Comparison between different breeds of laying hens in terms of eggshell translucency and its distribution in various ends of the eggshell

Abstract

Eggshell translucency is a ubiquitous external eggshell quality problem caused by variations of eggshell ultrastructure or shell membrane. In previous studies, researchers have widely investigated this phenomenon with nutritional, environmental, and genetic perspectives in many breeds. However, most studies referring to phenotypic measurement of shell translucency have been performed using a relatively subjective two-, three-, or four-grading methods, which made it impossible to compare distribution of shell translucency among different breeds. In this study, we aimed to explore variations of translucent eggshell spots in different breeds and their distribution in blunt, middle, and sharp ends of eggshell using a relatively objective grayscale recognition method. We selected 45 eggs from each flock of pure lines, commercial strains, and Chinese local breeds (10 flocks, aged 60 to 70 wk), and stored them in a constant environment for 5 d. Then measured eggshell translucency using grayscale recognition method. Indicators of shell translucency included sum of spot areas on the whole eggshell ( SUSA ), sum area of the whole eggshell ( SUSHA ), RSS (ratio of SUSA to SUSHA ), quantity of spots ( QS ), average spot area in eggshell ( AAES ), and diameter of spots in eggshell ( DS ). As results, in Hy-Line Brown, Brown-Egg Dwarf Layer, and Taihang (pink-shelled) breeds, phenotypic intensity of eggshell translucency was slight; in Rhode Island Red, Jingfen-1, and Dongxiang breeds, phenotypic intensity of eggshell translucency was relatively extensive; and in Jinghong-1, Hy-Line Sonia, White Leghorn, and Taihang (blue-shelled), phenotypic intensity of eggshell translucency was at an intermediate level. In general, the larger the RSS, the larger the QS, AAES, and DS. Of 3 ends for most breeds, eggshell translucency of blunt and sharp ends was usually greater than that of middle ends, and blunt ends seemed to have the most extensive eggshell translucency. Findings from this study could provide a reference for population selection to locate genes regulating shell translucency and to explore the physical structure mechanism for eggshell translucency formation.

Eggshell translucency: its relationship with specific gravity and eggshell color and its influence on broiler egg weight loss, hatchability, and embryonic mortalities

“…In recent years, much research has been conducted on eggshell translucency, especially with respect to the characteristics, incidence, influencing factors, and impact of this abnormality on table eggs ( Leach and Gross, 1983 ; Chousalkar et al, 2010 ; Wang et al, 2017 ; Wang et al, 2019 ; Wong et al, 2020 ; Zhang et al, 2021 ; Ren et al, 2023 ). However, despite the belief that eggshell translucency can affect incubation and hatching parameters, concrete data are scarce ( Galindo et al, 2022 ; van den Brand et al, 2023 ).…”

Effects of trace minerals source in the broiler breeder diet and eggshell translucency on embryonic development of the offspring

“…However, in the latter study, flocks of >65 wk of age showed comparable translucency scores than the younger flocks. Baker and Curtis (1957) and Zhang et al. (2021) showed that egg translucency differed between white leghorn strains and Baker and Curtis (1957) showed that egg translucency largely varied between individual hens, and eggs of the same hen showed less variability in translucency.…”

“…Recently, Wang et al. (2017 , 2019a ) and Zhang et al. (2021) investigated effects of egg translucency in relationship to other egg characteristics.…”

Eggshell translucency in late-phase laying hens and its effect on egg quality and physiological indicators

“…Traits of shell translucency are partly regulated by genetic factors, manifesting in differences in the severity of shell translucency among strains and between individuals. Furthermore, hens have laid eggs with the same level of translucency on consecutive days ( 3 , 6 ). In previous studies, the heritabilities of eggshell translucency were estimated to be 0.18–0.22 in 63-wk-old Brown-Egg Dwarf Layers and a 52-wk-old F 2 resource population generated from a cross between Dongxiang Blue-shelled and White Leghorn hens ( 2 ).…”