The genetic of behaviour: correlation between tonic immobility test and hepatic glucocorticoid receptor nr3c1 in a slow growing chicken breed

The aim of this research is to evaluate the correlation between phenotypic evaluation of behavior (fear; Tonic Immobility test: TI) and gene expression by absolute RT-PCR (Glucococrticoid Recepror NR3C1: GR) in a traditional Italian slow growing chicken breed: Valdarnese Bianca. A total 50 birds were analyzed (sex ratio 1/1; 15 birds/m, litter floor, standard rearing procedure, slaughtering: 85doa), every bird was tested for TI at 80doa (max 3 inductions (N), max 3 min latency(s)). GR mRNA levels were analyzed using one-tube, twotemperature real-time PCR for absolute quantification of the gene expression by the standard curve method. Data were analyzed using SAS® software (ANOVA, CORR), birds sex was the source of variation. Our results show no significant different in GR expression, TI number induction and latency duration according to birds sex. The correlation analysis show significant results (P≤0.05) for TI latency duration and GR expression levels, an indirect correlation were calculated. Latency duration in TI is directly correlated to stress level, so, according to corticosterone results too, a negative correlation between stress level/coping ability indicators and NR3C1 gene expression was found.