The Impact of Deoxynivalenol on Pigeon Health: Occurrence in Feed, Toxicokinetics and Interaction with Salmonellosis

Abstract

Seed-based pigeon diets could be expected to result in exposure of pigeons to mycotoxins such as deoxynivalenol (DON). Ingestion of low to moderate contamination levels of DON may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host-pathogen interactions and thus different outcome of infections. Here we demonstrate that DON was one of the most frequently detected mycotoxins in seed-based racing pigeons feed, contaminating 5 out of 10 samples (range 177-1,466 μg/kg). Subsequently, a toxicokinetic analysis revealed a low absolute oral bioavailability (F) of DON in pigeons (30.4%), which is comparable to other avian species. Furthermore, semi-quantitative analysis using high-resolution mass spectrometry revealed that DON-3α-sulphate is the major metabolite of DON in pigeons after intravenous as well as oral administration. Following ingestion of DON contaminated feed, the intestinal epithelial cells are exposed to significant DON concentrations which eventually may affect intestinal translocation and colonization of bacteria. Feeding pigeons a DON contaminated diet resulted in an increased percentage of pigeons shedding Salmonella compared to birds fed control diet, 87 ± 17% versus 74 ± 13%, respectively. However, no impact of DON was observed on the Salmonella induced disease signs, organ lesions, faecal and organ Salmonella counts. The presented risk assessment indicates that pigeons are frequently exposed to mycotoxins such as DON, which can affect the outcome of a Salmonella infection. The increasing number of pigeons shedding Salmonella suggests that DON can promote the spread of the bacterium within pigeon populations.

Fig 1. Chemical structure (insert) and plasma concentration-time profile of deoxynivalenol (DON) after single IV (n = 10) and PO (n = 10) administration of 0.3 mg DON/kg bodyweight to racing pigeons.

Values are presented as means + SD.

Fig 2. Peak area of deoxynivalenol-3alpha-sulphate (DON3S) at different time points after intravenous (IV) (n = 5) and oral (PO) (n = 5) administration of 0.3 mg DON/kg body weight to pigeons, as determined by high resolution-mass spectrometry.

Values are presented as means + SD.

Fig 3. Salmonella fecal shedding.

Pigeons were fed either a control diet or a DON contaminated diet for 28 days. Post inoculation with a pigeon-adapted Salmonella Typhimurium variant Copenhagen strain DAB69, Salmonella fecal shedding was assessed daily by counting the numbers of Salmonella in excreta samples. Results are presented as the mean number (+ SD) of CFU of Salmonella per gram of excreta and the percentage of pigeons shedding Salmonella per experimental group.

Fig 4. Salmonella numbers in organs.

Thirteen days post inoculation with Salmonella Typhimurium variant Copenhagen strain DAB69, birds were euthanized and organs were collected, homogenized, and examined for the number of CFU of Salmonella per gram of matrix. Results are presented as mean + SD.