Saudi native chicken response to embryonic thermal manipulation: Comparative morphometric analysis of myofiber diameter of the pectoral and thigh muscles.

BACKGROUND

Native Saudi chickens have the genetic capacity to develop well and produce eggs in hot environments, allowing them to withstand heat stress. Thermal alteration is one of the most significant strategies to genetically improve muscle growth and growth performance during embryogenesis.

AIM

This study assessed the impact of temperature on the hatchability, body weight (BW), and myofiber diameter of the pectoral and thigh muscles of native Saudi chickens.

METHODS

In this study, 300 viable eggs were equally divided and randomly divided into three groups. The control group was maintained at 37.8°C with 56% relative humidity (RH). The other two groups thermomodulated (TM1 and TM2) were subjected to temperature manipulation and kept at 39°C for 18 hours daily at 65% RH during the embryonic days (ED 4-7 and ED 7-10, respectively. Changes were identified by analyzing paraffin slices of the thigh and pectoral muscles.

RESULTS

The hatchability rate was somewhat higher in the TM1 and TM2 groups than in the control group, but there was no appreciable shift in the embryonic BW. The TM2 group had a significantly higher BW on post-hatch days 10 and 15 than the TM1 and control groups. Furthermore, compared with the TM1 and control groups, the TM2 group's pectoral and thigh myofiber diameters were considerably more significant. Thus, without negatively impacting the hatchability rate or embryonic BW, the morphometric outcomes of the TM2 pectoral and thigh muscles during ED 7-10 increased the sensitivity of the pectoral and thigh muscles to heat stress. Gene expression analysis revealed that heat shock proteins were more highly expressed in the TM1 thigh muscle than in the control group, with heat shock proteins (Hsp)70 showing a higher expression than Hsp60, Hsp90, and Hsp108. In contrast, there was no appreciable change in the mRNA expression of Hsp60, Hsp70, and Hsp108 in the thigh muscle when TM1 was heated in the ED18 group.

CONCLUSION

Thus, commercial breeders can use thermal manipulation to improve the muscle growth of local chickens in the Kingdom of Saudi Arabia.