ONE starting point whenever
dealing with an anxious pet is to
remind ourselves (and the owner)
that stress is a normal (and often
understandable) reaction to an
environment which is beyond the
dog or cat’s control.
The long-term aim is firstly to
appreciate normal animal behaviour,
then relate
this to the
often complex
milieu of
how the pet’s
experience
and present
circumstance
have led to a
chronic state of stress.
While stress can be protective in the
short-term (think “fight or flight”),
for extended periods the pet might
be said to enter a state of negative
apprehension.
We all appreciate that causes of
stress and anxiety are complex.
Altered living conditions (a new home,
boarding kennels/cattery or a holiday),
temporary environmental changes
(unexpected noises such as reworks,
storms, jarring music or even solitude)
or changes in routine (timing of walks
or meals) is just the start of a long list.
Particularly for cats, triggers might
include the presence of other cats,
territorial changes, con ned living
conditions, veterinary treatment/
hospitalisation or even owner stress.
This excessive chronic stress or
“anxiogenic situation” leads first to the
physiological changes we’re all familiar
with (increased heart and respiratory
rates, increased blood pressure, etc.)
before more serious imbalances occur
(shivering, alopecia, ptyalism, vomiting
and diarrhoea, for example) and then
chronic neuro-hormonal reactions
lead to behavioural changes (such as
vocalisation, altered sleeping and eating
patterns or abnormal toileting habits).
While conventional treatments
– such as behavioural therapy and
medical agents like benzodiazepines
and pheromones – can be beneficial in tackling these symptoms, nutritional
solutions should also be considered.
The right ingredients fed in the right
manner can play a very valuable role in
supporting a distressed animal.
Alpha-casozepine
One nutraceutical of great interest
is alpha-casozepine, a milk-derived bioactive peptide. The first human
studies on the anxiolytic effects of
milk originated in the 1930s, based on
the observation that “drinking milk at
bedtime makes one sleep better”. The
post-prandial calming properties of
milk are well known in the infant and
young animals (i.e. the sleeping phase
after ingestion of maternal milk).
Remember, however,
that the enzymatic
digestive process
changes in the growing
animal. Trypsin is
already active at the
time of birth, while
peptic activity only
becomes effective
when a puppy is 21
days old (Buddington, et al, 2003) for
example.
We need to take this into account
when considering using alpha-
casozepine as a nutraceutical. Research
relating to these bioactive peptides
tells us that increased bioavailability
can be achieved via tryptic hydrolysis.
This means that the casozepine parent protein requires technological
processing before it can be integrated
into a diet, to become useful to the pet.
In humans, alpha-casozepine reduces
the neuro-vegetative signs linked to
stress and the intensity of extreme
emotion; it also regulates sleep and
reduces fear reactions (Kim, et al,
2006). In the cat, alpha-casozepine has been proven to improve reactions
when interacting with strangers, signs
linked to fear (including aggression), as
well as organo-vegetative signs, often
linked to anxiety.
The anxiolytic effects tend to be
observed by cat owners from the
eighth day of administration and in
practical applications (such as moving
house, the arrival of a new pet or the
advent of show season) considerable
safety of use is demonstrated, with no
signs of side-effects (Beata et al, 2007).
Studies also show that the anxiolytic
effect of alpha-casozepine is comparable to that of diazepam (Violle
et al, 2006) but without the latter’s
side-effects. The compound renders a
benzodiazepine-like reaction, but as a
nutraceutical there is no dependence,
habituation or even rebound effect
upon changes in intake.
L-tryptophan
Another nutrient of interest is
the amino acid L-tryptophan,
the metabolic precursor of the
neurotransmitter serotonin. Early,
largely anecdotal reports linking
diet with behaviour focused on
the influence of protein (and the misconception that it causes
hyperactivity). Many studies have since
shown that the proportional presence
of L-tryptohan over other amino acid
groups leads to an increased release of
serotonin.
Tryptophan must pass from the
bloodstream into the brain to be
used as a precursor in the synthesis
of serotonin. In order to traverse
the blood-brain barrier, tryptophan competes with other
amino acids for a
carrier. Therefore,
uptake depends on the
relative presence of
tyrosine, phenylalanine,
valine, leucine and
isoleucine.
By increasing the
tryptophan:large neutral amino acid ratio, the availability
of tryptophan increases, producing
greater concentrations of serotonin.
As we know, serotonin then plays an essential role in the regulation of
mood, anxiety, appetite and sleep, thus
L-tryptophan has the properties of a
natural anti-depressant.
Studies show that dietary
supplementation of tryptophan has
promising effects on dog behaviour.
DeNapoli (in 2000) reported
behaviour-moderating effects (with
improvements in anxiety-related signs) of a diet with an increased ratio of
L-tryptophan/large neutral amino
acids.
We all know that anxiety causes
a pet, and often its owner, genuine
discomfort. As our understanding of
natural and pathological behaviour
has evolved, so have our behavioural
therapies.
Just the same as environmental
modi cations and neuro-active
medications can provide solutions
that improve the animal’s coping
abilities and increase its resistance to
stressful stimuli, so can what we put
in our pets’ bowls. The door to new
understandings in how best to feed in
stressful situations is now, thankfully,
very much open.
References and further reading
Buddington, R. K., Elnif J., Malo, Ch.
and Donahoo, J. B. (2003) Activities
of gastric, pancreatic and intestinal
brush-border membrane enzymes
during postnatal development of dogs.
American Journal of Veterinary Research 64
(5): 627-634.
Kim, J. H. et al (2006) Ef cacy of
[alpha]s1-casein hydrolysate on stress-
related symptoms in women. Eur J Clin
Nutr 61 (4): 536-541.
Beata, C. et al (2007) Effect of alpha-
casozepine (Zylkene) on anxiety in cats.
Violle, N. et al (2006) Ethological
comparison of the effects of a bovine
alpha s1-casein tryptic hydrolysate and
diazepam on the behaviour of rats in
two models of anxiety. Pharmacology,
Biochemistry and Behavior 84 (3): 517-523.
DeNapoli, J. S. et al (2000) Effect of
dietary protein content and tryptophan
supplementation on dominance
aggression, territorial aggression, and
hyperactivity in dogs. JAVMA 217 (4):
504-508.