title: In ovo sexing of chicken eggs by fluorescence spectroscopy.
abstract: Culling of day-old male chicks in production of laying hen strains involves several millions of animals every year worldwide and is ethically controversial. In an attempt to provide an alternative, optical spectroscopy was investigated to determine nondestructively in ovo the sex of early embryos of the domestic chicken. The extraembryonic blood circulation system was accessed by producing a window in the egg shell and the flowing blood was illuminated with a near-infrared laser. The strong fluorescence and the weak Raman signals were acquired and spectroscopically analyzed between 800 and 1000 nm. The increase of fluorescence intensity between 3.5 and 11.5 days of incubation was found to be in agreement with the erythropoietic stages, thus enabling to identify hemoglobin as fluorescence source. Sex-related differences in the fluorescence spectrum were found at day 3.5, and principal component (PC) analysis showed that the blood of males was characterized by a specific fluorescence band located at ∼910 nm. Supervised classification of the PC scores enabled the determination of the sex of 380 eggs at day 3.5 of incubation with a correct rate up to 93% by combining the information derived from both fluorescence and Raman scattering. Graphical abstract The fluorescence of blood obtained in ovo by illumination of embryonic vessels with a IR laser displays spectral differences that can be employed for sexing of eggs in early stage of incubation, before onset of embryo sensitivity and without hindering its development into a healthy chick.
authors.affiliation: Faculty of Medicine, Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany. roberta.galli@tu-dresden.de.
authors.forename: Roberta
authors.initials: R
authors.lastname: Galli
authors.affiliation: Faculty of Medicine, Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
authors.forename: Grit
authors.initials: G
authors.lastname: Preusse
authors.affiliation: Faculty of Medicine, University Hospital Carl Gustav Carus, Neurosurgery, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
authors.forename: Ortrud
authors.initials: O
authors.lastname: Uckermann
authors.affiliation: Faculty of Veterinary Medicine, Clinic for Birds and Reptiles, University of Leipzig, An den Tierkliniken 17, 04103, Leipzig, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bartels
authors.affiliation: Faculty of Veterinary Medicine, Clinic for Birds and Reptiles, University of Leipzig, An den Tierkliniken 17, 04103, Leipzig, Germany.
authors.forename: Maria-Elisabeth
authors.initials: ME
authors.lastname: Krautwald-Junghanns
authors.affiliation: Faculty of Medicine, Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
authors.forename: Edmund
authors.initials: E
authors.lastname: Koch
authors.affiliation: Faculty of Medicine, Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany. gerald.steiner@tu-dresden.de.|Faculty of Physics, Vilnius University, Sauletekio av. 9 bl. 3, 10222, Vilnius, Lithuania. gerald.steiner@tu-dresden.de.
authors.forename: Gerald
authors.initials: G
authors.lastname: Steiner
mesh_terms: D000818:Animals; D002645:Chickens; D004531:Eggs; D005260:Female; D008297:Male; D012732:Sex Determination Analysis / Q000379:methods*; D013050:Spectrometry, Fluorescence / Q000379:methods*
keywords: Chicken embryo; Fluorescence; In ovo; Optical spectroscopy; Raman scattering; Sexing