Oral vaccination through voluntary consumption of the convict grouper Epinephelus septemfasciatus with yeast producing the capsid protein of red-spotted grouper nervous necrosis virus.

•Recombinant yeast producing RGNNV capsid protein was used as oral vaccine.•The recombinant yeast was prepared in freeze-dried form after disruption.•The fish voluntarily consumed feed containing the lysed recombinant yeast.•The fish immunized produced anti-RGNNV neutralizing antibody titer of >103.•The fish immunized showed reduced mortality against RGNNV challenge.