New Suggested Schemes for Incubation Temperature and Their Effect on Embryonic Development and Hatching Power

摘要

The present study was to investigate two suggested schemes of incubation temperatures and their effect on hatching power and embryonic development of two local Egyptian chicken strains. Twelve hundred fertile egg (600 from each strain) were used in this experiment that distributed on the control and two suggested schemes. The traditional incubation scheme (program 1) was used as a control and fixed during incubation period (0-18 days) with 37.5 deg C and the suggested schemes incubation temperature (program 2 and 3) was 37.5 deg C from 0-14 days and then raised up to 39.5 or 40.7 deg C for 3 h daily till the 18th day (15th-17th day) for the first program and the second suggested schemes (programs 2 and 3) respectively. During the hatching period (19-21 days), the hatching temperature was 37 deg C for all three programs. Relative humidity was 55% during the incubator period for all three programs and 65% for the hatching period. Suggested programs (2 and 3) resulted in a significant increase embryoweight at 18th day of incubation and chick weight at pull out (p<=0.05) and the two programs produced chicks with a higher body weight than the program 1. There was a significant decrease in yolk sac weight in the programs 2 and 3 that associated with asignificant increase in plasma total lipid (p<=0.01). Relative liver weight was decreased significantly (p<=0.05) with increase incubation temperature at both study periods and the hepatic glycogen was taken the same trend. Plasma calcium level was increased significantly (p<=0.01) at hatching time in the two suggested programs (2 and 3) compared to the program 1 that reflected on increase tibia relative weight. A gradual and significant increase in serum T_3 concentration (p<=0.05) was found in the programs 2 and 3 compared to the control program. Increasing incubation temperature in the programs 2 and 3 caused a decrease hatching period compared to the program A, as well as the hatchability percentage (%) was increased significantly (p<0.01) and thisincrease was noticed in both the two strains.