Research Note: Nondestructive detection of super grade chick embryos or hatchlings using near-infrared spectroscopy.

Some unresolved questions in poultry science were addressed: what determines the yield of chick embryos or hatchlings; what kind of influence does egg yolk content have on embryonic development; and how to detect eggs producing super grade chicks? Since the yolk acts as a vital energy and nutrient reservoir for embryos, we hypothesized that a higher yolk content of similar sizes eggs would play an important role in embryo or chick viability during incubation, as well as at hatch. As experimental sample, we used ROSS 308 (broiler line) and a nondestructive spectroscopic absorbance method. The influence of high yolk content to embryonic heartbeat and chick yield (i.e., chick weight/egg weight) were then investigated. Embryonic heartbeat signal was measured indirectly using a prototype near-infrared sensor during incubation period. A positive influence was found in both cases. Similar size eggs with higher yolk content were found to significantly (P-value < 0.05) promote higher chick yield at hatch. This methodology may have the potential to be used to precision poultry production system, ornithology, developmental, or evolutionary biology in the near future.

Chick Embryo Growth Modeling Using Near-Infrared Sensor and Non-Linear Least Square Fitting of Egg Opacity Values.

Non-destructive monitoring of chick embryonic growth can provide vital management insights for poultry farmers and other stakeholders. Although non-destructive studies on fertility, hatching time and gender have been conducted recently, there has been no available method for embryonic growth observation, especially during the second half of incubation. Therefore, this work investigated the feasibility of using near-infrared (NIR) sensor-based egg opacity values-the amount of light lost when passing through the egg-for indirectly observing embryo growth during incubation. ROSS 308 eggs were selected based on size, mass and shell color for this experiment. To estimate the embryo size precisely, we fit various mathematical growth functions during incubation, based on the opacity value of incubated eggs. Although all the growth models tested performed similarly in fitting the data, the exponential and power functions had better performances in terms of co-efficient of determination (0.991 and 0.994 respectively) and RMSE to explain embryo growth during incubation. From these results, we conclude that the modeling paradigm adopted provides a simple tool to non-invasively investigate embryo growth. These models could be applied to resolving developmental biology, embryonic pathology, industrial and animal welfare issues in the near future.

A Nondestructive Eggshell Thickness Measurement Technique Using Terahertz Waves.

Eggshells play a number of important roles in the avian and reptile kingdom: protection of internal contents and as a major source of minerals for developing embryos. However, when researching these respective roles, eggshell thickness measurement remains a bottleneck due to the lack of a non-destructive measurement techniques. As a result, many avian and reptile research protocols omit consideration of eggshell thickness bias on egg or embryo growth and development. Here, we validate a non-destructive method to estimate eggshell thickness based on terahertz (THz) reflectance spectroscopy using chicken white coloured eggs. Since terahertz waves are reflected from outer air-eggshell interface, as well as the inner eggshell-membrane boundary, the resulting interference signals depend on eggshell thickness. Thus, it is possible to estimate shell thickness from the oscillation distance in frequency-domain. A linear regression-based prediction model for non-destructive eggshell thickness measurement was developed, which had a coefficient of determination (R2) of 0.93, RMSEP of 0.009, RPD of 3.45 and RER 13.67. This model can estimate eggshell thickness to a resolution of less than 10 µm. This method has the potential to expand the protocols in the field of avian and reptile research, as well as be applied to industrial grading of eggs.