NON-LINEAR EGG WEIGHT LOSS IN LEGHORN BREEDER EGGS INCUBATED AT HIGH ALTITUDE IMPROVES HATCHLING PHYSICAL QUALITY TRAITS

Resumen

Artificial incubation (AI) is essential for producing healthy, high-quality one-day-old chicks; however, continuous optimization of incubation conditions, particularly at high altitudes, remains necessary. Among these conditions, relative humidity (RH) is a crucial factor. Egg weight loss (EWL) during incubation plays a key role in embryonic development and the hatching process. This study evaluated the effects of non-linear and standard EWL patterns during incubation at high altitude. Hatching eggs from 36- and 41-week-old Leghorn breeders (n=672) were evaluated. An airtight experimental incubation system was designed to allow a gradual increase of CO₂ concentration and RH, generating differential conditions between treatments during the early stage of incubation (days 0-10). Results revealed that the non-linear EWL protocol applied during AI at high altitude did not cause any significant increase in embryonic mortality. Hatchability of fertile eggs (HFE) was slightly higher (>3-5%) than that observed under standard EWL incubation conditions. The hatchling physical quality index under the non-linear EWL approach, from both breeder hen age groups, was significantly increased (>9%) compared with the respective standard EWL groups. Therefore, non-linear EWL management during incubation at high altitude has the potential to improve HFE, hatchling physical quality score, and thus post-hatch performance in the field. However, before the non-linear EWL method can be adopted as a standard protocol in AI at high altitude, further adjustments should be investigated, as these may vary according to each hatchery and individual egg batch.