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Incubation of duck eggs without removal of cuticle

The removal of the cuticle has always been a common practice when incubating duck eggs. However, this removal involves a higher risk of contamination, possibly resulting in a huge negative impact on hatchery results. Petersime’s Dynamic Weight Loss System™ offers an alternative for the incubation of duck eggs, making the removal of the cuticle redundant, thereby reducing the risk of contamination.

By Roger Banwell, Hatchery Development Manager

Removal of cuticle for better gas exchange

The cuticle offers a natural protective coating on the outer surface of the egg (see Figure 1). This coating creates a barrier that inhibits bacteria, fungal or other agents of contamination from entering the egg through the pores. The cuticle of duck eggs is thicker compared to the cuticle of chicken eggs, which makes the gas exchange between the embryo and the environment more difficult. Therefore the cuticle of duck eggs needs to be removed before or during incubation to allow sufficient gas exchange.

Figure 1: anatomy of an egg (Source: Horst, Frank. Anatomy of an egg, 2007)

Duck egg with partly removed cuticle for better gas exchange

Natural incubation process

In nature, the cuticle of duck eggs will gradually degrade during incubation due to the turning action of the parent bird and the nest activity. This degradation results in more exposed pores and consequently in an increasing rate of gas exchange throughout the natural incubation process. During the first 12 days, the embryo is very sensitive to contamination. In this phase, the weight loss is still limited because the cuticle is almost completely intact, which minimizes contamination. Afterwards, when the embryo is more resistant to contamination, the parent bird enhances weight loss by degrading the cuticle. The weight loss profile of the natural incubation process of a duck is shown in Figure 2.

Figure 2: Linear versus natural weight loss profile of duck eggs during incubation

Hatchery practices

The hatching industry typically removes the cuticle of duck eggs by washing the eggs with a chlorine solution before incubation or by spraying them with water during incubation. This practice results in a linear weight loss profile (see Figure 2). Because the cuticle is already removed before or during the first days of incubation, when the embryo is still very fragile, the risk of contamination is higher compared to the natural incubation process. Moreover the constant use of water inside the incubator causes a build-up of corrosion and calcium. Such bacterial breeding areas are difficult to clean and reduce the lifetime of hatchery equipment. 
 

Microscopic view (x200) of unwashed (left) and washed (right) egg

Dynamic Weight Loss System™

Due to the Dynamic Weight Loss System™ of Petersime, the natural weight loss profile can be mimicked without the removal of the cuticle. The partial pressure of O2, CO2 and water vapor can be regulated, generating a large gradient of these gasses between the outer and inner surface of the egg. Because of this large gradient, the transport of gas will still occur across the cuticle, which is not possible under former incubation conditions. Because the cuticle is still intact, the risk of contamination is minimized.

Figure 3 shows clearly that the weight loss profile of duck eggs using the Dynamic Weight Loss System™ (DWLS™) is similar to the profile of the natural incubation process in Figure 2. Knowing that an incubating bird provides the ideal conditions for an optimal hatch, Petersime hereby provides the optimal program and equipment that can mimic these conditions. 
 

Figure 3: Ventilation and weight loss profile during the incubation of duck eggs with (cuticle intact) and without (cuticle partly removed) Petersime’s Dynamic Weight Loss System™

Conclusion

Petersime’s Dynamic Weight Loss System™ enhances bio-security in different ways. The cuticle remains intact, which minimizes the risk of contamination. The additional contamination risk by washing the eggs or artificial humidification is excluded and the intake of potentially contaminated air is kept to a minimum. On top of this, the Dynamic Weight Loss System™ provides O2 and removes CO2 and water in correlation with the requirements of the developing embryo for optimal incubation conditions, which improves hatchability, chick quality and post-hatch performance.