Effects of florfenicol on body weight, intestinal inflammatory response, intestinal fluid metabolism and microorganisms in broilers.

IMPORTANCE: Although antibiotics can prevent and treat diseases, their overuse can be harmful. Despite this, the effects of orally administered florfenicol on intestinal health in broilers are unclear. OBJECTIVE: This study examined oral florfenicol's effects on intestinal function in broilers to guide its clinical use. METHODS: One hundred and twenty Arbor Acres broilers (8-d-old) were divided randomly into the control (N) and florfenicol groups (F). The broilers in group F were fed 100 mg/kg body weight florfenicol for seven days. On day 15, the broilers were euthanized and sampled to analyze fluid metabolism-related genes and proteins, jejunal morphological and microbiota. RESULTS: The results revealed a decrease in body weight and an increase in diarrhea rate in broilers in group F compared to group N. The villus length and villus length/crypt depth (V/C) of the jejunum were lower in group F than in group N, whereas the crypt depth was higher. The levels of tumor necrosis factor α, Toll-like receptor 4, lipopolysaccharide, nuclear factor kappa-B, interleukin (IL)-6 and IL-10 in group F were higher in group F than in group N, whereas the levels of cyclic adenosine monophosphate and aquaporins (AQP) 4 and AQP5 were lower. Proteobacteria were more abundant in group F than in group N, whereas Firmicutes, Bacteroidetes, and Actinobacteria were less abundant. CONCLUSIONS AND RELEVANCE: Oral florfenicol might adversely affect the intestinal mucosa, intestinal mucosal immune system, intestinal microbiota balance, and water metabolism in broilers. This study provides a theoretical basis for the rational use of florfenicol.