LYZ and infection: In this work, largemouth bass immunized with pcIL-34, pcHrp1 and pcHrp1+pcIL-34 induced higher serum lysozyme activity 14 days p.v. The augmentation of serum lysozyme activity was observed in vaccinated fish with pcIL-34, pcHrp1, and pcHrp1+pcIL-34, but not in PBS and pcDNA3.1(+), suggesting that lysozymes may be involved in the innate immune response and play a role in the elimination of N. seriolae at an early stage of infection in largemouth bass.