Embryonic development of quail eggs (Coturnix coturnix japonica) in a homemade incubator

Knowledge of the embryonic development of species such as quail is important for our understanding of its production and reproduction. Quail provides a practical solution to the animal protein shortage problem in developing countries and is an excellent alternative to chicken (Shanaway, 1994). This study evaluated quail embryonic viability by comparing the main morphological changes that occur over the development in a homemade incubator with previous data; the incubator was built using easily accessible and low-cost materials, which allows small producers and communities to develop quail farms as an activity to increase income or even produce a source of animal protein for the community in the Brazilian Amazon region. The homemade incubator measured 40 cm × 42 cm × 32 cm and was constructed with wooden boards, a digital thermostat, and an incandescent lamp. A total of 24 fertile eggs were incubated at a temperature of 37.5 °C and 60% relative humidity; age “0” was set at the start of incubation. Two eggs were opened on each day of development, starting from day 5 to day 16 of incubation. After gently opening the eggs, the embryos were removed, separated from the placenta and amniotic fluid, washed with running water, and weighed on a digital scale (SHIMADZU AUY 220 brand and UNI BLOC model). Crown-rump length and other measurements were performed with a digital caliper and the morphological structures were observed using a stereomicroscope (NOVA brand and NOVA ZTX-E model). All eggs opened contained live embryos, indicating that the homemade incubator temperature, relative humidity, and manual turning were adequate to maintain the quail's viability. The morphometric data of the embryos at different developmental time points were similar to those described in the literature. Embryos weighed 0.0069 g at day 5 and 4.7863 g at day 16, and the crown-rump length (CRL) means were 0.368 cm and 3.657 cm, respectively. Weight and CRL increased by 0.434 g and 2.593 cm per day of incubation, respectively. In conclusion, after 16 days of incubation in a homemade incubator, the embryos presented all phases of the development cycle, with appropriate development of weight and height based on the days of incubation without anomaly or external interference. These findings demonstrate that the homemade incubator does not alter the embryonic development of quail embryos in the Brazilian Amazon region.