Prenatal auditory stimulation induces physiological stress responses in developing embryos and newly hatched chicks.

Prenatal stress may evoke considerable physiological consequences on the developing poultry embryos and neonates. The present study aimed to determine prenatal auditory stimulation effects on serum levels of ceruloplasmin (CPN), alpha-1-acid glycoprotein (AGP), corticosterone (CORT), and heat shock protein 70 (Hsp70) regulations in developing chicken embryos and newly hatched chicks. Hatching eggs were subjected to the following auditory treatments; 1) control (no additional sound treatment other than the background sound of the incubator's compressors at 40 dB), 2) noise exposure (eggs were exposed to pre-recorded traffic noise at 90 dB) (NOISE), and 3) music exposure (eggs were exposed to Mozart's Sonata for Two Pianos in D Major, K 488 at 90 dB) (MUSIC). The NOISE and MUSIC treatments were for 20 min/h for 24 h (a total of 8 h/d), starting from embryonic days (ED) 12 to hatching. The MUSIC (1.37 ± 0.1 ng/mL) and NOISE (1.49 ± 0.2 ng/mL) treatments significantly elevated CPN at ED 15 compared to the Control (0.82 ± 0.04 ng/mL) group and post-hatch day 1 (Control, 1.86 ± 0.2 ng/mL; MUSIC, 2.84 ± 0.4 ng/mL; NOISE, 3.04 ± 0.3 ng/mL), AGP at ED 15 (Control, 39.1 ± 7.1 mg/mL; MUSIC, 85.5 ± 12.9 mg/mL; NOISE, 85.4 ± 15.1 mg/mL) and post-hatch day 1 (Control, 20.4 ± 2.2 mg/mL; MUSIC, 30.5 ± 4.7 mg/mL; NOISE, 30.3 ± 1.4 mg/mL). CORT significantly increased at ED 15 in both MUSIC (9.024 ± 1.4 ng/mL) and NOISE (12.15 ± 1.6 ng/mL) compared to the Control (4.39 ± 0.7 ng/mL) group. On the other hand, MUSIC exposed embryos had significantly higher Hsp70 expression than their Control and NOISE counterparts at ED 18 (Control, 12.9 ± 1.2 ng/mL; MUSIC, 129.6 ± 26.4 ng/mL; NOISE, 13.3 ± 2.3 ng/mL) and post-hatch day 1 (Control, 15.2 ± 1.7 ng/mL; MUSIC, 195.5 ± 68.5 ng/mL; NOISE, 13.2 ± 2.7 ng/mL). In conclusion, developing chicken embryos respond to auditory stimulation by altering CPN, AGP, CORT, and Hsp70. The alterations of these analytes could be important in developing embryos and newly hatched chicks to cope with stress attributed to auditory stimulation.

Prenatal thermal stress affects acute-phase proteins, heat shock protein 70, and circulating corticosterone in developing broiler embryos and neonates.

Higher or lower incubation temperature may impose some degree of stress on developing poultry embryos. This study was designed to delineate the effects of prenatal thermal stress on serum levels of acute-phase proteins (APPs), namely ceruloplasmin (CPN) and alpha-1-acid glycoprotein (AGP), the regulation of brain mRNA levels of heat shock protein (Hsp) 70, and serum levels of corticosterone (CORT) in embryos and neonatal chicks. Hatching eggs were subjected to three thermal treatments; (i) standard optimum temperature throughout (SS: 37.8 °C and 56 % RH), (ii) heat stress for 12 h daily (HS: 40.0 °C and 56 % RH), and (iii) cold stress for 12 h daily 18 (CS: 30.2 °C and 56 % RH). The heat and cold stress treatments were imposed from the 10th to the 18th day of incubation (ED). Results showed that thermal stress had a negligible effect on hatchability rate and body temperatures of neonatal chicks. The CS treatment was detrimental to embryonic growth. The HS treatment elevated AGP (ED 16, ED 18, and post-hatch day 1), CPN (on post-hatch day 1), and CORT (ED 14). On the contrary, the CS embryos had reduced AGP (ED14, ED16, ED18, and post-hatch day 1), CPN (ED 16), and CORT (ED 14, ED 16, ED 18). The brain mRNA levels of Hsp70 were upregulated throughout the experimental period in both the HS and CS embryos and chicks. Based on these modifications, AGP, together with Hsp70 mRNA expression, could be considered effective biomarkers useful to evaluate the magnitude and the time response of embryos and neonatal chicks to prenatal thermal stress. It is concluded that developing chicken embryos have the ability to evoke APPs, Hsp70 and CORT reactions which are important to cope with thermal stress.