Table 3 Overview of 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 |
|---|---|---|---|---|---|
Raman & fluorescence spectroscopy | Blood, eggshell, germinal disk, or other embryonic structures | d 3.5 to 5 96% accuracy on blood/ d 6 92.3% on embryo and blood/ Low to high throughput depending on the invasiveness | Technology ≅ Research The applicability on blood vessels is well reported in academic literature and is protected by patents Technology > Research A scientific gap exists in the analysis of the eggshell, germinal disk, or other embryonic structures since these are only reported in patent literature |  +  Early applicable in incubation No liquid or tissue sampling required - Intensive sampling procedure and relatively invasive process | Patents □ Baron et al. [ 77], ○ Steiner et al. [78], ○ Galli et al. [79], ◊ Schortgen [65], ○ Opitz et al. [80], ○ Popp et al. [81], ○ Schart [82], ◊ Herzog and Hurlin [83], ○ Steiner et al. [84], ○ Hurlin et al. [85] Papers Galli et al. [86,87,88], Preusse et al. [89], Gokdag et al. [90] |
IR & THz spectroscopy | Germinal disk | d 0/ Accuracy not defined/ Average throughput | Technology ≅ Research From the same group of authors, both patents and papers are reported for the IR approach Technology > Research Only a patent is reported for the non-invasive THz approach |  +  Applicable in an early stage - IR approach infringes hatchability | Patents ○ Steiner et al. [91], ○ May et al. [92], ◊ Xie et al. [93] Papers |
VIS–NIR spectroscopy | Heartbeat, blood hemoglobin, movement, feather color, yolk ratio, or growth (opacity) | d 0 to 14 depending on the technology/ High accuracies on color sexing 99%/ Blood sexing or other spectral features range from 80 to 90%/ High throughput | Technology ≅ Research Color sexing in the egg is commercially available and is described in both patent and paper literature Blood detection through the eggshell is described in paper and patent literature Technology > Research Other VIS–NIR spectroscopy on specific egg regions on specific d is only described in patents and lacks scientific background |  +  Has the potential for non-invasive implementation Equipment is affordable Early application potential - Lack of physiological background for sex-determining spectral features described in patents | Patents ○ McKay [96], ◊ Hurlin [ 97], ◊ Li et al. [98], ○ Preusse [99], ○ Fujitani [100, 101], □ Rams and Toellner [102], ○ Hebrank [ 103], ◊ Wang et al. [ 104], ◊ Adar [105], ◊ Colvin [106], ○ Ngadi et al. [107, 108], □ Zhao et al. [ 109, 110], ○ Rozenboim and Ben Dor [111], □ Pan et al. [112], ○ Green [113], ○ Zhu [114], ◊ Fischer and Meissner [115, 116], □ Yang et al. [117], ◊ Ngadi et al. [118] Papers Göhler et al. [119], Corion et al. [120], Khaliduzzaman et al. [121], Rahman et al. [122], Li et al. [123], Pan et al. [124] |
RF & NMR spectroscopy | Gonads, hormones, or metabolites | d 4 to 11 for hormones and metabolites/ accuracy not defined and relatively fast, d 18 gonads/ accuracy not defined and relatively slow | Technology > Research Almost only patent literature has been reported A single research paper reports the difficulty of detecting gonads |  +  Non-invasive Early incubation - No prediction accuracies are reported or known Gonad sexing relatively late | Patents ○ Bruins and Stutterheim [40], □ Reynells and Flegal [125], ○ Haase et al. [126], ○ Hergenroder et al. [127], ◊ Sewiolo and Ziroff [128], ○ Jaque Gonzalez et al. [129] Papers Davenel et al. [130] |
Morphometric studies | Eggshell morphology or blood morphology | d 0 for eggshell/ ~ 93 to 100%/ Relatively fast (using imaging technique), d 4 for blood/ 89.74%/ Relatively high throughput expected, yet equilibrium time needed in a horizontal position | Technology > Research Numerous patents are filed and a few papers One paper is using the formulas from a patent Not all papers did find sexual differences Using the shape index, there was a trend for female eggs to be more spherical, although the overlap was big with male eggs Blood vessel morphology sexing is described both in patent and paper literature, and it might require more research to verify the robustness |  +  Non-invasive Before or early incubation - Not enough scientific evidence that proves this technique works robustly nor an explanation of why there are sexual differences in the egg shape Blood vessel imaging requires a 2 min equilibration time in a horizontal position | Patents Taniguchi □ [131], □ [132], ○ [133], □ [134], ◊ [135], ◊ [136], □ [137], □ Lee et al. [138], □ Xiaohui et al. [139], □ Li et al. [140], □ Li [141], ○ Chen et al. [142], ◊ Zhu et al. [143] Papers Yilmaz-Dikmen et al. [144], Kayadan et al. [145], Rutkowska et al. [146], Zhu et al. [147] |