The Effects of Different Eggshell Temperatures Between Embryonic Day 10 and 18 on Broiler Performance and Susceptibility to Ascites

A Ipek,U Sahan,A Sozcu

doi:10.1590/1516-635x1703387-394

Abstract

The aim of the current study was to determine the effects of low (33.3-36.7 ˚C), control (37.8-38.2 ˚C) and high (38.9-40.0 ˚C) eggshell temperatures (ESTs) between days 10-18 of incubation on broiler performance and susceptibility to ascites. The effects of different ESTs on hatchling weight were significant. The highest residual yolk sac weight (7.7 g) and relative yolk sac weight (18.7%) were observed in high EST group, whereas the highest yolk-free body weight (36.22 g) was obtained in the control group. Relative post-hatch heart weight was lower in the high EST group (0.64%) compared with the control (0.84%) and low (0.88%) EST groups. At 6 weeks of age, body weights of broilers of the low, control, and high EST groups were 2172.6, 2543.9, 2282.6 g respectively. During the 6-week life span, the feed conversion ratio of broilers in the low (1.86) and high (1.83) EST groups was significantly worse than of those in the control EST group (1.68). Higher packed cell volume (PCV) and red blood cell (RBC) values were obtained in the high EST group relative to the other groups, whereas hemoglobin (Hb) level was lower in the control group than in the others. The relative heart weights and right ventricular to total ventricular (RV:TV) ratio for low, control, and high EST group were 0.46, 0.40, 0.37 g and 0.27, 0.28, 0.33% respectively. In conclusion, incubation length, yolk sac absorption, residual yolk sac weight, yolk-free BW, post-hatch performance, and heart, blood parameters, abdominal fluid accumulation at slaughter age are affected by changes in EST between incubation days 10 to 18.

Highlights

Incubation is the conversion of the contents of an egg into a chicken and it is strongly affected by incubation temperature
Hatching in high eggshell temperatures (ESTs) group was completed before 26 hours, whereas hatching in low EST group was completed 10 hours after control EST group
Vieira et al (2005) observed that 90% of eggs hatched at 485 hours and that the hatchlings remained for 19 hours in the hatcher to allow the remaining 10% to hatch

Summary

Introduction

Incubation is the conversion of the contents of an egg into a chicken and it is strongly affected by incubation temperature. Incubation temperature is one of the most important factors (Molenaar et al, 2011) for embryo development and survival. The temperature within the egg, i.e., embryo temperature (Meijerhof, 2009a), is critical, and maintaining the correct embryonic temperature during incubation has been shown to be more important than incubator temperature settings (Hulet et al, 2007; Meijerhof, 2009b). French (2000) reported that even small temperature differences of 0.5 or 1oC (from 37.5 to 38.0 or 38.5oC) during the period of three to 25 days of incubation can significantly affect the embryonic development of turkeys. Several studies have shown that incubation temperature influences embryo development and post-hatch performance (Lourens et al, 2005, 2007; Meijerhof, 2009b; Molenaar et al, 2011). In studies that compared normal eggshell temperatures (approximately 37.8°C) to high shell temperatures (38.9 to 39.5°C), chick hatching weight was lower when eggs were incubated at high eggshell temperature at the end of incubation

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