Taurine Abstracts:
Part 1, Taurine and Cats:
Diet, Reproduction & Development, Heart Failure

 

Dietary antibiotics decrease taurine loss in cats
fed a canned heat-processed diet.

J Nutr 1996 Feb;126(2):509-15
Kim SW, Rogers QR, Morris JG
Department of Molecular Biosciences, School of Veterinary Medicine,
University of California-Davis 95616, USA.

In a crossover design, cats were fed a canned heat-processed
diet (18 g dry matter/kg initial body wt) either with (+) or
without (-) antibiotics [a mixture of penicillin G, procaine
25 mg/18 g diet) and tetracycline (50 mg/18 g diet)].
The (-/+) group received no antibiotics during the first 5-wk
period and received antibiotics during the second 5-wk period;
the (+/-) group received the reverse. Plasma, whole blood,
urinary and fecal concentrations of taurine, fecal bile acid excretion and
cholyltaurine hydrolase activities were measured.
Consumption of antibiotics for 5 wk resulted in a lower rate of depletion of
plasma taurine. Taurine concentrations decreased more over the first 5 wk in
cats in the (-/+) group than in cats in the (+/-) group [from 116 +/- 26 to 26
+/- 6 mumol/L (-/+) and from 109 +/- 6 to 77 +/- 7 mumol/L (+/-) for plasma, and
from 546 +/- 8 to 292 +/- 29 mumol/L (-/+) and from 560 +/- 11 to 431 +/- 20
mumol/L (+/-) for whole blood]. Urinary total taurine excretions during the 5th
week were 54 mumol/d for the (-/+) group and 135 mumol/d for the (+/-) group
(pooled SEM, +/- 13). Fecal total taurine excretions during the 5th week were
184 and 53 mumol/d for the (-/+) and (+/-) groups, respectively, (pooled SEM +/-
9). Most of the fecal taurine was unconjugated (free). Fecal bile acid
excretions during the 5th week were 235 +/- 18 and 106 +/- 11 mumol/d for the
(-/+) and (+/-) groups, respectively. Dietary antibiotics suppressed fecal
cholyltaurine hydrolase activity of cats. Fecal cholyltaurine hydrolase
activities during the 5th week were 279 +/- 54 and 42 +/- 10 nmol cholic acid
released.min-1.g dry feces-1 in the (-/+) and (+/-) groups, respectively. After
the crossover, mean values for the groups were reversed, showing that the
observed changes were due to the antibiotic treatment. These results support the
hypothesis that the dietary taurine requirement of cats is largely determined by
the extent of microbial degradation of taurine in the gastrointestinal tract.

 

Maillard reaction products in purified diets induce
taurine depletion in cats which is reversed by antibiotics.

J Nutr 1996 Jan;126(1):195-201
Kim SW, Rogers QR, Morris JG
Department of Molecular Biosciences, School of Veterinary Medicine, University
of California, Davis 95616, USA.

The effects of heat processing (Maillard reaction) and addition of antibiotics
to diets on the metabolism of taurine in adult cats were studied. Groups of four
cats were given daily 22 g/kg body weight one of four purified diets based on
casein and starch. All diets contained the same major ingredients as the control
(diet 1), except for starch substitutions. Diet 2 was autoclaved; in diet 3, 50
g glucose replaced 50 g starch before autoclaving; in diet 4, only the casein
component was autoclaved with 50 g glucose before addition to the diet. Diets
were fed for 5 wk, then a mixture of antibiotics was added to all diets and they
were fed for a further 5 wk. In the first (no antibiotics) period, cats given
the Maillard reaction products (diets 3 and 4) had a significant depletion of
plasma and whole blood taurine and had twice the fecal, but less than half the
urinary total taurine excretion of control cats. The addition of antibiotics to
the diets restored plasma and whole blood concentration in cats given diets 3
and 4, reduced fecal and increased urinary taurine excretion, and decreased
fecal cholyltaurine hydrolase activity. These results suggest that Maillard
reaction products promote an enteric flora that favors degradation of taurine
and decreases recycling of taurine by the enterohepatic route.

 

Dietary soybean protein decreases
plasma taurine in cats.

J Nutr 1995 Nov;125(11):2831-7
Kim SW, Morris JG, Rogers QR
Department of Molecular Biosciences, School of Veterinary Medicine, University
of California, Davis 95616, USA.

Commercial dry and canned diets fed to cats cause approximately two- and
fourfold increase in the taurine requirement, respectively, as compared with
that observed for purified diets. In two experiments, the effect of source and
level of protein and fiber in the diet on the concentration of taurine in plasma
and whole blood of cats was studied. All diets contained 1 g taurine/kg dry
matter. When a casein-based diet containing either 25% or 50% protein was given
to cats for 6 wk, no difference in plasma taurine concentration was observed;
however, substituting soybean protein for casein resulted in a significant (P <
0.01) decrease in plasma taurine concentration of cats in the 50% soybean
protein group, but not in the 25% soybean protein group. In Experiment 2, the
food intake of cats was limited [26 g dry matter/(kg body weight.d)], and the
protein was 30 or 60% of the diet. Cats fed 60% soybean protein or casein diets
had significantly lower plasma taurine concentrations than cats fed a 30% casein
diet, with the 60% soybean protein diet causing the greater decrease. There was
no effect of either 2 or 4% soybean fiber on plasma taurine concentration as
compared with the same diet without the added fiber. The taurine concentration
in plasma was higher (P < 0.05) in male cats than in female cats. Protein
source, amount in the diet and gender did not affect the whole blood taurine
concentration. Cats given diets containing 60% casein or soybean protein diets
excreted a greater amount of fecal total bile acid and total taurine than cats
given a 30% casein diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Fecal bile acid excretion and taurine status in cats fed canned and dry diets.

J Nutr 1994 Dec;124(12 Suppl):2546S-2551S
Anantharaman-Barr G, Ballevre O, Gicquello P, Bracco-Hammer I, Vuichoud J,
Montigon F, Fern E
Nestec Ltd. (FRISKIES Research), Lausanne, Switzerland.

Cats conjugate their bile acids with taurine but are unable to synthesize
sufficient quantities of this amino acid to meet their needs. To maintain the
same blood taurine level, canned foods must contain more taurine than dry foods.
In the present study we examined the effect of soluble fiber on fecal bile acid
excretion and taurine status and compared the quantity and profile of fecal bile
acids in cats fed canned and dry diets. In a cross-over design, 10 adult cats
were fed a typical canned diet containing 0.25% kappa carrageenan with or
without the addition of 0.5% guar gum (2.5% on a dry matter basis) for 6 wk. All
cats were then transferred to a dry diet. The addition of guar gum to the canned
diet had no significant effect on taurine status, but the dry diet, which
contained less taurine than the canned diet, resulted in an increase in plasma
taurine. With the dry diet, total bile acid excretion was reduced by
approximately 65%. The profile of bile acids in feces was also radically
different with a marked decrease in secondary bile acids. This work suggests
that when canned rather than dry diets are fed, the conversion of primary to
secondary bile acids is greater and is indicative of an alteration in the
activity of the gut flora that may lead to an increase in taurine degradation.

Microbial degradation of taurine in fecal cultures from cats given commercial and purified diets.

J Nutr 1994 Dec;124(12 Suppl):2540S-2545S
Backus RC, Rogers QR, Morris JG
Department of Molecular Biosciences, School of Veterinary Medicine, University
of California, Davis 95616.

Freshly passed feces were collected from cats (n = 5-7) given cooked and
uncooked commercial canned-type diets, casein and soy protein containing
purified diets and a commercial extruded diet. The feces were anaerobically
cultured in medium containing either taurine, taurocholic acid or [2-3H]taurine
for 24 h at 37 degrees C. Taurine degradation in cultures was greatest for
cultures from cats receiving diets reputed to cause taurine depletion.
Diaminopimelic acid in feces indicated that differences in taurine degradation
rate among groups was associated with differences in bacterial numbers in feces.
After 6 h of incubation, < 10% of taurocholate and > 60% of taurine remained.
Nearly all the tritium on the labeled taurine was recovered as water. These
results indicate that deconjugation and deamination are the initial steps in
microbial catabolism of taurocholic acid and that enteric microbial growth may
be a major determinant of dietary taurine requirement of cats.

 

Taurine balance is different in cats fed purified and
commercial diets.

J Nutr 1992 Mar;122(3):553-9
Hickman MA, Rogers QR, Morris JG
Department of Physiological Sciences, School of Veterinary Medicine, University
of California, Davis 95616.

Ileal fluxes, urinary losses and taurine balance were determined in six
taurine-replete and four taurine-depleted cats. Digesta samples collected at the
terminal ileum were used to assess ileal flux of taurine. Four diets were
tested: a commercial diet in two forms (heat-processed and frozen) and two
purified diets containing either 1225 or 0 mg taurine/kg diet. Five-day balance
trials were performed on d 3-7 with measurement of food intake and taurine in
urine and ileal digesta. Substantially greater quantities of total taurine (free
+ bound) were found in ileal digesta from cats fed the heat-processed rather
than the frozen preserved diet (205 vs. 101% of the average daily taurine
intake, respectively), with calculated taurine balances of -609 vs. -212
mumol/d, respectively. The quantity of taurine in ileal digesta from
taurine-replete cats fed the 1225 or 0 mg taurine/kg purified diets was not
significantly different, indicating that taurine found at the terminal ileum is
mostly of endogenous origin. Taurine-depleted cats had significantly lower
amounts of taurine in ileal digesta, with a taurine balance of -77 mumol/d.
These results demonstrate that a heat-processed diet causes substantially
greater losses of taurine from the intestine than does a frozen diet. This
phenomenon may explain the inability of some heat-processed diets to maintain
normal plasma taurine concentrations in cats.

 

Taurine in the developing cat: uptake and release
in different brain areas.

Neurochem Res 1994 Jan;19(1):77-82
Saransaari P, Oja SS
Department of Biomedical Sciences, University of Tampere, Finland.

Taurine is an important modulator of neuronal activity in the immature brain. In
kittens, taurine deficiency causes serious dysfunction in the cerebellar and
cerebral visual cortex. The processes of taurine transport in vitro were now
studied for the first time in different brain areas in developing and adult
cats. The uptake of taurine consisted initially of two saturable components,
high- and low-affinity, in synaptosomal preparations from the developing
cerebral cortex and cerebellum, but the high-affinity uptake component
completely disappeared during maturation. The release of both endogenous and
preloaded labeled taurine from brain slices measured in a superfusion system was
severalfold stimulated with a slow onset by depolarizing K+ (50 mM)
concentrations. K+ stimulation released markedly more taurine from the cerebral
cortex, cerebellum and brain stem in kittens than in adult cats. The responses
were largest in the cerebellum. Both uptake and release of taurine are thus
highly efficient in the brain of kittens and may be of significance in view of
the vulnerability of cats to taurine deficiency.

 

High dietary taurine effects on feline tissue taurine
concentrations and reproductive performance.

J Nutr 1992 Jan;122(1):82-8
Sturman JA, Messing JM
Department of Developmental Biochemistry, New York State Office of Mental
Retardation and Developmental Disabilities, Staten Island 10314.

The reproductive performance and outcome of kittens was determined for female
cats fed 0.05, 0.2 or 1% taurine. No adverse effects of high taurine diets were
noted in the adults or offspring, and the reproductive performance was slightly
better than that of females fed the normal (0.05% taurine) diet. Body weight at
birth and brain weight at weaning were significantly greater in the very high
taurine group than in the normal taurine group, although the greatest growth
rate was achieved by the normal taurine group. The concentration of taurine in
milk of lactating females was substantially higher in cats fed the higher
taurine diets. Brain of adult cats was resistant to increases in brain taurine
concentrations, as was brain of newborn cats. However, brain of juvenile cats
responded to higher dietary taurine intake with increased taurine
concentrations. These results indicate that the higher taurine content in cat
foods recently introduced for prevention of feline dilated cardiomyopathy should
have no adverse effects over a prolonged period on health and reproduction of
cats.

 

Pregnancy failure in cats associated with long-term
dietary taurine insufficiency.

J Reprod Fertil Suppl 1993;47:457-63
Dieter JA, Stewart DR, Haggarty MA, Stabenfeldt GH, Lasley BL
Department of Reproduction, School of Veterinary Medicine, University of
California, Davis 95616-8542.

The effect of long-term dietary taurine insufficiency on reproductive function
was studied in adult female domestic cats (n = 11). Cats were time-mated during
taurine-deficient (6 months) and refed (6 months) states, and the outcome of
ovulatory cycles and breeding was analysed. Serum progesterone and relaxin
concentrations were evaluated in order to characterize pregnancies, including
those resulting in resorption of fetuses, and pseudopregnancies. Increased
resorption of fetuses, reduced litter size, and increased incidence of stillborn
kittens was observed in queens while on taurine-deficient diets, as well as
after refeeding of a taurine-enriched diet. Overall, 30% of the ovulatory cycles
resulted in the delivery of kittens, with mean live and stillborn litter sizes
of 2.2 +/- 0.4 and 0.8 +/- 0.4 kittens (mean +/- SEM), respectively. The
remaining ovulatory cycles resulted either in pregnancies in which fetuses were
resorbed (38%), or in pseudopregnancies (32%). Ovulatory cycles resulting in
resorbed fetuses were characterized by the appearance of relaxin on day 20 of
gestation, but with a subsequent decrease to non-pregnant concentrations by day
25 of gestation. These results suggest that reproductive failure in domestic
cats exposed to long-term nutritional taurine deficiency is associated with a
postovulatory defect manifest within the first 10 days after implantation, and
that this defect is not reversible upon refeeding of a taurine-enriched diet for
6 months.

 

Echocardiographic evidence for myocardial failure
induced by taurine deficiency in domestic cats.

Can J Vet Res 1994 Jan;58(1):6-12
Novotny MJ, Hogan PM, Flannigan G
Department of Anatomy and Physiology, Atlantic Veterinary College, University of
Prince Edward Island, Charlottetown.

Dietary taurine-deficiency is a cause of dilated cardiomyopathy (DCM) in cats.
While the incidence of clinical cases of feline DCM has markedly decreased since
the association between DCM and taurine-deficiency was first recognized, not all
cats maintained on taurine-deficient diets develop DCM. The objective was to
temporally evaluate left ventricular (LV) function using M-mode echocardiography
in 23 cats maintained on a taurine-deficient diet; 20 time-matched,
taurine-supplemented cats served as controls. The duration of feeding trials
ranged from 6-15 months. No diminution of myocardial function was recorded in a
small number of taurine-deficient cats whereas cardiac performance in some
taurine-deficient cats diminished to levels characteristic of DCM. Of the
taurine-deficient cats, 17 (74%) experienced a greater than 25% reduction in
fractional shortening and 21 (91%) had a greater than 25% increase in LV
end-systolic short-axis diameter. On average, LV end-systolic short-axis
diameter increased by 70% and fractional shortening decreased by 37% in
taurine-deficient cats. Mean velocity of circumferential fiber shortening was
similarly reduced in taurine-deficient cats. The greatest rate of change in
M-mode echocardiographic variables occurred during the first four months on the
taurine-deficient diet. Dietary taurine deficiency leads to a spectrum of
changes in myocardial function in domestic cats. While DCM is observed in some
cats, decreased systolic pump function and increased LV end-systolic short-axis
diameter are more consistent findings.

 

Response of cats with dilated cardiomyopathy
to taurine supplementation.

J Am Vet Med Assoc 1992 Jul 15;201(2):275-84
Pion PD, Kittleson MD, Thomas WP, Delellis LA, Rogers QR
Department of Medicine, School of Veterinary Medicine, University of California,
Davis 95616.

Between October 1986 and September 1988, 37 cats with moderate to severe
idiopathic myocardial failure (dilated cardiomyopathy) were evaluated. Clinical
management of these cats was similar to that described in the literature, except
that it also included administration of 500 or 1,000 mg of the sulfur amino
acid, taurine per day. Early death (death within the first 30 days of treatment)
occurred in 14 (38%) cats. One cat was lost to follow-up evaluation. Twenty-two
cats (59%) had marked clinical and echocardiographic improvement and survived
longer than 240 days. In all but 1 cat, the observed improvement in
echocardiographic measurements persisted. Hypothermia and thromboembolism were
positively associated with an increased risk of early death. Administration of
digoxin did not significantly affect survival. All 22 cats that survived greater
than 30 days remained clinically stable despite withdrawal of all medications
except taurine. Administration of taurine was eventually discontinued in 20 of
the 22 cats and adequate taurine intake was thereafter provided for in the food.
The clinical response and 1-year survival rate of 58% (21 of 36 cats with a
known outcome) in the taurine-treated group represents a marked improvement,
compared with a 1-year survival rate of 13% (4 of 31 cats with a known outcome)
in a retrospectively evaluated population of 33 cats with dilated
cardiomyopathy.

 

Clinical findings in cats with dilated cardiomyopathy
and relationship of findings to taurine deficiency.

J Am Vet Med Assoc 1992 Jul 15;201(2):267-74
Pion PD, Kittleson MD, Thomas WP, Skiles ML, Rogers QR
Department of Medicine, School of Veterinary Medicine, University of California,
Davis 95616.

Between October 1986 and September 1988, 37 cats with moderate to severe
idiopathic myocardial failure (dilated cardiomyopathy) were evaluated
prospectively. Low plasma taurine concentration and diet history including foods
that can cause taurine deficiency were documented in most of the cats.
Comparison with a retrospectively studied population of 33 cats with dilated
cardiomyopathy diagnosed between 1980 and 1986 demonstrated that the clinical
and historical findings in the 33 retrospectively studied cats were similar to
those in the 37 cats studied prospectively. Clinical findings in the 2 groups
were also similar to findings previously reported in the literature. Because
clinical findings and diet history were similar in the prospective and
retrospective groups, we believe that many cats in the latter group had
diet-induced taurine deficiency. These findings support the conclusion that most
cases of dilated cardiomyopathy in cats have a common etiopathogenesis related
to diet and as such are preventable.

 

Taurine depletion and cardiovascular disease in
adult cats fed a potassium-depleted acidified diet.

Am J Vet Res 1992 Mar;53(3):402-5
Dow SW, Fettman MJ, Smith KR, Ching SV, Hamar DW, Rogers QR
Department of Pathology, Colorado State University, Fort Collins 80523.

Although low plasma taurine concentrations have been associated with congestive
cardiomyopathy in cats, the cause of taurine depletion in cats consuming
adequate quantities of taurine is unknown. Taurine depletion and cardiovascular
disease (cardiomyopathy and thromboembolism) developed unexpectedly in 3 of 6
healthy adult cats during a potassium-depletion study. Plasma taurine
concentration decreased significantly (P less than 0.05) and rapidly over an
8-week period (from 98 to 36 nmol/ml) in 6 cats that consumed a
potassium-deficient diet (0.20% potassium, dry matter basis) that was acidified
with 0.8% ammonium chloride, despite containing dietary taurine concentrations
(0.12% dry matter basis) in excess of amounts currently recommended. Taurine
concentrations were significantly lower in cats fed the acidified diet than in 6
cats fed a potassium-deficient diet that was not acidified (36 nmol/ml vs 75
nmol/ml) after 8 weeks. In addition, plasma taurine concentrations did not
decrease over a 6-month period in 8 cats that were fed a potassium-replete diet
with acidifier. Plasma taurine concentrations were lowest in 3 cats that died of
cardiovascular disease in the group receiving potassium-deficient, acidified
diets. These data indicated an association between taurine and potassium balance
in cats and suggested that development of taurine depletion and cardiovascular
disease may be linked to concurrent potassium depletion.

Myocardial taurine concentrations in cats with cardiac disease and in healthy cats fed taurine-modified diets.

Am J Vet Res 1992 Feb;53(2):237-41
Fox PR, Sturman JA
Department of Medicine, Animal Medical Center, New York, NY 10021.

Myocardial taurine concentrations were measured in cats with cardiac disease and
in healthy cats fed diets with various concentrations of taurine. Group 1 was
composed of 26 cats with 3 categories of naturally developing cardiac disease:
dilatative cardiomyopathy (group 1A), 10 cats; hypertrophic cardiomyopathy
(group 1B), 9 cats; and volume overload (group 1C), 7 cats. These cats had been
fed various commercial diets. Group 2 was composed of 40 healthy cats that had
been fed diets varying in taurine concentration (0 to 1% taurine) for at least 2
years. Mean myocardial taurine concentrations did not differ significantly
between group-1 cats with dilatative cardiomyopathy and those with hypertrophic
cardiomyopathy or volume overload. Cats in group 1A had a mean myocardial
taurine concentration 3 times higher than healthy cats fed a taurine-free diet
(P less than 0.002). Mean myocardial taurine concentrations did not differ
significantly between group-1A cats and healthy cats fed a diet containing 0.02%
taurine; group-1A cats had significantly lower mean myocardial taurine
concentrations than did healthy cats fed a synthetic diet containing 0.05 or
1.0% taurine (P less than 0.001). Acute oral administration of taurine in 5
group-1A cats appeared to increase mean myocardial taurine concentrations,
compared with similar cats not given taurine during treatment for cardiac
failure. In group-2 cats, mean myocardial taurine concentrations increased
directly with percentage of dietary taurine.

 

Age-associated loss of carrier-mediated intestinal
taurine transport in cats.

Nutr Rev 1993 Jan;51(1):22-3

Taurine uptake across the intestinal brush border membrane of the adult cat
seems not to be mediated by a specific transport mechanism. Therefore taurine
absorption from the gastrointestinal tract will possibly become a limiting
factor for maintenance of taurine homeostasis in the cat under conditions of
decreased dietary taurine intake.

 

Taurine Abstracts: Part 2

Taurine Abstracts: Part 3

Taurine - A Compilation by Ch. M. Ruessheim