Abstract

OKUR, N.  and  ERATALAR, S.A.. Effects of ventilation programme and eggshell thickness on hatchability rate and hatching time of broiler eggs. S. Afr. j. anim. sci. [online]. 2021, vol.51, n.2, pp.205-211. ISSN 2221-4062.  http://dx.doi.org/10.4314/sajas.v51i2.8.

The aim of the research was to determine whether enrichment of the atmosphere in an incubator with carbon dioxide (CO₂) and oxygen (O₂) and eggshell thickness (EST) affected embryonic death (ED), hatchability of fertile eggs (HFE) and hatching time (HT). A total of 320 Ross 308 eggs were used and the experiment was repeated twice. Eggshell thickness was classified as thin (<31 μηι), medium (31 - 32 μηι) and thick (>32 μπι). The incubators were operated with their internal atmosphere enriched with CO₂ (1.57% CO₂; 20.23% O₂) or O₂ (0.50% CO₂; 22.44% O₂). Embryonic death, HFE and HT data were monitored at three periods, namely early (<486 hours), middle (486 - 492 hours), and late (492 - 510 hours). Early ED, late ED and hatchability of fertile eggs were not affected by EST or by the incubator's internal atmosphere (P >0.05). Thus, O₂ supplementation to the incubator was deemed unnecessary at 822 m altitude. There was a highly significant interaction between EST and HT. Eggs with shells 31 to 32 μπι thick hatched at an appreciably greater rate between 486 and 492 hours of incubation (17%) than eggs with thicker (0.6%) or thinner (0.4%) shells in both the CO2 and O2 enriched atmospheres. The hatching rate was significantly higher in the eggs with an intermediate EST than in thick-shelled eggs. A greater proportion of eggs hatched at the late HT as opposed to earlier, regardless of EST.

Keywords : broiler; eggshell thickness; hatching time; incubator ventilation programme.

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