BIOLOGICALLY ACTIVE (IN-VIVO AND IN-VITRO) RECOMBINANT YELLOWTAIL KINGFISH (Seriola lalandi) FOLLICLE STIMULATING HORMONE

Pablo J. Sanchis-Benlloch 1, J. Nocillado 1, C. Ladisa1, J. Aizen 1, A. Miller2, M. Shpilman3, B. Levavi-Sivan 3, T. Ventura1, A. Elizur 1
 
1 Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Queensland, Australia; 2Clean Seas Tuna Ltd, Port Lincoln, SA, Australia; 3Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
E-mail: Pablo.Sanchis-Benlloch@research.usc.edu.au
 

Introduction

Yellowtail kingfish (Seriola lalandi, YTK) aquaculture is a growing industry worldwide owing to its fast growth, high flesh quality and suitability for culture in sea cages and recirculating aquaculture systems (Chen et al., 2006; Orellana et al., 2014; Poortenaar et al., 2001). In South Australia, YTK females take 4-5 years to reach sexual maturity (Sanchis-Benlloch et al., 2016). Currently, a genetic selection program is being undertaken to shorten its generation time and to increase genetic gain (Whatmore et al., 2013). As a first step towards advancing puberty or shortening generation time in YTK, we have generated a single chain recombinant yellowtail kingfish FSH (rytkFSH) using the yeast (Pichia pastoris) expression system (Hollenberg and Gellissen, 1997). Biological activity of the recombinant hormone was demonstrated by both in-vitro and in-vivo where sex steroid secretion was stimulated and gonadal development was promoted in immature YTK females, respectively.

Materials and methods

Recombinant ytkFSH was produced in yeast Pichia pastoris (Sanchis-Benlloch et al., 2016). The recombinant hormone was purified and tested in-vitro for its ability to bind a heterologous FSH receptor and for its potency to stimulate E2 in ovarian fragments. In addition, rytkFSH was injected intramuscularly in-vivo during 6 times with 10 day's interval at doses of 10-20 µg/kg into immature YTK females of 18 month-old.

Results

The biological activity of the recombinant hormone produced in Pichia pastoris was demonstrated by both in-vitro and in-vivo bioassays. Incubation of ovarian fragments with the recombinant ytkFSH stimulated E2 (Figure 1A). In-vivo trial in immature female YTK resulted in a significant increase of plasma E2 levels (Figure 1B) and development of oocytes (Figure 2). Modified from Sanchis-Benlloch et al., (2016).

Discussion and conclussion

The in-vitro and in-vivo resutls demonstrated that biologically active recombinant yellowtail kingfish FSH can be produced in yeast P. pastoris. The plasma estradiol levels and the ovarian histology suggest that rytkFSH administration in-vivo to immature female YTK acelerated gonadal development, although the response was still at the early stages of manifestation. In future studies, further research on administration at different periods of gonadal development could help define the most appropriate time frame of administration. Also, optimisation of dosage, frequency and duration of administration could facilitate achieving commercially applicable protocol for inducing early maturation in farmed female YTK and other late maturing species.

References

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Orellana, J., Waller, U., Wecker, B., 2014. Culture of yellowtail kingfish (Seriola lalandi) in a marine recirculating aquaculture system (RAS) with artificial seawater. Aquacult. Eng. 58, 20-28.

Poortenaar, C., Hooker, S., Sharp, N., 2001. Assessment of yellowtail kingfish (Seriola lalandi lalandi) reproductive physiology, as a basis for aquaculture development. Aquaculture 201, 271-286.

Sanchis-Benlloch, P.J., Nocillado, J., Ladisa, C., Aizen, J., Miller, A., Shpilman, M., Levavi-Sivan, B., Ventura, T. and Elizur, A., 2016. In-vitro and in-vivo biological activity of recombinant Yellowtail kingfish (Seriola lalandi) follicle stimulating hormone. General and Comparative Endocrinology. DOI: 10.1016/j.ygcen.2016.03.001.

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