The effects of cyclical higher incubation temperatures on body and organs weights,thyroid hormones and HSP70 gene expression of newly hatched broiler chicks [Yumurtadan yeni çıkmış broiler civcivlerde döngüsel yüksek ınkübasyon (kuluçka) sıcaklıklarının vücut ve organ ağırlıkları,tiroit hormonları ve HSP70 gen ekspresyonu üzerine etkileri]

The objective of present study was to evaluate the effects of cyclical higher incubation temperatures in different embryonic ages on liver hsp70 gene expression,plasma t3,t4 and triglyceride (tg) levels,hatchability,body,heart and liver weights of newly hatched chicks. for this purpose,2.700 fertile eggs (average weight,58±1 g) were obtained from arian broiler breeder at 34 weeks age. in a completely randomized design,eggs were assigned to three incubation temperature treatments at 60% relative humidity with 6 replicate per each. the treatment groups were: 1) control group that eggs were incubated at 37.6°c during incubation period,2) incubation temperature was increased to 39°c for 3 h daily at embryonic ages from 12 to 14 in treatment 1 (tt1) and 3) incubation temperature was increased to 39°c for 3 h daily at embryonic ages from 15 to 17 in treatment 2 (tt2). all above-mentioned parameters were assessed at the day of hatch. the results showed that cyclical higher incubation temperatures did not affect body and liver weights,plasma t3,t4 and tg levels (p>0.05),while heart weights of chicks in tt1 and tt2 were lower (p<0.05) than control group. furthermore,tt1 significantly increased liver hsp70 gene expression compared to the control group and tt2. it was concluded that cyclical higher incubation temperatures at embryonic ages from 12 to 14 could increase liver hsp70 gene expression with no effect on body and liver weights,plasma t3,t4 and tg levels at day-old chicks. © 2016,veteriner fakultesi dergisi. all rights reserved.