Dataset for: Diet modulates behaviour in house sparrows: insights into possible hormone-mediated mechanisms

Foraging animals usually select foods that balance the intake of key
nutrients, for example essential amino acids that cannot be synthesized and must be obtained from the diet.
However, the ability to gain optimal ratios, proportions and amounts of
nutrients may be hampered
by a changing environment, competitive conspecifics or species and predators.
Here, we used an experimental
system in which house sparrows, Passer
domesticus, were fed a manipulated diet with different compositions of amino
acids (in the experimental diet phenylalanine and tyrosine content was 42%
of that in the control diet). Phenylalanine
and tyrosine are precursors of coping
hormones: dopamine, noradrenaline (norepinephrine) and adrenaline (epinephrine) which are involved mainly in the expression of stress and fear,
but also in learning and long-term memory formation. Accordingly, birds fed a
diet deficient in these amino acids learned to avoid unpalatable food markedly slower, coped worse with
stress in the presence of a novel object and were more aggressive towards other
sparrows than control birds. Surprisingly, circulating amounts of the
catecholamines in blood plasma were higher in these birds than in sparrows on the
control diet. This study provides
the first evidence that variation in amino acid composition in the diet is
associated with variation in behaviours and hormone levels in birds. We
conclude that food, besides its nutritional function, seems to represent
one of the modulators of behavioural expression making a balanced diet crucial
for survival.