Evaluation of chicken embryo extract and egg yolk extract as alternatives to basic cell culture medium supplement

BMC Research Notes Mulugeta et al. BMC Research Notes (2024) 17:269 https://doi.org/10.1186/s13104-024-06899-1 Open Access R E S E A R C H N OT E Evaluation of chicken embryo extract and egg yolk extract as alternatives to basic cell culture medium supplement Fregenet Mulugeta3, Teferi Degefa2, Demise Mulugeta1, Anberber Alemu1, Jitu Beka4, Henok Ferede1, Dereje Nigussie Woldemichael1 and Fanos Tadesse Woldemariyam1* Abstract Background Fetal calf serum (FCS), an existing cell culture supplement, is effective but has several drawbacks, including being expensive, requiring a lengthy process of production, and requiring a hard currency. With this in mind, we planned to evaluate chick embryo extract and egg yolk extracts in cell culture as alternatives to fetal calf serum (FCS). Methods Specific pathogen-free eggs were purchased from the National Veterinary Institute, Bishoftu, Ethiopia, and incubated in a humidified incubator at 37 °C for 11 days. Egg yolk extract (EYE) and chick embryo extract (CEE) were collected after the egg was opened with caution not to destroy the yolk sack or the chick embryo itself. Chick fibroblasts and Vero cells were cultured in minimum essential medium (MEM) supplemented with egg yolk extract or chick embryo extract at ratios of 0:10, 1:9, 2.5:7.5, and 5:5% fetal calf serum. Results Fibroblast cell attachment was better in media supplemented with 5% CEE and 5% FCS. The confluency was also greater than 50% at this concentration. Vero cells cultured with 5% CEE and 5% FCS also exhibited very good cell attachment and a confluency of up to 70%. Viability and confluency were also observed at 5%:5% ratios of 50 and 70%, respectively. Conclusion This investigation evaluated these two extracts as cell culture supplements and revealed promising results as alternatives to fetal calf serum. The limitation of this study is that it only used two cell types and additional cell lines, and different ratios should be tested. With the above findings, further research using different cell lines, ratios and conditions is warranted. Keywords Cell culture, Chicken embryo extract, Egg yolk extract, Fetal calf serum, Cell attachment, Confluency, Cell viability *Correspondence: Fanos Tadesse Woldemariyam 1 Vaccine, Diagnostics and Medical Device Research and Development Directorate, Armauer Hansen Research Institute Jimma Road, ALERT Campus, P.O. Box: 1005, Addis Ababa, Ethiopia 2 National Veterinary Institute, P.O. Box: 19, Bishoftu, Ethiopia College of Veterinary Medicine and Agriculture, Addis Ababa University, P.O. Box:34, Bishoftu, Ethiopia 4 Institute of health, School of Public Health, Bule Hora Univesity, P.O. Box: 44, Bule Hora, Ethiopia 3 © The Author(s) 2024. 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To view a copy of this licence, visit http:// creativecommons.org/licenses/by-nc-nd/4.0/. Mulugeta et al. BMC Research Notes (2024) 17:269 Introduction Chick embryo extract (CEE) is derived from whole chick embryos and is known to contain essential proteins, growth factors, and hormones that are beneficial for cell culture [1]. CEE has been used to culture neural crest and neuroepithelial stem cells [1, 2]. In addition, CEE supplement has been shown as growth proliferation of human muscle stem cells [3]. Improvement of immune system performance was observed as a result of enhancement of lymphocyte proliferation supplemented by CEE [3]. Ongoing research is focused on understanding how a number of growth factors present in CEE synergistically contribute to enhancing cell growth in vitro [4]. The medium supplemented with the low and large molecular weight fraction of CEE promoted full differentiation and growth of cartilage and pigmented retina cells [5]. In chick embryos, a number of growth factors have been identified, including nerve growth factor (NGF), epidermal growth factor (EGF), and stem cell factor that are useful for cell proliferation (SCF) [6, 7]. These substances found in the CEE have been shown to enhance numerous physiological processes, including preserving neuronal survival and repairing tissue damage. Therefore, to generate a variety of stem cells, animal embryonic extract (chicken embryonic extract) is used as a growth factor cocktail [8]. Furthermore, it is believed that chicken embryo extract can provide functional and structural proteins to the medium used for in vitro cell development [9, 10]. The expansion and maturation of embryonic stem cells, neuronal cells, and neuroepithelial cells in culture have been promoted using these supplements [11, 12]. The addition of chick embryo extract (CEE) to cell culture medium provides essential growth factors for neural crest stem cells (NCSCs), which improve the shape and growth rate of cell lines [13, 14]. Researchers have explored alternative cell culture supplements to reduce or replace the use of fetal calf serum (FCS). One promising option is the use of egg and chick embryo extracts, which contain substances and factors necessary for animal cell growth and differentiation. Previous studies have demonstrated the stimulatory effects of these extracts on the development of animal cells in culture, including hybridoma cells and fibroblast cultures. These findings suggest that the liquid derived from various compartments of fertilized eggs can serve as a suitable supplement to replace FCS in cell culture media [15, 16]. Therefore, considering the advantages of egg yolk extract and chick embryo extract mentioned above and their cost-effectiveness, EYE and CEE are considered as a promising supplements for creating favourable conditions for cell growth. This would help to act as an alternative source of supplement due to its accessibility, easy Page 2 of 9 to produce and utilizes non-intrusive method of collection. This research focused on evaluating the efficiency of egg yolk extract (EYE) and chick embryo extract (CEE) as alternatives to fetal calf serum supplements in basic cell culture media. Materials and methods Egg incubation, egg yolk, and chick embryo extraction Specific pathogen-free (SPF) eggs were (...truncated)