Subclinical doses of dietary fumonisins and deoxynivalenol alter the cecal microbiota of broiler chickens

Fusarium toxins are one of the most common contaminants in poultry diets. Co-occurrence of fumonisins (FUM) and deoxynivalenol (DON), even at a subclinical dose, negatively affects the production performance and intestinal integrity in broiler chickens. Loss of gut integrity can be expected to alter the intestinal microbiota composition. This study evaluated the effects of subclinical doses of combined mycotoxins on the cecal microbiota composition and diversity in broiler chickens. Broiler chickens were raised on 2 diets: starter (d 0–21), and grower diet (d 22–35). A total of 240 one-day-old chicks were randomly assigned to 2 treatments, each replicated in 8 pens with 15 birds per pen. The experimental treatments were control diet and 3 mg/kg FUM + 4 mg/kg DON contaminated diet. On d35, 3 mg/kg FUM + 4 mg/kg DON contaminated diet tended to decrease the body weight by 84 g compared with the control group (P = 0.06). Cecal contents were collected on d 21, 28, and 35. The bacterial compositions of the cecal contents were analyzed by Illumina MiSeq sequencing of the V3–V4 region of the 16S rRNA gene. Overall, microbial richness and diversity increased (P < 0.05) during the studied period (d 21–35). Cecal contents of birds in the 3 mg/kg FUM + 4 mg/kg DON group had greater (P < 0.05) microbial evenness and diversity (Shannon index), compared with the control group. Chronic exposure of 3 mg/kg FUM + 4 mg/kg DON decreased (P = 0.001) the relative abundance of Proteobacteria in the cecal content, compared with the control group. At the genus level, the cecal content of birds in the 3 mg/kg FUM + 4 mg/kg DON showed decreased (P < 0.05) relative abundances of Acinetobacter and Pseudomonas, and a tendency (P = 0.08) for a lower abundance of Thermincola compared with the control group. The present findings showed that dietary FUM and DON contamination, even at subclinical levels, altered the bacterial microbiota composition and diversity in the cecal content of the birds.

Key Words: Fumonisins, deoxynivalenol, mycotoxins, 16s sequencing, cecal microbiota.