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Prof. Ahrar Khan

University of Agriculture, Faisalabad (UAF), Pakistan (click)

Research Area: Histopathology, Toxicopathology, Veterinary pathology

Speech title:IMMUNOSUPPRESSION INDUCED BY MYCOTOXINS

Abstract:

Mycotoxins (AFB1, OTA, DON, ZEN, T-2) are the second most important issue faced by the poultry industry after the high prices of feed throughout the world. Up to 25% of the world’s food crops significantly contaminated with mycotoxins at pre and postharvest time.  Several toxigenic species of Aspergillus, Penicillium, Fusarium, etc. produce mycotoxins.  These mycotoxins enter the human food chain through contaminated crops, eggs, meat and milk and become a one-health problem. Continuous high levels of mycotoxins lead to low performance, high mortality, hepatotoxicity, nephrotoxicity, teratogenicity, carcinogenicity, etc. not only in poultry and other animal species but also in humans.  Unremitting exposure results in immunosuppression by lymphocytic depletion in lymphoid organs.  These mycotoxins usually lead to decreased/depressed cellular and humoral immune response, antibodies response to sheep RBCs, the phagocytic capability of macrophages, natural killer cell activity, complement or interferon activity, cytokine expression, etc. Most probably, the mechanism of immunosuppression by these mycotoxins is that their active metabolites bind to DNA and lead to DNA adducts formation, which then impairs DNA dependent RNA polymerase activity and inhibits RNA protein synthesis/blocking transcription, and thus inhibiting protein synthesis.

In the presence of mycotoxins, even good quality vaccines will not respond properly. Significantly low serum IgG titer against the ND vaccine and mucosal IgA titer against the IB vaccine has been reported in chicken exposed to AFB1 as compared to the negative control. Similarly, low antibodies titer and depressed lymphocyte counts were recorded in AFB1 exposed birds. Progeny of breeder hens exposed to OTA showed low relative Bursa weights, depressed cellular and humoral immunity. Even chicks hatching from OTA exposed eggs showed depressed macrophage functions. Similarly, the immunosuppressive effects of trichothecenes (DON or T-2 toxin) have been reported. Even the efficacy of anti-coccidial drugs in the presence of DON, zearalenone, and fumonisins alters significantly.  From the above discussion, it is concluded that mycotoxins are immunosuppressive. The mycotoxins problem must be controlled from the field to the farm. We must opt for intervention strategies to keep mycotoxins levels to a minimum not only in poultry/animal feeds but also for human beings so that birds/animals/humans remain healthy.


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Prof. Vir Singh

GB Pant University of Agriculture and Technology, India/ Department of Environmental Science (click)

Research Area: Environmental Science, Agroecology


Speech title:Agroforestry for Ecological Integrity and Food Sovereignty in the Himalayan Mountains: An Agroecological Perspective

Abstract:

In the mountains, almost everywhere in the Hindu Kush-Himalayan Region, unlike in the plains, agriculture does not rely only on cultivated lands, but on farming systems or agroecosystems involving uncultivated lands (forests/ rangelands), cultivated lands, livestock and households. Agroforestry prevails in the rainfed cultivated lands.Agroforestry systems have potential to create a socioeconomic state of food sovereignty. Food security on sustained basis emanates from food sovereignty of a society. However, mountain areas, like the Indian Central Himalayas, continue to be net food importers rather than food secure. It is because in our agriculture policy framework, the emphasis is on annual crops, especially the food grain crops. Food security at local, national and even at global level is woven around three food grain crops, viz., wheat, rice and maize. The food security built upon these three crops is not, and cannot be, sustainable one. Intensive terracing followed by intensive cultivation of crop annuals induces catastrophic changes in the inherently fragile mountain ecosystems. Protection, conservation and ecological augmentation of uncultivated lands, an appropriate balance between uncultivated and cultivated lands, and adoption of agroforestry-centred and agrobiodiversity-based agroecological practices of food production will be phenomenal in ecological integrity and realize a state of food sovereignty in the ecologically sensitive, biodiverse, and marginality-ridden Himalayan mountains.




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