Effect of timing of acclimation of broiler breeder eggs during incubation on embryo and chick development.
Bildiriler > Tam Metin Bildiri
Yazarlar: E. Babacanoğlu, Hüseyin Cem GÜLER, Zişan Servet YALÇIN
EPC 2006 - 12th European Poultry Conference, Verona, Italy, 10-14 September, 2006., , , Uluslararası, Tam Metin Bildiri
Özet
Thermotolerance of broilers can be altered by acclimation of embryos during critical stages of the incubation. The purpose of the present study was to investigate the effect of acclimation time during different periods of embryogenesis on pre-hatch and chick development and chick quality. Control embryos were incubated at 37.8 °C whereas the acclimated embryos were exposed to 39.6 °C for 6 h/d from 12 to 16 d (H 12-16), 13 to 17 d (H 13-17), and 14 to 18 d (H 1418) of incubation. Eggs were removed from incubator at the end of the first day (i.e. 12, 13, 14 d of incubation) of heat treatment and at the end of the heat treatment (i.e. 16, 17, 18 d of incubation). Embryo weights and relative weights of liver, heart, and proventriculus+gizzard were determined. The timing of external pipping and hatching were recorded individually every 2 h between 424 and 490 h of incubation. At hatch, the same measurements were repeated and rectal temperature and chick length was measured and tonic immobility duration was recorded. Acclimated eggs had heavier relative and absolute embryo weight than control eggs. At hatch, chick body weights and yolk free body weights were similar among groups. Higher incubation temperature decreased relative liver weight of embryos from H 13-17 and H 14-18. At hatch, chicks from H12-16 had heavier liver weight than chicks from control while the others had similar liver weights to controls. Treatments had no effect on relative heart weight. At hatch, highest relative gizzard+proventriculus weight was found for chicks from H 12-16. Egg weight loss on d 18 of incubation was higher in the control group than heat treatment groups. These results indicated that development of embryo and chick might change due to the timing of acclimation. Heat acclimation for 5 days after the 12 day of incubation accelerated external pipping and hatching compared to the controls and affected chick quality by the means of decreased chick length and increased tonic immobility duration.