Effect of pre-incubation long-term storage and warming on hatch- ability of Japanese quail eggs (Coturnix coturnix japonica) Einfluss einer langen Lagerdauer und des Anwärmens von Wachteleiern (Coturnix coturnix japonica) vor der Brut auf den Bruterfolg

Optimizations of storage period and storage conditions of hatching eggs play an essential role in poultry husbandry for economical reasons. Pre-incubation storage period of eggs is likely to be longer than a week in laying hen producers as well as in poultry breeding companies. It has been recommended that hatching eggs should not be stored more than 7 days since the eggs may lose their hatchability due to spoilage (SOLEY, 1994). Hatchability decreases under even optimum conditions of eggs stored more than one week (DEMIRCIOGLU, 1994, ELIBOL, 1997, IPEK et al., 1999). Commercial hatching establishments, especially the ones with high capacity, may have to store hatching eggs for a long period of time before incubation to decrease the cost such as labour and energy, to synchronize the time of hatching, and sometimes to limit the production depending on the market demand. Likewise, breeding establishments producing pedigreed parents may sometimes need to store hatching eggs longer before the incubation to produce a number of full-siblings. Evaporation of water in eggs depends on storage temperature and relative humidity. Increased loss of water content of the hatching eggs during storage may result in underdevelopment or death of embryos at different stages of the incubation. A quail egg may lose approximately 2% of its initial weight after 7 days of storage at room temperature (SOLEY, 1994). It has been reported that hatchability of quail eggs may decrease by 2-3% after 4 days of storage even under optimum conditions (IMAI et al., 1986, SUKSUPATH and TANPIPAT 1991). The “Physiological zero” for poultry eggs has been reported between 19°C and 27°C (PROUDFOOT and HULAN, 1976; DECUYPERE and MICHELS, 1992). Basal research indicates that during storage there are no discernible embryonic development and the embryo remaining in a state of embryonic diapauses when the eggs are held at temperatures below physiological zero. However, embryonic development still occurs during storage, although at a minimum rate, and therefore this fact may contribute to the decline in viability as the storage period increases (MEIJERHOF, 1992, MAYES et. al., 1984).