The recent Virtual Pet Food Forum provided some very interesting science on Grain Free and Raw Diets for pets. The following information is not an endorsement of Grain Free and/or Raw Diets; it is simply reporting on the presentation at the Virtual Pet Food Forum to provide you with the latest information on pet food feeding styles.
Dr. Brittany Vester Boler provided a very interesting presentation on Grain Free Diets for dogs and cats and Raw fed diets for dogs and cats. Dr. Vester Boler has a PhD in Animal Science (2008). Her information gives those considering a grain free or raw diet additional information based on recent science.
She defined a Grain Free Diet as one with no cereal grains; no corn, rice, sorghum, wheat or oats. It was stated that the basis that many pet owners have turned to grain free or raw diets, homemade diets, was pet owners concern of additives, preservatives and contaminants. She also listed lack of a suitable commercial diet to address a medical condition and pet food recalls as reason homemade diets have become so popular.
Another reason stated by Dr. Boler was allergies. However with respect to grain free diets, she noted that “allergies are often due to protein sources in the diet, not carbohydrates”. She provided the following list of common food allergens for dogs and cats…
Dogs Most Common Food Allergens
Beef, Dairy, Wheat, Egg, and Chicken
Cats Most Common Food Allergens
Beef, Dairy, Fish, Poultry, and Lamb
She quoted a Remillard 2008 study on homemade diets saying that nutrient imbalances, specifically calcium to phosphorous, were a concern for homemade food for pets.
Although there are no studies directly comparing a raw or grain free diet to a grain containing diet, she did quote five specific grain free diet studies comparing a high carbohydrate and low carbohydrate diet. The main source of carbohydrate in these studies was potatoes.
One dog study mentioned, Liu et al, 2009, the comparison was between lower carb versus high carb extruded (kibble) foods in adult dogs. Four cat studies were mentioned comparing high protein diets to high carbohydrate grain free diets. She stated the major finding of these studies were…
1. Lipid metabolites decreased for dogs fed low carbohydrate diet but not for adult cats.
(The major aspects of lipid metabolism are involved with Fatty Acid Oxidation to produce energy or the synthesis of lipids which is called Lipogenesis. Lipid metabolism is closely connected to the metabolism of carbohydrates which may be converted to fats. http://www.elmhurst.edu/~chm/vchembook/622overview.html)
2. Findings showed no difference in dogs, cats, and kittens blood urea nitrogen (BUN).
(A blood urea nitrogen (BUN) test measures the amount of nitrogen in your blood that comes from the waste product urea. Urea is made when protein is broken down in your body. Urea is made in the liver and passed out of your body in the urine. A BUN test is done to see how well your kidneys are working. http://www.webmd.com/a-to-z-guides/blood-urea-nitrogen)
Dr. Boler quoted from the following studies, Vester et al., 1009; Lauten et al, 2000; Vester et al, 2009 for an interesting comparison of body mass of cats fed a high protein diet versus a high carbohydrate diet (she stated no studies have been done comparing the same with dogs). All of these studies used potato as the main carbohydrate source.
Changes in body composition
2 month old kitten fed high protein diet
82.8% lean body weight, 16.8% fat body weight
2 month old kitten fed high carbohydrate diet (grain free)
87.7% lean body weight, 12% fat body weight
8 month old kitten fed high protein diet
76.6% lean body weight; 22.2 % fat body weight
8 month old kitten fed high carbohydrate diet (grain free)
76.7 lean body weight, 22.1% fat body weight
Adult cat fed high protein diet
70.4% lean body weight, 28.1% fat body weight
Adult cat fed high carbohydrate diet (grain free)
72.1 % lean body weight; 26.4% fat body weight
Typical diet that would likely contain a grain
4-5 month old kitten
81.1% lean body weight; 16.1% fat body weight
1-2 year old cat
72.9% lean body weight; 23.8% fat body weight
The following information, while lengthy, provides some very interesting science on various pet food feeding styles…
Dr. Boler quoted from the findings of the following studies…
Kerr et al., 2008. Comparative Nutrition Society proceedings. Nitrogen balance and digestibility of extruded, cooked raw, and raw diets.
Kerr et al., 2009. FASEBJj. 93:905.5
Compositional analysis and apparent macronutrient digestibility of four raw meat dietsin domestic cats
Vester el al., 2009 Zoo Biology (in press)
Beef and horse based raw diets fed to domestic cats
Measured the amount of protein in the food – then measured the amount of protein in the feces – to determine how much protein the animal was able to take in and utilize.
Crude protein digestibility in extruded diet (kibble) – 80%
(explanation: 80% of the crude protein in the diet was digested or able to be utilized by the pet)
Crude protein digestibility in all raw diets – over 90%
Fat digestibility in extruded – 90%
Fat digestibility in raw (except Elk) – 95% average
Fecal score from diets…the following explanation of measurement was used…
Score of 1 = hard dry pellets
Score of 3 = ideal feces
Score of 5 = diarrhea
(from 2008 study)
Extruded Diet fecal score 3.2
Cooked beef diet fecal score 2.9
Raw beef diet fecal score 2.8
(From 2009 study)
Raw Beef diet fecal score 2.3
Raw Bison diet fecal score 2.0
Raw Elk diet fecal score 1.8
Raw Horse diet fecal score 1.9
Fecal output in all studies was almost double with an extruded diet as compared to cooked or raw diet. However, fiber source can vary fecal score.
She stated these studies told us “cooking a raw beef based diet did not significantly alter nutrient digestibility.”
Her overall conclusions of grain free diets and raw diets…
Grain free diets are able to sustain cats during pregnancy and lactation and support growth.
Both grain free and raw diets are able to support cats at maintenance if provided as a complete diet and with proper handling of diet and feces.
In Q & A after the presentation, Dr. Boler stated that ‘comparing to kibble’ studies were funded by Natura Pet Foods, to her knowledge all other studies were not funded (by any corporation).
The presentation provided a great deal more information. Should you wish to watch it (and the other presentations), the recording will be available for the next couple of months. Visit The Virtual Pet Food Forum website at http://www.wattevents.com. You will need to register to view the presentations.
Again, the above report is not an endorsement of any brand or style of feeding. It is provided to give you some scientific information on different styles of feeding.
Wishing you and your pet(s) the best,
Susan Thixton
Pet Food Safety Advocate
Author, Buyer Beware
Co-Author Dinner PAWsible
TruthaboutPetFood.com
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