The Science Behind Grain-Free and Raw Diets for Cats

1. Brittany Vester Boler, PhD Department of Animal Sciences University of Illinois at Urbana-Champaign The Science Behind Grain-Free and Raw Diets for Cats

2. Outline • What are grain free and raw diets? • Is there a market for these diets? • What are the limitations, risks, and benefits? • What research has been done? • What future research needs are there?

3. What are grain-free and raw diets? • Grain-free diets • Contain no cereal grains • Corn, rice, sorghum, wheat, oats • Raw diets • Contain raw meat and other animal products • Must contain a vitamin and mineral mix to be a complete diet • A fiber source is often warranted

4. Types of diets

5. Basis for grain-free and raw diets Remillard, 2008.

6. Basis for grain-free and raw diets • Trends in feeding pets often follow patterns of humans • Organic • Low carb • Pets are more and more a part of the family • Anthropomorphism

7. Basis for grain-free and raw diets • Pets becoming allergic to typical pet food ingredients • BUT- allergies often due to protein sources in the diet- NOT carbohydrates Phillips-Donaldson, 2009

8. Basis for grain-free and raw diets • Owners think of pets as CARNIVORES • Want to feed them like their ancestors • What is the ancestral diet? • Feed on whole carcasses • Including offal (intestines) and what was in the intestines • Nutritionally speaking • Dogs are not TRUEcarnivores

9. Is there a market for these diets? • Based on their availability in stores, YES! Kvamme, 2007

10. Is there a market for these diets? • Pet foods labeled “Natural” have increased in number of stock keeping units (SKU) • 243 in 2001 to 651 in 2004 • Estimated to reach $1 billion in sales by 2010!! Kvamme, 2007

11. Limitations • Processing • Extrusion • Uses heat and pressure to cook the food • Starches needed for expansion of kibble • Grain-free diets difficult to extrude due to little expandable carbohydrate • Raw diet mixtures • Ingredients highly variable • Composition influenced by meat available

12. Limitations • Veterinarians ability to assess raw diets • Availability of reliable information is limited • Convincing owners that what is on the internet is not correct is difficult • Current resources • www.balanceit.com, www.petdiets.com, American College of Veterinary Nutrition (www.acvn.org), consultants Remillard, 2008

13. Risks for raw meat diets • Bacterial contamination • Bacteria on surface of meat will be mixed into the diet with grinding • E. coli and salmonella contamination most common • Depending on meat source utilized

14. Bacterial risks Bacteria in the food Bacteria can be shed in the feces as well!

15. Bacterial risks

16. Bacterial risks • 5 published studies to date evaluating different types of raw meat diets • Large variations in presence/absence as well as bacterial counts • Studies evaluated commercial and homemade diets Freeman and Michel, 2001; Joffe and Schlesinger, 2002; Weese et al., 2005; Strohmeyer et al., 2006; Finley et al., 2008

17. Raw meat diets • Goose • Venison • Tripe • Duck • Llama • Elk • Goat • Emu • Carp

18. Risks

19. Bacterial risks • 2 published studies evaluating fecal shedding of bacteria • 16 dogs fed a Salmonella-contaminated commercial raw diet • 44% shed Salmonella in feces within 1 to 7 days of feeding • 200 dogs, 40 fed raw meat diets • Led to increased risk for shedding Salmonella and E. coli Finley et al., 2007; Lefebvre et al., 2008

20. Diseases associated with feeding raw meat diets • Salmonella infection in infant from dog(Sato et al., 2000) • Salmonellosis in cats(Stiver et al., 2003) • Yersinia enterocolitica from raw pork(Fredriksson-Ahomaa et al., 2001) • Salmonella shedding in dogs(Cantor et al., 1997) • Kittens and puppies as Campylobacter carriers(Hald and Madsen, 1997)

21. Other issues for homemade diets Remillard, 2008

22. Nutrient imbalances • Puppies fed a BARF diet • 2 litters of 6 week old large-breed puppies • Fed diet from 2.5 or 3 weeks of age • Puppies were • Weak • Unable to stand or abnormal gaits • Poor bone mineralization • Due to abnormal Ca:P, and overall Ca deficiency DeLay and Laing, 2002

23. Nutrient imblances • Many raw diets and homemade diets • Emphasize balance over time • Are most important during demanding life-stages • Growth • Gestation and lactation

24. Benefits • Improved coat and skin quality? • Palatability? • Weight management? • All benefits currently based on anecdotal evidence

25. What research has been done? • Most research conducted with cats • No research directly comparing a diet with grain to a grain-free diet • Few comparing a raw diet to a commercial kibble or canned diet

26. Grain-free diets • 5 specific grain-free diet studies • Comparison of high-carbohydrate and low-carbohydrate diet • Main carbohydrate source- potatoes • Considered grain-free

27. Grain-free diet studies • 1 dog study • Liu et al., 2009. ACVIM • Comparison of lower carb versus higher carb extruded food (EVO; Natura Manufacturing )in adult dogs High-carb Low-carb Blood and free-catch urine samples 0, 2, 4, and 6 months

28. Grain-free diet studies • 4 cat studies • Vester et al., 2009. Br. J. Nutr. (In press) • Evaluation of kittens for first 9 mo of life fed high-protein or high-carbohydrate grain-free diets • Vester et al., 2009. Animal. 3:1287-1298 • Evaluation of high-protein or high-carbohydrate diets in spayed adult female cats • Vester et al. 2009. Arch. Anim. Nutr. 63:254-265. • Fecal microbial populations of growing kittens fed high- or moderate-protein diets. • Lubbs et al., 2009. J. Animal Phys. Anim. Nutr. 93: 113. • Dietary protein concentration affects intestinal microbiota of adult cats High-carb High-protein

29. Major findings • Lipid metabolites decreased for dogs fed low-carbohydrate diet, but not for adult cats • Cholesterol and triglycerides • Kittens fed HP vs. HC diet had increased lipid metabolites • Blood urea nitrogen (BUN) and creatinine • No difference in dogs, cats, or kittens • No influence on renal function

30. Changes in body composition in kittens Vester et al., 2009; Lauten et al., 2000; Vester et al., 2009

31. Carbohydrates and obesity • “Unnatural” cat diet containing high carbohydrates • Often blamed for obesity in cats • Little or no data to support this belief • Increased incidence of obesity in spayed pets • Do carbohydrates play a role in this?

32. Body weight changes Grain-free diets Grain-containing diet Vester et al., 2009; Belsito et al., 2009

33. Carbohydrates and obesity • Spayed cats fed a diet with no cereal grains (high-carb and low-carb) versus those fed a diet containing cereal grains • All cats gained weight following ad libitum food intake, regardless of diet • Cats fed high-protein gained ~1.4 kg • Cats fed moderate-protein gained ~0.6 kg • Cats fed grain-containing gained ~1.3 kg

34. Microbial ecology • Limited information on microbial ecology of large bowel in cats • Known to be heavily influenced on environment • Housing • Diet

35. Microbial changes over time Week 8: Kittens consuming milk and dam’s food Groupings by litter Vester et al. 2009

36. Microbial changes over time Week 12: Kittens consuming only dam’s diet Beginning to group more by diet Vester et al. 2009

37. Microbial changes over time Week 16: Kittens consuming only dam’s diet Clear distinction by diet Vester et al. 2009

38. Microbial changes Baseline diet contained cereal grains and similar amounts of protein and fiber as contained in the moderate-protein diet All values as CFU/g DM feces Lubbs et al., 2009

39. So, what does this tell us? • Animals have normal blood metabolites on grain-free diets • May change blood metabolites when fed grain-free diets with different macronutrient composition • Does not appear to influence incidence of obesity • Diet influences microbial changes in the feces • Changes due to dietary ingredients

40. Raw meat diet studies • 4 cat studies • Kerr et al., 2008. Comparative Nutrition Society proceedings • Nitrogen balance and digestibility of extruded, cooked raw, and raw diets • Kerr et al., 2009. FASEB J. 93: 905.5 • Compositional analysis and apparent macronutrient digestibility of four raw meat diets in domestic cats • Vester et al., 2009. Zoo Biology (in press) • Beef- and horse-based raw diets fed to domestic cats Raw meat diets

41. Diets Beef Diets Horse Diets

42. Measuring total tract nutrient digestibility Nutrients absorbed and utilized Food Intake - Fecal Output x 100 Food Intake

43. Crude protein digestibility a ab b ab b a b b a Kerr et al., 2008; Kerr et al., 2009; Vester et al., 2009

44. Fat digestibility c c b a b b b a a Kerr et al., 2008; Kerr et al., 2009; Vester et al., 2009

45. Nitrogen balance • Measured using a similar method to digestibility • All cats able to maintain N balance on all diets • Indicating that they were able to utilize the diet adequately to maintain muscle mass

46. Fecal score 1= hard dry pellets 3= ideal 5= diarrhea

47. Fecal microbes All values as CFU/g DM feces Vester et al., 2009

48. So, what does this tell us? • Cooking a raw beef-based diet did not significantly alter nutrient digestibility • Cats can maintain nitrogen balance on highly digestible raw meat diets • No incidence of bacterial infection

49. So, what does this tell us? • Reduces fecal output • Can lead to hard, dry feces if a proper fiber source not included • Changes in microbial ecology • Higher E. coli and C. perfringens and lower bifidobacteria than cats fed grain-containing diet

50. Raw fish diet for cats • Momoi et al., 2001. J. Vet. Med. Sci. 63:1293. • Increase in plasma lipid peroxide in cats fed a fish diet • Idea began with notable clinical cases • Increased plasma lipid peroxide • Free radicals from PUFA leak from organs into blood stream • Little known on effect of diet