Incubação de ovos de codornas japonsesas em diferentes temperaturas: eclodibilidade, tempo de nascimento, peso ao nascer e mortalidade embrionária

Abstract

Temperature is the most important factor affecting embryonic development, hatchability and post hatch performance. Optimum incubation temperature is normally defined as that required to achieve maximum hatchability. This work was carried out to verify the effects of different incubation temperatures on hatchability, hatch weight, hatch time and embryonic mortality of Japanese quail eggs. A total of 800 eggs were divided in eight experimental groups that were incubated at different temperatures (34, 35, 36, 37, 38, 39, 40 and 41ºC). The other incubation conditions were identical for all groups, 60±5% of relative humidity and egg turning every two hours until transference to the hatchers at 15 days of incubation. The results showed that fertile hatchability was higher for eggs incubated at 37 and 38ºC, 76.6 and 80.7%, respectively. Eggs incubated at 34ºC did not hatch and the ones incubated at 35 and 41ºC showed very poor hatchability. The other temperatures had hatch rates from 50.3 to 57.7%. There were higher hatch weights in eggs incubated at high temperatures (38-41°C) compared to the ones incubated at the lower ones (35-37°C). There was an enormous difference in the hatching time according to the incubation temperature. The difference of time between the groups of eggs that hatched earlier (40°C) compared to the ones the hatcher later (35°C) was 156.3 hours or 6.5 days. Embryos seemed to be resistant to at high temperatures until 40°C at the early period of incubation, however the same was not observed at the later stages of incubation when high temperatures (39-41°C) increased embryonic mortality.