ABSTRACT
The breeding of male layer chickens is currently considered to be highly uneconomical. In Germany alone, 40 to 50 million newly hatched male chickens were killed annually immediately after hatching. Therefore, it is necessary to find a method for sexing chickens early in the embryonic development, preferably before incubation. The genotypic sex of an egg can be determined using information found in the germinal disc, so knowledge of the exact position of the germinal disc is essential for further sexing, or for other actions such as the in ovo injection of agents. Previous studies have shown that the germinal disc is located somewhere on top of the yolk. However, no studies have yet been performed that investigate the influence of time spent in horizontal storage on the position of the germinal disc. Magnetic resonance imaging was chosen to determine this influence on the position of the germinal disc. It was found that eggs placed horizontally for long periods of time before scanning had significant changes in the positions of their germinal discs compared with those of eggs scanned minutes after positioning. The position of the germinal disc in eggs, minutes after horizontal positioning, deviated 14.7 ± 0.6 mm from the maximum vertical plane of the egg (zero position) in the z-direction; eggs scanned after 96 h of horizontal positioning showed a deviation of only 4.9 ± 1.6 mm. The x-axis also exhibited changes in the position of the germinal disc over time. Immediately after horizontal positioning, the eggs showed a deviation of 0.4 ± 0.4 mm in the x-direction, whereas the deviation after 96 h was 2.9 ± 0.5 mm. These results show that horizontal positioning of the egg hours before the measurement is necessary.
Subject(s)
Blastodisc/anatomy & histology , Chick Embryo/anatomy & histology , Animals , Blastodisc/chemistry , Breeding , Female , Magnetic Resonance Imaging , Male , Sex Determination Analysis/methods , Sex Determination Analysis/veterinary , Time FactorsABSTRACT
Fourier transform infrared (FT-IR) spectroscopy was used to probe the molecular composition of germinal cells and to identify the gender of turkey poults. Germinal cells obtained from a feather pulp were characterized by FT-IR micro spectroscopy. The sample set consisted of growing contour feathers from 23 male and 23 female turkey poults. Significant spectral variations were observed in the range between 1,000 and 1,250 cm(-1). The spectra of male turkey poults exhibit a significantly higher content of RNA than those of female turkeys. Spectral classification was performed by a non-supervised method based on the principal component analysis. An evaluation of the first and third PCs led to a classification of female and male poults with an accuracy of more than 95%.
