A Winn Feline Foundation Report

The School of Veterinary Medicine at the University of California

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

This is only part of the report the Winn Foundation did for IBD disorders. We posted this part of that report because it shows their important research findings on Taurine deficiency in rabbit for our ground rabbit feeders. The full report is available upon request.

“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 felines have been known to choose them as their primary prey (Molsher et al., 1999). Since felines 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 felines were used for this study – 13 males and 9 females of two age groups (7 and 20 weeks). All of the felines were neutered during the course of the study. felines 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 feline food that had been tested for its ability to sustain normal growth in normal kittens. The felines 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 felines grew so that only a small amount was left in the bowl after each meal. The felines were housed in a colony with four felines per bay, sharing litter boxes and food bowls, mimicking the situation in many catteries and multiple feline households. The kittens and adolescent felines 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 feline. Most of them also had loose stools to varying degrees, although they were outwardly healthy.

The felines readily consumed both diets, but the palatability of the raw rabbit was noticeably greater; the felines ate it more rapidly and aggressively. After one week in the study, the felines 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 felines on the rabbit diet all had formed hard stools, while the commercial diet felines had soft formed to liquid stools. These differences persisted to the end of the feeding trial. The felines 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 felines shedding pathogenic type organisms (Giardia and Cryptosporidia species) were on average slightly higher for the felines 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 felines, the sudden and rapidly fatal illness of one of the felines that were fed the raw rabbit diet for 10 months was chilling and unexpected. The affected feline was diagnosed with dilated cardiomyopathy due to a severe Taurine deficiency. Moreover, 70% of the remaining raw rabbit diet fed felines, 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.

How could a wild type diet result in Taurine deficiency? The raw rabbit diet we fed contained the minimal requirement of Taurine and was therefore not considered deficient for a highly digestible diet. However, the amount of Taurine available to the feline in a diet depends on a number of factors, such as the amount of protein, the quality of the protein, whether the diet is cooked or raw, and what other ingredients are present in the diet that might increase the amount of Taurine needed (Backus et al., 1998) (Park et al, 1999). It is also possible that bacteria in the carcass of the ground rabbits or in the intestine of the felines broke down some of the Taurine. Neither of these circumstances would be detrimental to diets containing excess levels of Taurine, but would be detrimental if the diet was borderline deficient. Vitamin E levels in our raw rabbit diet were low and this can cause the meat to lose Taurine as it is processed and ground (Lambert et al., 2001).

This study demonstrates positive and negative effects of feeding a whole ground rabbit diet for felines. The growth curves of felines on both diets were identical, indicating the raw rabbit diet supported normal growth. The single most positive aspect of the whole rabbit diet was the stool quality. felines fed the raw rabbit diet consistently had extremely firm, non-odorous and well formed stools. By comparison, felines fed the commercial feline food never had stools as well formed, and usually had stools ranging from unformed to soft-formed. However, the reason(s) for the differences in stool consistency of the respective diets is unknown. felines fed the raw rabbit diet appeared to have better quality coats, something already claimed by feline breeders feeding horsemeat supplements. The most negative aspect of feeding the raw rabbit diet exceeded all of the positive attributes, however. The raw rabbit diet should have been balanced, but nevertheless caused severe Taurine deficiency over time in all of the felines fed this diet. Taurine deficiency not only affects the heart, but also the reproductive health of queens and viability of fetuses and kittens. “