VisEgg: a robust phenotyping tool to assess rainbow trout egg features and viability


Assessing female fish reproductive success requires a thorough evaluation of egg characteristics, including egg number, size, and variability as well as egg developmental potential through the monitoring of embryo survival after fertilization. While embryonic success relies, at least in part, on paternal contribution, some parameters are strictly related to egg characteristics, one of the main ones being the viability of the egg when released into the water at spawning. It is however not necessarily possible, at least in salmonid fish that lay nontransparent eggs, to separate the different causes of egg/embryo failure. In this context, our aim was (i) to develop a simple and rapid system to capture images of rainbow trout eggs combined with computerized processing of these images to perform a fully automatic individual characterization of egg features including number and size (ii) to estimate unfertilized egg viability through the monitoring of the percentage of eggs that will not survive to water hydration. To evaluate the VisEgg system, unfertilized eggs (approximatively 400 eggs per batch) originating from 105 different females were hydrated in water. After 24 h, a picture of the eggs was obtained using a dedicated shooting system consisting of a light source and a digital single-lens reflex (SLR) camera. An image processing algorithm was developed to allow the automatic detection and separation of the eggs and to perform automatic measurements of egg number and individual egg size. The presence of white egg was used as an indirect measure of egg integrity, the “whitening” being the result of water entry into the egg through the vitelline membrane. These white eggs were therefore considered nonviable, as a result of their lack of physical integrity. Fertilization assays were performed in parallel using a subsample of the same egg batch. Embryonic development was monitored and hatching rate was calculated. A significant correlation between white egg percentage after hydration and hatching rate was observed (Spearman coefficient = −0.557, p < 0.001), in consistency with the fact that nonviable egg will not allow successful embryonic development. In contrast, the percentage of eggs that do not successfully hatch includes egg/embryo failures of different nature including reduced egg viability. Using the VisEgg, we were able to quantify the lack of viability of the eggs separately from the different other events that may occur during fertilization and incubation. the VisEgg is a convenient and reliable tool to obtain individual measures on trout eggs. It can be used to assess not only egg size and egg number but also unfertilized egg viability before fertilization.

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  1. Alderdice DF (1988) Osmotic and ionic regulation in teleost eggs and larvae. Fish Physiol 11:163–251.

    Article  Google Scholar 

  2. Blaxter JHS (1969) Development: eggs and larvae. Fish Physiol 3:177–252.

    Article  Google Scholar 

  3. Bobe J (2015) Egg quality in fish: present and future challenges. Anim Front 66–72:66–72.

    Article  Google Scholar 

  4. Bobe J, Labbé C (2010) Egg and sperm quality in fish. Gen Comp Endocrinol 165:535–548.

    CAS  Article  PubMed  Google Scholar 

  5. Bromage N, Jones J, Randall C, Thrush M, Davies B, Springate J, Duston J, Barker G (1992) Broodstock management, fecundity, egg quality and the timing of egg production in the rainbow trout (Oncorhynchus mykiss). Aquaculture 100:141–166.

    Article  Google Scholar 

  6. Brooks S, Tyler CR, Sumpter JP (1997) Egg quality in fish: what makes a good egg? Rev Fish Biol Fish 7:387–416

    Article  Google Scholar 

  7. Campbell PM, Pottinger TG, Sumpter JP (1992) Stress reduces the quality of gametes produced by rainbow trout. Biol Reprod 47:1140–1150.

    CAS  Article  PubMed  Google Scholar 

  8. Engelmann F, Friedel T, Ladduwahetty M (1976) The native vitellogenin of the cockroach Leucophaea maderae. Insect Biochem 6:211–220.

    CAS  Article  Google Scholar 

  9. Fremont L, Riazi A (1988) Biochemical analysis of vitellogenin from rainbow trout (Salmo gairdneri): fatty acid composition of phospholipids. Reprod Nutr Dev 28:939–952.

    CAS  Article  PubMed  Google Scholar 

  10. Gray BYJ (1932) The osmotic properties of the eggs of the trout (Salmo fario). J Exp Biol 9:277–299

    CAS  Google Scholar 

  11. Heath DD, Heath JW, Bryden CA, Johnson RM, Fox CW (2003) Rapid evolution of egg size in captive salmon. Science. 299:1738–1740.

    CAS  Article  PubMed  Google Scholar 

  12. Jastrebski CJ, Morbey YE (2009) Egg size variation in lake trout: phenotype–habitat correlations show an effect of rearing environment. Trans Am Fish Soc 138:1342–1351.

    Article  Google Scholar 

  13. Kobayashy W (1985) Electron microscopic observation of the breakdown of cortical vesicles in the chum salmon egg. J Fac Sci Hokkaido Univ 24:87–102

    Google Scholar 

  14. Kuchnow KP, Scott JR (1977) Ultrastructure of the chorion and its micropyle apparatus in the mature Fundulus heteroclitus (Walbaum) ovum. J Fish Biol 10:197–201.

    Article  Google Scholar 

  15. Lahnsteiner F, Weismann T, Patzner RA (1999) Physiological and biochemical parameters for egg quality determination in lake trout, Salmo trutta lacustris. Fish Physiol Biochem 20:375–388.

    CAS  Article  Google Scholar 

  16. Lubzens E, Young G, Bobe J, Cerdà J (2010) Oogenesis in teleosts: how fish eggs are formed. Gen Comp Endocrinol 165:367–389.

    CAS  Article  PubMed  Google Scholar 

  17. Migaud H, Bell G, Cabrita E, Mcandrew B, Davie A, Bobe J, Herráez MP, Carrillo M (2013) Gamete quality and broodstock management in temperate fish. Rev Aquac 5(Suppl. 1):S194–S223.

    Article  Google Scholar 

  18. Springate JRC, Bromage NR (1985) Effects of egg size on early growth and survival in rainbow trout (Salmo gairdneri Richardson). Aquaculture 47:163–172

    Article  Google Scholar 

  19. Van Heerden E, Van Vuren JHJ, Steyn GJ (1996) Effect of excreta, blood and vitellus contamination on fertilisation success of Oncorhynchus mykiss. Aquaculture 141:173–182.

    Article  Google Scholar 

  20. Yamamoto T (1962) Physiology of fertilization in fish eggs. Int Rev Cytol 12:361–405.

    Article  Google Scholar 

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We thank Francois Guivarc’h for animal care and the INRAE PEIMA and LPGP staff for their help during the reproduction season.


This study was supported by the European Maritime and Fisheries Fund Grant No. PFEA470016FA1000002.

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Correspondence to Julien Bobe.

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Experimentations were conducted in the INRAE PEIMA experimental facility (Sizun, France—Agreement number B29-277-02). All fish were reared and handled in strict accordance with French and European policies and guidelines of the INRAE PEIMA Institutional Animal Care and Use Ethical Committee, which specifically approved this study. Fish were monitored daily during the experiment. If any clinical symptoms (i.e., morphological abnormality, restlessness, or uncoordinated movements) were observed, fish were sedated by immersion in MS-222 solution at a concentration of 50 mg L−1 and then euthanized by immersion in a MS-222 solution at a concentration of 400 mg L−1 (anesthetic overdose) in 3 min.

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Supplementary Table 1

Table presenting raw data for all 105 spawns used for the construction of Figs. 4 and 5 (XLSX 32 kb)

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Cardona, E., Bugeon, J., Segret, E. et al. VisEgg: a robust phenotyping tool to assess rainbow trout egg features and viability. Fish Physiol Biochem (2020).

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  • VisEgg
  • Image analysis
  • Phenotyping method
  • Rainbow trout
  • Egg viability