrough in cancer detection. [60 minutes, 2005]

28. Dogs and Taste • Carnivores (not obligate) • Human like T1R2 receptor structure • Love Sweet carbohydrates • Select sucrose (like Humans & Rats) • Some sweets deadly—Xylitol over stimulates insulin release • Bears and Raccoons also love sweets! • Prefer MSG solutions ( pancreatic flow) Li, 2005; Torres et al. 2003

29. Bitter Taste Genetics [T2R] • More genes for Bitter than for the other tastes • Critical to avoid bitter toxic foods • >95% plant poisons bitter • Humans 25; Mice 34; Chickens 3; Dogs 15. • Go, Y. Mol Biol Evol 2006, Feb 16.

30. Drosophila & Basic Tastes • Receptors for sweet and bitter (and sour and salt) just like Cats & Dogs! Over entire body! • Prefers foods that contain amino acids and sugars and non bitter compounds—just like dogs and cats! • Have sweet receptors for trehalose and aromas tuned to yeast fermentation! • Humans have trehalase enzymes!

31. Cat Nutritional Physiology • No salivary amylase • Very high protein requirement • Small stomach, likes energy dense foods • High Taurine requirement • Only preformed Vitamin A • Need Linoleic & Arachidonic Acid (animal fat) • Can’t convert tryptophan into niacin • High L-carnitine requirement • Quirky Liver Glucokinase Strict Carnivores

32. Cat Olfaction • Novel & Unstudied Species • Similar to Human and Rat • George Gomez • Olfactory Receptors use multiple signalling (more complex) • OR broadly tuned and species-specific evolutionary adaptations • Food without smell reduces eating Chem Senses. 2005 May;30(4):317-26. Epub 2005 Mar 30

33. Cat Olfaction II • Cat aroma perception unique—due perhaps to “unique survival ability” of this species. Gomez, Chem Senses 30:1-10, 2005

34. Owners and Cat Aroma • Cat Owners have poor ability to recognize their own cat by odor alone. • 25 Cat owners, 52% could recognize them. Perception. 2002;31(4):511-2.

35. Cats & Evolution & Taste • Strict Carnivores (non-plant) • Solitary & Nocturnal (Social?) • Taste Buds responsive to amino acids • Poorly developed sodium appetite • Humans is highly developed • Shows sodium insensitivity • Not adapted for long fasting • Fat Preference? Tallow vs. Corn Oil • Dislike MCT Oil

36. Vomeronasal Organ

37. Vomeronasal Organ • Small canal lined with olfactory cells, complex epithelium • Specifically tuned to certain odors • Phermonal in nature: • Sexual, feeding, social • Separate olfactory connections • Primates mostly non-functional

38. Nepatalactone • Cats sense nepetalactone from catnip using the vomeronasal organ • Sexual Pheromone found in urine? • Nepatalactone smells like valerian extracts • Psychoactive compounds when inhaled by humans! • Found in some Curry Powders!

39. Taste vs. Smells • Taste Response are largely hardwired • Taste has Relatively high thresholds • Bitter has the lowest • Odors work at Low Thresholds • Odors Need Learning (Most) • Odors may have specific tunings based on evolutionary pressures Plastic vs. Non-Plastic Sensory Perception

40. Olfactory Tuning • Odorants Binding Proteins (OBPs) bind aromas in nose • Bovine & Pigs OBPs show broad specificity for medium sized hydrophobic compounds • Green and Floral notes (Pelosi, 1996) • MW of 160-200 Daltons • What about cats and dogs? Vincent et al. 2000

41. Billion Dollar Brands • Some Pet Food Brands Break into the Top 50 Brands Worldwide: • Friskies • Pedigree • Whiskas

42. Gourmet Dog Food • Purina Dishes: • Roasted chicken w/pasta and carrots • Del Monte Kibble & Bits: • Adding pasta and vegetables • Proctor & Gamble: • Savory Sauce, bacon, chicken & roasted beef “Humanization of Pets”

43. Pets and Taste Hedonics • Greatest pleasure is in the taste of a food— not the aroma! • Dry Cat Food: devoid of food pleasure! • Natural prey loaded with Umami Tastants • BLOOD huge hedonic tastant! • Great Idea: “Savory Sauce” • “she actually jumps on her back legs and tries to get into the bowl when she sees me with it” • Modern French Cuisine technique!!!

44. Dynamic Contrast & Pet Food • Pet Food lacks “Dynamic Contrast”—Hyde & Witherly theory of Food Palatablity. • Pet Food is “Dreadfully Dreary” • Too hard, too soft, too mushy • Nestle “came up with a process (dogs) that would provide some crunch and that wouldn’t come out mushy” WSJ 2006 • Dog’s compelled to “Novelty in Foods” • Mugford R. 1984

45. Dog & Sensory Specific Satiety • SSS=decreased hedonic response to repeated exposure to sensory properties of food. • “Dog eat more when offered two different food bowls, because of the addition of novel foods in familiar diets” • Torres (2003) • Actually, this is SSS! • Cats may also prefer Novel Foods • Stasiak (2002)

46. Pet Obesity Rate • 25-45% of pets obese • Wall street Journal, March 18th, 2006 • But Death rate has not increased! • Nutritional completeness • Antioxidant inclusions • Appears to parallel the human adult obesity rate (currently about 61% overweight-30% Obese)

47. Fat Pets; Fat People

48. Human Obesity Summary • Increased Intake (200-220 kcals/day) • Decreased Activity (10-15% less) • Tasty High Caloric Density Foods • Brain-Stomach prefers high density • Rise of Fast & Junk Foods • Many Foods “High Glycemic” • Hyperphagia • Rise of High Fructose Corn Syrup • Insulin resistance ( Leptin/ Insulin/ Ghrelin) • Food Intake System Biased Upward • 100+ neurotransmitters

49. Purina Life Span Study • 14 year Study Labrador Retrievers • Restrict Diet to Ideal Body Weight • Extended Life Span by 15% • Pet Owner’s not Likely to see Pets as being overweight • Hi Body Fat induces insulin resistance and glucose impairment (like humans) BT Larson J. Nutr. 2003

50. Obesity in Pets • Pets are fat because humans are fat • Rich food, lack of exercise • Spay/Neutering decreases energy expenditure (Kirk et al. 2000) • Unlimited food access • Dog BMR Decreases w/age; not cats • Do higher carbohydrate foods with high fat table scraps encourage fat deposition?