Table 2 Overview of non-optical in ovo sexing techniques
From: Trends in in ovo sexing technologies: insights and interpretation from papers and patents
Category | Target | Incubation day/ Accuracy/ Throughput | Technology (patents)/ Research gaps (papers) | Advantages (+)/ Drawbacks (-) | References |
|---|---|---|---|---|---|
DNA analysis | gDNA (e.g., CHD, XhoI, SWIM, HINTW) from different samples (e.g., AF, blood, feathers, brain) | d 8 to 13/ 100%/ Slow (slower in case of need for DNA extraction), PCR can take more than 60 min | Technology > Research Lack of papers using AF Several possible female-specific sequences are not reported in the literature |  +  High accuracy Early in incubation (> d 2.5) - Lengthy processes and expensive Can be highly invasive if not using AF | Patents □ Griffiths [14], □ Clinton [15], ○ Dalton et al. [16], ○ Arie and Danielli [17], ◊ Molina and Espeut [18], ○ Weigel et al. [19] Papers Li et al. [20], Haunshi et al. [21], Clinton et al. [22], He et al. [23], Petitte and Kegelmever [24] |
Immunosensing | Sexual hormones (e.g., E2 or estrone-3-sulfate) in AF or blood | Minimum d 8/ Reported as 99% on d 9/ Relatively slow using ELISA/RIA, which can take up to 90 min | Technology ≅ Research Well defined in both papers and patents |  +  Applicable in AF - Limited to after d 8 of incubation Lower accuracies than DNA analysis Expensive and lengthy testing | Patents ◊ Tyczkowski et al. [25], ○ Butt and Tran [26], ○ Einspanier [27, 28], □ Phelps [29], ◊ Meter [30, 31] Papers Phelps et al. [12], Tanabe et al. [32], Weissmann et al. [33, 34], Müller et al. [35], Aslam et al. [36], Wang et al. [37] |
IMS and MS | Metabolites in AF | d 9 to 10/ 90% to higher than 95%/ Relatively fast | Technology > Research Only defined by 2 different groups of inventors in the patent literature No work has been published in the scientific literature |  +  Quick sampling and relatively fast analysis - No scientific literature on physiological background | Patents □ Daum and Atkinson [38], ○ Bruins and Stutterheim [39, 40], ◊ Stutterheim et al. [41,42,43] Papers - |
Genetic engineering | gDNA | d 0 to 2.5/ 100%/ High if using labels | Technology > Research Only one short communication in papers, mainly present in patents |  +  High accuracies at an early incubation stage - Not accepted in several countries (see text) Invasive injection of a labeled molecule (antibody/DNA sequence) | Patents ◊ Decuypere and Fey [44], ○ Offen [45], □ Beisswanger [46] Papers |
VOC analysis | VOCs released from the egg | d 0 or during incubation/ Accuracy not defined/ s to min | Technology > Research Patents use real-time analysis systems such as THz spectroscopy, SIFT- or PTR-MS Research papers use conventional SPME–GC–MS analysis and more research is required for generating robust sexing models |  +  Non-invasive Potential for early-stage application - Contamination risk of egg odor by environment or other eggs | Patents ◊ Rivers [49], ○ Gabbai [50], ○ Knepper et al. [51], ○ Shi et al. [52] Papers Webster et al. [53], Costanzo et al. [54], Xiang et al. [55] |
Other | 1) Electrical and magnetic polarity 2) Dynamic electromagnetic spectrum 3) Sex-specific compounds close to the eggshell 4) Bioimpedance measurements | d 0 or d 9/ Accuracies unknown/ No throughputs defined | Technology > Research Only defined in different patents and no scientific literature |  +  Before incubation Non-invasive - Little scientific evidence | Patents □ Young [56], □ Williams [57, 58], □ Chadfield [59], □ Pacala et al. [60], ○ Visser [61], ◊ Rastoutsau et al. [62] Papers Ching et al. [63] |