The sensor to estimate the sound pressure level in eggs

Effect of prenatal different auditory environment on learning ability and fearfulness in chicks

“…However, those of group HM and group HN were significantly difference than groups C, LN, and LM, which may be due to the acoustic insulation effect of eggshells on sound. Intact eggshells presented an insulation value of 17.14% at 70 dB that measured at the egg chamber with a special microphone [ 9 ]. This results in sound intensity after passing through the eggshell would not be enough to elicit a response from the embryo at 65 to 75 dB.…”

“…In artificial incubation, there are many technologies, such as ventilation, egg flipping, humidity and refrigeration systems used to ensure optimal conditions for the development of poultry embryos. During this process, noise caused by the engine and fan was inevitable, which results in a sound intensity approach up to 95 dB [ 9 ]. During the incubation period, 110 dB noise exposure can affect the development of the poultry brain, reduce brain volume and weight [ 10 ], increase thyroxine, and impair learning and memory ability [ 11 ].…”

Multilevel sensor for monitoring external and internal environment of eggs

“…After development, the device was calibrated, following the methodology adapted from Cavaliere et al, 2018 ; Donofre et al, (2018) ; Koestoer et al (2019) . In this way, the values of air temperature, relative humidity, internal temperature, surface temperature, sound pressure level and luminosity - all collected by the multilevel sensor - were calibrated by comparing them with readings obtained by commercial equipment.…”

“…For sound pressure level, electrical signals from the multilevel sensor output needed to be converted to dB, after which comparison could be made with the commercial decibel meter. In this case, the analytical procedure followed the protocol carried out by Donofre et al (2018) and Feitosa et al (2014) , and the descriptive model was adjusted using polynomial equations. From each of the models, the coefficient of determination (R²) and its characteristic equation were extracted.…”

“…These stimuli can be natural sounds, the vocalization of the species, music and constant noise, the latter being the case in commercial incubators ( Donofre et al, 2020 ). However, a scientific challenge lies in the lack of sensors to measure environmental variables inside eggs, which is crucial to understand the thermal, acoustic and light insulation provided by the shell and embryonic annexes ( Donofre et al, 2018 ). This is mainly due to the fact that there are no commercially available sensors which measure environmental variables in very small spaces, such as the inside of an egg.…”