Effect of Codon Optimisation on the Production of Recombinant Fish Growth Hormone inPichia pastoris

Abstract

This study was established to test the hypothesis of whether the codon optimization of fish growth hormone gene (FGH) based onP. pastorispreferred codon will improve the quantity of secreted rFGH in culture supernatant that can directly be used as fish feed supplements. The optimizedFGHcoding sequence (oFGH) and native sequence (nFGH) of giant grouper fish (Epinephelus lanceolatus) were cloned intoP. pastorisexpression vector (pPICZαA) downstream ofalcohol oxidasegene (AOX1) for efficient induction of extracellular rFGH by adding 1% of absolute methanol. The results showed that recombinantP. pastoriswas able to produce2.80±0.27 mg of oFGH compared to1.75±0.25of nFGH in one litre of culture supernatant. The total body weight of tiger grouper fingerlings fed with oFGH increased significantly at third (P<0.05) and fourth weeks (P<0.01) of four-week experiment period compared to those fed with nFGH. Both oFGH and nFGH significantly enhanced the final biomass and fish survival percentage. In conclusion, codon optimization ofFGHfragment was useful to increase rFGH quantity in the culture supernatant ofP. pastoristhat can be directly used as fish feed supplements. Further studies are still required for large scale production of rFGH and practical application in aquaculture production.