6 Restoring the hatchability
Realising the potential of this treatment has been the challenge for the industry and equipment manufacturers. There have been numerous attempts both in the commercial and academic environments to achieve consistent gains with this principle but both have reported variable results. It is clear that inaccurate treatment frequency will at best give limited gains or at worst take the embryo beyond the ‘point of no return’ and result in destructive consequences.
Equally critical are the treatment parameters in terms of absolute temperature and transition durations. An excessive treatment, for example when the eggs are heated up too fast or up to a too high temperature for too long, will bring the embryos beyond the point of no return. This means that the embryos have advanced to beyond stage XIII and that the embryonic development cannot be stopped anymore. Putting these eggs back into the cold storage room will negatively affect their viability. The research work carried out by Aviagen has made major strides in identifying the optimum temperature, timings and operating temperature bandwidth for heat treatment during storage. It has become clear that, in order to achieve consistent gains in hatchability and post-hatch performance, the key process parameters in the incubator need to be controlled very accurately. It is crucial to achieve the correct egg shell temperature. The eggs need to be heated up to an egg shell temperature of more than 32°C; yet keeping the eggs above 32°C for too long will negatively affect hatchability. Another important factor in the process is the warming-up and cooling-down phases.
Therefore, Petersime has developed an incubator dedicated to heat treatment during storage. Equipped with the patented OvoScan technology, it precisely monitors and controls the egg shell temperature during the entire heat treatment process. The machine guarantees an accurate, controlled and uniform warm-up and cooldown phase as this is vital for the consistency of the results. In practice, applying heat treatment during storage on a regular basis can become very time consuming for the hatchery staff. With the dedicated Petersime incubator, it is possible to automate several of the steps in this process. The desired temperature trajectory can be fully programmed in advance by the hatchery manager, and the OvoScan will control the process throughout the cycle.
Petersime has run several large scale trials, using a dedicated incubator with a capacity of 57,600 eggs. In a first phase, trials were conducted with grandparent flock eggs with a successful outcome in terms of egg shell temperature control, temperature uniformity throughout the incubator, consistency of the warm-up and cool down phases and hatchability restoration. During the incubation process, the internal environment throughout the entire treatment cycle was controlled based on egg shell temperatures. In a second phase, trials were conducted in a commercial broiler operation. During these trials, hatchability, chick quality and post-hatch performance data have been acquired and analysed. Initial investigatory heat treatment tests were done with variable results, but ultimately an optimum parameter configuration was derived. Based on the identified parameters, a series of trials were started where eggs from the same source were given different treatments: half of the eggs were incubated after three days of storage, the other half after 12 days of storage with heat treatment. A total of four trials were completed with no loss in hatchability (±0.2%) and post-hatch data showed no significant difference (Fig. 2). A further series of identical trials were undertaken targeting 15 days of storage with similar consequences (Fig. 3). This confirms the huge potential of the heat treatment methodology. Further optimisation trials are ongoing, investigating both extending the storage duration and the effect of earlier treatments on post-hatch performance.