Severe feather pecking (SFP) in laying hen
s i
s a detrimental behavior cau
sing lo
ss of feather
s,
skin damage and cannibali
sm. Previou
sly, we have a
ssociated change
s in frontal brain
serotonin (5-HT) turnover and dopamine (DA) turnover with alteration
s in feather pecking behavior in young pullet
s (28-60 day
s). Here, brain monoamine level
s were mea
sured in adult laying hen
s; focu
sing on four brain area
s that are involved in emotional behavior or are part of the ba
sal ganglia-thalamopallial circuit, which i
s involved in ob
se
ssive compul
sive di
sorder
s. Three behavioral phenotype
s were
studied: Severe Feather Pecker
s (SFP
s), Victim
s of SFP, and Non-Pecker
s (NP
s). Hen
s (33 week
s old) were
sacrificed after a 5-min manual re
straint te
st. SFP
s had higher 5-HIAA level
s and a higher
serotonin turnover (5-HIAA/5-HT) in the dor
sal thalamu
s than NP
s, with intermediate level
s in victim
s. NP
s had higher 5-HT level
s in the medial
striatum than victim
s, with level
s of SFP
s in between. 5-HT turnover level
s did not differ between phenotype
s in medial
striatum, arcopallium and hippocampu
s. DA turnover level
s were not affected by feather pecking phenotype.
These findings indicate that serotonergic neurotransmission in the dorsal thalamus and striatum of adult laying hens depends on differences in behavioral feather pecking phenotype, with, compared to non-pecking hens, changes in both SFP and their victims. Further identification of different SFP phenotypes is needed to elucidate the role of brain monoamines in SFP.