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Ochratoxin A (OTA) is a mycotoxin produced by species of Penicillium and Aspergillus that can contaminate products of plant origin that are used as animal feed. Through oral exposure, this mycotoxin primarily affects the chicken gastrointestinal system. The present study evaluated the intestinal toxic effects of OTA and the introduction of L-tryptophan to alleviate these effects in chickens. One-day-old chicks were exposed to a single OTA dose (1.4 mg/kg body weight-b.w.) and treated with or without four daily doses of L-tryptophan (100 mg/kg b.w.). Duodenal villus height/crypt depth, fecal immunoglobulin A/immunoglobulin Y (IgA/IgY) levels, and duodenal positive immunoglobulin A cells (IgA + ) were evaluated by histology, ELISA, and immunohistochemistry, respectively, on the 14th day. There were significant changes in the duodenal villus height, crypt depth, and levels of fecal IgA/IgY and duodenal IgA + cells ( p < 0.05) in groups exposed to OTA. On the other hand, groups exposed to OTA and treated with L-tryptophan showed similar levels of villus height, IgA/IgY levels, and duodenal IgA + cells to those of the control group ( p > 0.05). In conclusion, exposure to a single dose of OTA orally induces changes in intestinal morphology, levels of IgA/IgY antibodies, and IgA + cells. Thus, treatment with L-tryptophan may be a valid alternative means to reduce the harmful effects of OTA on the intestinal mucosa, which requires further study.

Influenza A virus (IAV) causes an important respiratory disease in mammals and birds leading to concerns in animal production industry and public health. Usually, antibodies produced in mammals are employed in diagnostic tests. However, due to animal welfare concerns, technical advantages and the high cost of production, alternatives to the production of antibodies in mammals have been investigated. The aim of this study was to produce egg yolk immunoglobulin (IgY) in laying hens against a highly conserved protein (nucleoprotein- NP) of IAV and to evaluate the application of anti-NP IgY antibodies in virus detection by immunocytochemistry (ICC) and immunohistochemistry (IHC). Three laying hens of the White Leghorn line were inoculated seven times with a recombinant NP protein and their eggs collected seven days after the 3rd, 5th and 7th inoculations. Immunoglobulin Y antibodies were purified from egg yolk through precipitation with ammonium sulfate. The titers and specificity of the purified antibodies were determined by ELISA, western blotting, ICC and IHC. High levels of specific anti-NP antibodies were detected by ELISA after the 5th inoculation, reaching a peak after the 7th inoculation. The mean yield of total protein in yolk after the 7th inoculation was 13.5 mg/mL. The use of western blotting and ICC demonstrated that anti-NP IgY binds specifically to NP protein. Moreover, the use of anti-NP IgY antibody in ICC test revealed positive staining of MDCK cells infected with IAV of the three subtypes circulating in swine (H1N1, H1N2, and H3N2). However, no staining was observed in lung tissues through the IHC test. The data obtained showed that anti-NP IgY antibodies bound specifically to influenza virus NP protein, detecting the main virus subtypes circulating in swine, reinforcing their usefulness in the influenza diagnosis., (Copyright © 2018 Elsevier B.V. All rights reserved.)

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.