Therapeutic efficacy evaluation of florfenicol against Vibrio harveyi in snubnose pompano (Trachinotus blochii)

Bacterial diseases cause severe economic losses in aquaculture. Well-timed therapeutic interventions with suitable doses of antimicrobials are crucial for minimizing these economic losses (Stentiford et al., 2012). For this, knowledge of the drug efficacy against major pathogens of each targeted host is critical so that overdosing and using ineffective drugs can be avoided. Nevertheless, information on the in vivo efficacy of antimicrobials in most tropical marine fish is lacking. Among the four recommended antimicrobials for aquaculture by USFDA (2008), florfenicol (FFC) is usually preferred. In vivo efficacy of FFC against certain aquatic pathogens, including Vibrio harveyi (Parmar, Yusufzai, Parmar, Nanjiyani, & Chavda, 2018) has been proved in several freshwater fish (Darwish 2007; Gaunt et al., 2004; Soto, Endris, & Hawke, 2010), but in a limited marine fish (Feng, Ruan, Chen, Luo, & Dong, 2018; Kogiannou, Nikoloudaki, Katharios, Triga, & Rigos, 2021). Among the high-value cultivable marine tropical finfishes, Trachinotus blochii is a promising species (FAO, 2021). Incidences of infectious diseases, especially vibriosis, however, hamper successful farming practices. While biosafety and tissue residue of oxytetracycline were evaluated in T. blochii (Sharma et al., 2021), in vivo efficacy information is lacking in this species. Hence, the present study aimed to evaluate in vivo therapeutic efficacy of FFC in T. blochii against experimental V. harveyi infection