The study of time-varying speckle phenomena observed in light-fields scattered from living objects is reviewed. The laser speckles produced from living objects may be called ‘bio-speckles’ and fluctuate temporally due to various physiological movements such as blood flow. The time-varying properties of the bio-speckles are experimentally investigated from the analyses of the power spectrum and the autocorrelation function. Based on the knowledge of dynamic bio-speckles, some methods are introduced for evaluating blood flow in the skin surface, internal organs, and ocular fundus. The experimental results show that the degree of blood flow is reflected sensitively by the time-varying properties of the bio-speckles and this can be utilized for monitoring the blood flow.

Bio-speckle phenomena and their application to the evaluation of blood flow

We have measured noninvasively the embryonic heart rate (HR) of the Japanese quail (Coturnix coturnix japonica), the chicken (Gallus domesticus), the duck (Anas platyrhynchos), the turkey (Meleagris gallopavo), the peafowl (Pavo cristatus), and the Chinese goose (Anser cygnoides) during approximately the last half of the incubation period. The average daily HR was determined over 30 s, every 5 min for 30 min. The HR was variable, particularly toward the end of incubation and during pipping. The time trend of changes in daily HR was similar in quail, chicken, and turkey eggs: a temporal increase occurred at 60%-70% of the incubation period, with a subsequent decrease toward the end of prepipping development, and then an increase with the breathing of air by the lungs. The duck and goose embryos decreased the HR during the last stages of prepipping development. Although the changes in internal pipping HR of the duck were various, the HR of the goose was predominantly increasing during pipping. A gradual inc...

Embryonic Heart Rate during Development of Domesticated Birds

Monitoring the life status of a developing embryo is very useful, especially during last days of incubation when hatching could potentially be assisted if deemed necessary. A commercially available digital egg monitor (Buddy, Vetronic Services, Devon, UK) uses noninvasive methodology to monitor the heart rate of an embryo by measuring the amount of infrared light absorbed by embryonic blood. Thirty specific pathogen-free (SPF) chicken eggs (29 fertile) were incubated at 37.8 ± 0.1°C and the heart rate of each embryo was measured. Heart rates were first detectable in 13 eggs at day 6 of incubation. At day 7, an average heart rate of 170 ± 20 beats/min was detected in all 29 fertile eggs, which is comparable to reported values. Ten additional SPF chicken eggs were evaluated at day 13 of incubation to test the effects of ambient temperature changes on embryonic heart rate. Embryonic heart rates dropped from 262 to 106 beats/min in eggs kept at room temperature (25°C) for 90 minutes and to <60 beats/...

https://bioone.org/journals/journal-of-avian-medicine-and-surgery/volume-20/issue-3/2005-017R.1/Noninvasive-Heart-Rate-Measurement-Using-a-Digital-Egg-Monitor-in/10.1647/2005-017R.1.pdf

Noninvasive Heart Rate Measurement Using a Digital Egg Monitor in Chicken and Turkey Embryos

Ballistocardiography or impedance cardiography was used to measure on a daily basis the heart rate ($f_{H}$) of embryos of altricial pigeons (Columba domestica) and bank swallows (Riparia riparia). The patterns of $f_{H}$ changes during development were investigated. Embryonic $f_{H}$ of domestic and homing pigeons increases slowly during the middle stages of development and then increases sharply toward the end of incubation. Fantail pigeons show a diferent pattern of embryonic $f_{H}$ change; that is, $f_{H}$ remains constant until 1-2 d prior to external pipping and increases thereafter. Heart rate of the bank swallow increases continually throughout the last half of the incubation period. The developmental patterns of $f_{H}$ changes in pigeons and swallows generally are diferent from those of most precocial birds, in which embryonic $f_{H}$ decreases during the last stages of prepipping development.

Embryonic Heart Rate in Altricial Birds, the Pigeon (Columba domestica) and the Bank Swallow (Riparia riparia)

Our immediate goal was to study heart rate variability (HRV) in chicken embryos in the egg. Instantaneous heart rate data were needed for this purpose, and accordingly an ECG recording method in the egg was developed. The aim of this work was to test the hypothesis that autonomic nervous cardiac modulation, as shown from HRV parameters, is present at the end of development and that it reaches a constant value during the last days of incubation. Embryonic chicken heart rate was obtained at the final incubation period (days 19 and 20) from ECG recordings. Tachograms were computed and time- and frequency-domain indices of HRV were determined. No significant differences were found between HRV indices from day 19 and day 20. The power spectra extended in two frequency bands with centre frequency around 0.6-0.7 Hz (low frequency (LF) component), and another around 1.2-1.5 Hz (high frequency (HF) component); the latter was shown to reflect respiratory sinus arrhythmia. A relation between mean RR interval and some HRV parameters (rMSSD, pNN5 and HF power) was shown. HRV results obtained from embryonic chickens, showed the presence of modulation of cardiovascular function by the autonomic nervous system. The results suggested that sympathetic and parasympathetic activities have already reached a constant level at day 19 of incubation. High frequency oscillations (0.78-2.5 Hz) were detected and are considered to reflect respiratory sinus arrhythmia.

Heart rate and heart rate variability in chicken embryos at the end of incubation.

A new, noncontact system for measuring the heart rate of avian embryos in the egg has been developed using a laser speckle phenomenon. The system was based upon detection of egg movements attributable to cardiac contractions of the embryo by measuring the intensity fluctuation of speckle produced in the proximity of the egg under laser light illumination (i.e. noncontact measurement). The applicability of the noncontact system to determine the heart rate of developing chick embryos was examined simultaneously with a contact system employing an audio cartridge. Both systems were found to be feasible in determining the heart rate of embryos during the late prenatal and paranatal stages. With the aid of adeques signal processing, the measurement of cardiogenic movements of the egg can be used to count the heart rate during the middle stages of incubation.

T. Asakura

Papers

Noncontact measurements of avian embryo heart rate by means of the laser speckle: comparison with contact measurements