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The treatment of choice for feline hyperthyroidism is the administration of the antithyroid drug methimazole. Both the endocrinopathy and the drug adverse reactions (e.g., hepatotoxicosis, gastrointestinal disorders, and renal injury) are partly due to oxidative stress and redox unbalance. This study investigated the free radical production and the impairment of the antioxidant barrier induced by methimazole in an in vitro model of feline renal epithelium. The protective effects of quercetin and resveratrol were also explored. CRFK cells were incubated with a methimazole concentration equivalent to the maximum plasma levels in orally treated cats (4 µM), in the presence or absence of either one of the two selected antioxidants at different time-points (up to 72 h). Cell viability, ROS production, GSH levels, and mRNA expression of antioxidant enzymes (i.e., CAT, SOD, GPx, and GST) were assessed. Methimazole impaired cell viability and increased ROS levels in a time-dependent manner. Similarly, GSH content and CAT, SOD, and GPx3 expression were higher compared with control cells. Such effects were significantly counteracted by quercetin. These results provide new insights about the mechanisms underlying the methimazole-related side effects frequently observed in hyperthyroid cats. They also support the use of quercetin in the management of feline hyperthyroidism.

Aflatoxin B1 (AFB1), the mainly Aspergillus fungi derived mycotoxin, is well known for its carcinogenic effects on liver, and frequently occurs in food supplies, leading to fatal consequences in both farm animals and humans. Poultry, one of the most important segments of agro-industry, has been demonstrated to be extremely sensitive to AFB1 intake, which results in chickens’ low performance, decreased quality of both eggs and meat and a negative economic feedback. Oxidative stress caused by AFB1 plays a crucial role in chickens’ kidney damage by generating lipid peroxidation accompanied by a concomitant increase in the antioxidant enzymes involved in ROS metabolism (NADPH oxidase isoform 4 (NOX4) and its regulatory subunit p47-phox). The aim of the present work was to investigate the benefits of dietary supplementation, in chickens affected by AFB1 mycotoxicosis, using a new Feed additive (FA) containing a mixture of a tri-octahedral Na-smectite with a ligno-cellulose-based material an antioxidant adjuvant. Exposure of AFB1-treated chickens to the feed additive induced a significant down-regulation of both NOX4 and p47-phox genes expression levels. This trend was confirmed by their protein expression, demonstrating the great potential of the FA to counteract oxidative stress. To conclude, these results could open new perspectives in the methods of feeding chickens, using eco-friendly dietary supplements able to reduce AFB1-induced mycotoxicosis and to ameliorate poultry performances.

Ochratoxin A (OTA) is a mycotoxin which represents an emerging problem for both animal and human health, due to its high presence in feed and foods. Exposure to OTA is associated with oxidative stress-induced nephrotoxicity. Therefore, the identification of new antioxidant or adsorbent substances with protective action constitutes one of the main challenges to reduce the negative effects induced by mycotoxins. For this purpose, we investigated the effect of two innovative feed additives, a bio-organoclay (CHS) and a mixture of a tri-octahedral Na-smectite with a ligno-cellulose based material (MIX) alone or in combination with OTA in kidneys of treated chickens. Real-Time PCR analyses for NADPH oxidase 4 (NOX) and p47-phox were performed to evaluate oxidative stress. Our results demonstrated an increase in NOX and p47-phox levels in OTA-treated chickens. Moreover, CHS, more than MIX, was able to reduce OTA-induced toxicity, restoring NOX levels. Taken together, these findings highlight the potential beneficial role of CHS in reverting OTA-induced nephrotoxicity in chickens and could lead to the production of healthier foods with beneficial consequences for human and animal health.