Taurine deficiency in ground diets
I have no issues with feeding ground food to cats but only as a way to transition them onto whole food (like a bone in chicken breast, a rabbit leg quarter, etc) or whole prey (such as the whole mouse, quail, rat, etc). The reason for this is that ground food, especially whole prey (intestinal bacteria further oxidize taurine) that is ground is deficient in taurine, enough to cause health problems and even death. This study is what I am referring to. Keep in mind this is not a study showing that rabbit meat, a raw diet or whole prey is improper, it is actually showing that ground and ground whole prey is improper.
A Winn Feline Foundation Report On ...
Role of Diet in the Health of the Feline Intestinal Tract and in Inflammatory Bowel Disease
Investigators: Angela G. Glasgow, DVM; Nicholas J. Cave, BVSc, MACVSc; Stanley L. Marks, BVSc, PhD, Dip. ACVIM (Internal Medicine, Oncology), Dip. ACVN; Niels C. Pedersen, DVM PhD, Center for Companion Animal Health,School of Veterinary Medicine, University of California, Davis, California
The remainder of this report is a summary of our attempts to create a "gold-standard" natural diet for cats. After some thought, we decided on a diet made up entirely of rabbit. Rabbits were readily obtained from a rabbitry producing meat for human and exotic animal consumption, and were of comparatively low cost. Mice may have been more appropriate, but procuring and processing this number of mice was not practical. Moreover, in places where rabbits are abundant, feral cats have been known to choose them as their primary prey (Molsher et al., 1999). Since cats eat most parts of their prey and essential nutrients are concentrated in different organs, the rabbits were not skinned, dressed or cleaned, but rather ground in their entirety. The ground whole rabbit diet was frozen in smaller batches and thawed prior to feeding.
Twenty-two purposefully bred cats were used for this study – 13 males and 9 females of two age groups (7 and 20 weeks). All of the cats were neutered during the course of the study. Cats were randomly assigned to one of two groups according to age and gender; one group was fed our raw rabbit diet and the second group was fed a premium brand of commercial cat food that had been tested for its ability to sustain normal growth in normal kittens. The cats were fed free choice with new food placed in their bowls twice daily to ensure that the food was always fresh. The amount of food was continually increased as the cats grew so that only a small amount was left in the bowl after each meal. The cats were housed in a colony with four cats per bay, sharing litter boxes and food bowls, mimicking the situation in many catteries and multiple cat households. The kittens and adolescent cats used in this study originated from a breeding colony that was known to have a number of common intestinal pathogens. Indeed, several different common intestinal pathogens (Cryptosporidia, Giardia and Campylobacter species) were present in the stools of virtually every cat. Most of them also had loose stools to varying degrees, although they were outwardly healthy.
The cats readily consumed both diets, but the palatability of the raw rabbit was noticeably greater; the cats ate it more rapidly and aggressively. After one week in the study, the cats on the rabbit diet all had significant improvements in their stool quality based on a visual stool grading system (developed by the Nestlé-Purina PetCare Company). After one month, the cats on the rabbit diet all had formed hard stools, while the commercial diet cats had soft formed to liquid stools. These differences persisted to the end of the feeding trial. The cats that were fed the whole rabbit diet outwardly appeared to have better quality coats, but objective measurements were not made. Interestingly, we could find no relationship between the type of diet consumed and: 1) the rate of growth, 2) degree of inflammation in the tissue lining the intestinal tract, or 3) the numbers of bacteria in the upper small intestine. The numbers of cats shedding pathogenic type organisms (Giardia and Cryptosporidia species) were on average slightly higher for the cats that were fed the raw diet. Therefore, it appeared that the raw rabbit diet did not have its beneficial effects on stool quality by reducing pathogenic organisms in the intestine, altering the numbers of bacteria in the small intestine or by diminishing the levels of inflammatory changes in the intestinal wall.
Although it appeared that the raw rabbit diet was significantly beneficial for the stool quality and appearance of health in the cats, the sudden and rapidly fatal illness of one of the cats that were fed the raw rabbit diet for 10 months was chilling and unexpected. The affected cat was diagnosed with dilated cardiomyopathy due to a severe taurine deficiency. Moreover, 70% of the remaining raw rabbit diet fed cats, which appeared outwardly healthy, also had heart muscle changes compatible with taurine deficiency and could have developed heart failure if continued on our raw rabbit diet. For the remaining three months of the study, the raw rabbit diet was supplemented with taurine and taurine levels returned to normal.
Alright, so we have that out of the way. You may now be asking "how can we know for sure that grinding causes taurine loss?" Good question! I shall show you something.
Taurine (2-aminoethanesulfonic acid) is a derivative of a sulfur containing amino acid called cystine. If you have lower levels of cystine, you inevitably have lower levels of taurine. This is useful in determining how grinding and bacteria can affect the levels of taurine in food, since the USDA does not measure it in the food database.
Cystine level in chicken, ground, raw is recorded as .188 grams per 100 grams
Cystine level in chicken, broilers or fryers, meat only, raw is recorded as .274 grams per 100 grams
Cystine level in pork, fresh, ground, raw is recorded as .215 grams per 100 grams
Cystine level in pork, fresh, sirloin, boneless, raw is recorded as .261 grams per 100 grams
Cystine level in rabbit, wild, raw is recorded as .274 grams per 100 grams
Cystine level in rabbit, domestic, composite of cuts, raw is recorded as .252 grams per 100 grams
Rabbit contains the same levels of cystine as chicken, and more than pork (wild rabbit does). Not likely that the rabbit meat (before it was ground) used for the study was deficient in taurine and as you can see, all ground meats are lower than their whole counterparts in cystine. I do not have a figure for ground rabbit, but seeing the emerging trend, I would bet it would be lower in cystine in ground form. You may do your own comparisons of different meats by going to The USDA National Nutrient Database and using the search function.
has some great charts that show the levels of taurine in certain raw foods.