Effects of Ascorbic Acid Injection in Incubated Eggs Submitted to Heat Stress on Incubation Parameters and Chick Quality

S Sgavioli,Jb Matos Júnior,Mffm Praes,Vs Morita,Gl Zanirato,Ic Boleli,Rg Garcia,Ll Borges

doi:10.1590/1516-635x1702181-190

Abstract

Dose-dependent positive effects on hatchability and hatchling weight have been attributed to ascorbic acid (AA) when eggs were submitted or not to intermittent heat stress during incubation. Fertile breeder (Cobb(r)) eggs were used to determine if the pre-incubation injection of AA in ovo affects the incubation and hatchling quality of egg incubated under thermoneutral or intermittent heat stress conditions. Eggs were not injected or injected with 0, 2,4, or 6% AA/100µL water and incubated at continuous thermoneutral (37.5oC) or hot (39.0oC) temperature. Eggshell temperature (EST) increased in the second half of the incubation period in all experimental groups. The EST of non-injected eggs and of those injected with water was higher when incubated at 39°C than at 37.5°C, but EST was not different among eggs injected with AA. Egg mass loss and eggshell conductance were higher in the eggs incubated at 39°C than at 37.5°C.Hatchability was lower in the eggs injected with AA. Liver and yolk sac weights were higher, whereas heart and liver weights were lower in hatchlings from eggs incubated at 39°C; however, hatchling weight was not affected by incubation temperature. The results showed that AA doses affected egg conductive heat loss and hatchability, and that they did not minimize the effects of high incubation temperature on liver and heart development.

Highlights

During in-ovo development, the chicken embryo does not control its body temperature (Wekstein & Zolman, 1967, 1969; Freeman, 1971), making it highly dependent from the air temperature inside the incubator
The present study evaluated if the intra-ovo injection of ascorbic acid (AA) before incubation affected incubation quality and hatchling quality of eggs incubated under continuous heat stress conditions or not
* p≤0.07. ** (p≤0.05). a-b, A-B:Means followed by different letters in the same column are significantly different.NSnot significant..1 body surface temperature temperature, with higher values obtained in the eggs incubated at 39°C than at 37.5°C.There was a significant interaction (p

Summary

INTRODUCTION

During in-ovo development, the chicken embryo does not control its body temperature (Wekstein & Zolman, 1967, 1969; Freeman, 1971), making it highly dependent from the air temperature inside the incubator. The onset and maintenance of embryo development requires the eggs to absorb heat from the incubator air. Incubation temperatures above that considered optimal for domestic poultry (37-38°C; Romanoff, 1960; French, 1997) negatively affect hatchability and reduce both hatchling quality The effects of the injection of AA pre-incubation of eggs incubated under continuous heat stress on embryo development and hatchling quality are not known. The present study evaluated if the intra-ovo injection of AA before incubation affected incubation quality (eggshell temperature and conductance, eggmass loss, hatchability, and embryo mortality) and hatchling quality (body weight and organ weights, and body surface temperature) of eggs incubated under continuous heat stress conditions or not

MATERIAL AND METHODS

RESULTS

Findings

DISCUSSION