“…In general, humoral innate factors, like lysozyme and complement, are important antimicrobial factors. The greatest concentration of lysozyme activity is found in the HK of fish, due to the high numbers of leukocytes [7,[15][16][17][18]. Nile tilapia cultured in 24 ppt salinity for 2 and 4 weeks, or in 12 ppt salinity for 4 weeks, showed increased lysozyme activity [19].…”