The effects of dietary oleuropein and organic selenium supplementation in heat-stressed quails on tonic immobility duration and fluctuating asymmetry

Abstract

The current study aimed to compare the effects of the dietary supplementation of oleuropein (O) alone or with organic selenium (OSe) in combination with the dietary supplementation of α-tocopherol acetate alone (TA) or with OSe in combination on tonic immobility (TI) duration and fluctuating asymmetry in Japanese quails exposed to heat stress (HS) (34 °C). A total of 800 two-week old quails were kept in wire cages in a temperature-controlled room at either 22 °C (thermo-neutral, TN) or 34 °C (HS) for 8 h/d and fed on a basal diet (NC) or the diets supplemented with TA (TA200) or O (O200) at 200 mg/kg alone or with OSe (TA200 + OSe and O200 + OSe) to the NC diet. HS increased TI (p < .001) and the lengths of the beak, outer toe, eye and nostril (p < .05) of quails. On the other hand, feeding diets containing TA200 alone or with OSe and O200 with OSe significantly shorted the TI duration and decreased the nostril length of quails exposed to HS compared to those of quails fed the NC and O200 diets (p < .05). It can be suggested that the TI and the asymmetry value are a sensitive indicator of thermal stress’ effect in quails. Moreover, the present study showed that especially the O200 + OSe diet may similarly alleviate the negative effects of HS on TI and mean bilateral asymmetry value of the nostril length in quail compared to the TA200 and TA200 + OSe diets.