Natural exposure of Martina Franca jennies and their foals to ochratoxin A

Ochratoxin A (OTA) is a worldwide occurring mycotoxin produced by Penicillium and Aspergillus fungi especially during unfavorable storage of cereals, with nephrotoxic, immunotoxic, teratogenic and reprotoxic activity. Although it has been shown that monogastric animals have high sensitivity to OTA, no data are available on natural exposure of Martina Franca jennies and their foals to this mycotoxin during late pregnancy and after delivery. Feed and blood samples were collected from January to September 2018, every 15 days from 7 jennies and their foals two months before and three months after delivery. Feed samples were comminuted/homogenized and analyzed by the AOAC Official method No. 2000.03 (Entwisle et al, 2000) for the determination of OTA in barley based on immunoaffinity column clean up of extracts and HPLC/FLD detection, with minor modifications. The quantification limit was 0.3 ng/g. The OTA extraction and determination of blood samples followed the protocol provided by the trademark of ELISA kit, with a detection limit of 50 ng/L. Out of 53 tested feed samples, 68% showed OTA levels lower than the quantification limit, 26% had levels ranging from 0.3 to 0.7 ng/g and 6% ranging from 1.4 to 2.7 ng/g. The analysis of each cereal component present in the feed showed similar low OTA levels (0.15-0.18) in bran, corn flake and soy, whereas barley and oat resulted uncontaminated (detection limit of 0.1 ng/g). Toxin concentrations were far below the guidance values of OTA in feed materials reported by the Commission Recommendation 2016/1319. Total blood samples collected from jennies and foals were 67 and 34, respectively. In jennies, the OTA incidence rate of positive (with OTA levels higher than the detection limit) blood samples was 7.3%, with median value of 114 ng/L and range from 51 to 6,000 ng/L. No significant differences of OTA serum levels were found among jennies, but a season-effect on the levels of OTA in the blood was found with significant increases from 10 to 60 times in 75% of the positive samples collected from May to September. Concerning foals, the number of positive blood samples were 17 with the incidence rate of 50%. Median value of OTA in positive samples was 134 ng/L, ranging from 79 to 4040 ng/L. No placental transfer of OTA was observed in all tested jennies and no influence on pregnancy length and health of foals was observed.