Assessing Differences in the Quality Properties and Ultrastructure of Eggshell as Affected by Chicken Strain and Flock Age During Incubation Period

Abstract

Three hundred hatching eggs from two layer breeder flocks (Hy-Line Brown and hy-Line W-36; 150 each) were obtained at three different periods of laying cycle (early, middle and late stages). The hatching eggs were randomly taken to assess the impact of chicken strain, age, and hatching time on some eggshell measurements and structures. Results indicate that egg weight, shell percentage and shell thickness were significantly affected by strain, breeder age, and incubation time. Increasing rate of calcium absorption and utilization by the embryos during the embryonic stage clearly reflects the decrease occurred in eggshell strength. The differences of eggshell breaking strength during incubation time periods were 0.41 and 0.55 kg/cm 2 , the differences due to the incubation time may be due to the higher demand for calcium utilization in the late incubation period (18 days), observed on the10 th day of incubation. Brown eggs recorded significant higher calcium percentage in eggshell compared to the white ones. The brown breeder hens recorded significant higher total pores per egg compared to the white egg. Concerning eggshell ultrastructure, total thickness of the brown eggshell was significantly higher than those of the white eggshell by about 3.7%. All parameters, except for total thickness, were significantly affected by the interaction between strain and breeder age. Finally, we conclude that some traits including egg weight, shell percentage, shell thickness, calcium percentages in eggshell, and total pores per egg were significantly affected by strain, breeder age, and incubation time. Eggshell ultrastructure of brown egg was better compared to the white ones.

Analysis of the Physical Quality of Chicken Eggs Fed with Added Calcium Fish Oil by Spectroscopic Method

“…Eggshell quality is influenced by internal and external factors including genotype, age, laying time, cage system, and balanced feeding with adequate Ca, P and mineral supplements (Ketta & Tůmová, 2016). Calcium supplementation is the key to eggshell quality, because each eggshell contains up to 3 g of Ca, so chicken feed must contain Ca in sufficient quantities and be used efficiently (Bartter et al, 2018;Rayan et al, 2022). The physical quality of the eggshell such as shell thickness, shell hardness index and shrinking the pores of the eggshell so as to protect the egg contents (Alig et al, 2023).…”