The conditions in a modern incubator can be controlled accurately, but the optimum conditions for each egg may not be the same and may vary throughout the incubation process. So how do you ensure that all chicks get the best possible start? Ampai Nangsuay and Conny Maatjens decided to address this question as part of their doctoral research. To do so they looked at the differences in eggs from different origins and the effects of temperature at the end of incubation, with some surprising results.
Hatching eggs come from various farms and breeders, and can therefore have different characteristics. For example, breeding farms select for various traits, the parents may have different ages and eggs can vary in size. These eggs therefore differ in terms of composition (fat, protein, and carbohydrates) and shell quality. The big question is whether these differences also affect the development of the embryo in the egg. Ampai Nangsuay, PhD researcher at the Adaptation Physiology Group of Wageningen University, investigated whether egg origin affects egg nutrients, O2 availability, and nutrient metabolism. This was indeed the case, which also has consequences for the nutrient conversion and development of the embryo. For optimum chick quality, this means that the incubation conditions should be adapted to the origin of the egg (breed, breeder age, egg weight).
Lower egg shell temperature yields better chick quality
The egg shell temperature (EST) is used to measure the temperature of the embryo in the egg. During the final week of incubation, embryonic growth and embryonic heat production increase. In practice, insufficient heat removal in the incubator increases the EST. If the EST becomes too high (>38.9°C), this probably leads to an imbalance; the increased metabolism causes reduced oxygen availability to the embryo, which has adverse effects on embryo development and ultimately on chick quality. Conny Maatjens, PhD researcher with the Adaptation Physiology Group of Wageningen University, studied the effects of reduced EST in the final week of incubation compared to the currently accepted optimum EST (37.8°C). The study came to the surprising conclusion that an EST of 35.6°C and 36.7°C results in an improvement in embryo development, organ growth, and growth performance in the first week after hatching. Further research should indicate whether these effects also lead to improvements in later life.
On the occasion of the PhD defence of Ampai Nangsuay (June 24) and Conny Maatjens (July 8), the seminar ‘The transition from eggs to hatchlings’ will be held on July 7 in Wageningen. The seminar is free, but registration by email is obligatory: firstname.lastname@example.org.