Low Doses of Ochratoxin-A Decrease IgY and IgA Production in Broiler Chicks

Abstract

The mycotoxin, ochratoxin-A (OTA), produced by some fungi, and is a natural contaminant of many foods and animal feeds worldwide. Due to its toxic effects, the recommended maximum daily intake of OTA for poultry feeds is 0.1 mg OTA/kg (ECR2006/575/EC); this dose does not induce changes in hepatic/renal parameters, but decreases thymus size and serum globulin concentrations. Accordingly, in this study, we assessed quantitatively the total circulating IgY and IgA serum levels, in chicks consuming a 0.1 mg OTA/kg diet (limit) and higher doses (0.3–1.1 mg OTA/kg diet) for 14 or 21 days. We also evaluated other immunological parameters (thymus, bursa of Fabricius, and spleen weights and leukocyte profiles) at day 21. Decreased IgY serum levels were observed in all OTA-treated groups (p < 0.05). In the low-dose group, IgA levels were decreased on day 21, but not on day 14. The size of the thymus and the bursa of Fabricius was decreased in all OTA-treated groups (p < 0.05), whereas reduced spleen size and altered leukocyte profiles were detected only in the high-dose group (p < 0.05). We concluded that chronic exposure to OTA, even at the recommended highest dose, affected IgY and IgA production in chicks.

Effects of Subcutaneous Ochratoxin-A Exposure on Immune System of Broiler Chicks

“…Herein, chicks exposed to OTA through the subcutaneous route demonstrated a reduction in the bursa and thymus similar to that previously observed by the oral route at the lowest OTA dose (0.1 mg/kg feed) [16], but differently, the subcutaneous route also induced a reduction in spleen size at the lowest OTA dose (0.1 mg/kg B.W.). As the oral contamination was performed on day 1 [16] and the subcutaneous contamination on day 5, the immune system of the chicks was already more developed. Despite this, the spleen, a peripheral organ, was affected by a lower dose, suggesting greater sensitivity of this organ when OTA exposure occurs through a subcutaneous route.…”

“…Possibly as a consequence of a decrease in the size of the bursa and thymus, central lymphoid organs that are responsible for lymphocytes production [12], similarly to that previously observed for oral exposure [16], presented a decreased percentage of circulating lymphocytes by the subcutaneous route. The majority of previous studies concerning lymphopenia have investigated the result of OTA through oral exposure and also with higher doses of OTA [13,31].…”

“…Interestingly, although heterophils increased after oral exposure [16,32] they were significantly reduced in groups exposed to OTA subcutaneously. Heterophils, like mammalian neutrophils, are phagocytic cells and form the first line of natural defense against invading microbial pathogens [33].…”

“…Regarding immunosuppression, OTA suppresses the immune system of chickens, causing atrophy and a decrease in overall weights of the immunological organs including both primary lymphoid organs, the thymus and bursa of Fabricius, and peripheral lymphoid organs such as the spleen [7]. The central lymphoid organs are lymphocyte producing organs [12] and severe lymphocytopenia, as well as depression of antibody response, have been observed in poultry exposed to OTA [6,13,14], in high [6,13,14] or low doses [15,16], such as the optimum daily value of OTA for poultry feed recommended by the European Commission Recommendation 2006/576/EC [17].…”

Grape Pomace Valorization: A Systematic Review and Meta-Analysis

“…Consequently, if grape pomace is used as the ingredient in certain food commodities, it can represent a health hazard due to the possible presence of ochratoxin A. Its thermal stability even at temperatures up to 250 • C makes it difficult for elimination in heat-processed food [41]. The levels of the ochratoxin A, in analyzed grape pomace samples, were approximately 0.07 µg/kg.…”