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Canine acute enteropathies (AE) are common morbidities primarily managed with supportive therapy. However, in some cases, unnecessary courses of antibiotics are empirically prescribed. Recent studies in humans have hypothesized the use of antioxidants as a possible alternative and/or support to antimicrobial drugs in uncomplicated cases. Considering the global need to reduce the antibiotic use, the aim of the study was to compare the oxidative burden of the diarrhetic population to that of healthy dogs. Forty-five patients suffering from uncomplicated acute diarrhea (AD) and 30 controls were screened for clinical and biochemical parameters, and serum redox indices (reactive oxygen metabolites, dROMs; serum antioxidant capacity, SAC; oxidative stress index, OSi). The average levels of dROMs in AD dogs were significantly higher (p < 0.001) than in healthy dogs, while SAC did not significantly differ between the two groups. However, the OSi values (ratio between dROMs and SAC) significantly increased (p < 0.001) in AD dogs compared to controls. The study demonstrates that canine AD could induce redox imbalance. Although its role in the etiopathogenesis and evolution of the disease should be further investigated, our results suggest that the improvement of the patient oxidative status, possibly through the dietary administration of antioxidants, could support the management of canine AE, reducing the use of antibiotics.

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.

Food-borne pathogens, including Escherichia coli, Staphylococcus aureus and Campylobacter jejuni, are prophylactically prevented in livestock by using commercially available antibiotics. The European Union has recently banned the use of prophylaxis use of antibiotics in animals since 2006 while urgently considers ways to reduce food-borne pathogens. The objective of this study was to propose a screening method for identifying natural compounds with anti-bacteria activity from twenty-six Thai-herbal plants. Antimicrobial activity was evaluated by an agar diffusion method, which allowed for the determination of the minimum inhibitory concentration (MIC). The results indicated that Thai-herbs have potent antimicrobial activity against E. coli, S. aureus and C. jejuni at bacteria suspensions of 2.0-3.0x109 CFU/ml. Interestingly, C. formosum had the highest antimicrobial activity against the three food-borne pathogens of E. coli, S. aureus and C. jejuni, which were isolated from the chicken-caecum. MIC values of C. formosum against E. coli, S. aureus and C. jejuni were 3.0 mg/ml, 3.0 mg/ml and 0.3 mg/ml, respectively. Other herbal plants also had antimicrobial activity against the three food-borne pathogens in this study. The herbal plants provide not only a natural source of anti-bacterial activity, but also anti-oxidant activity and anticancer properties. The application of using Thai-herbal plants compounds by adding them in animal feed is proposed. This may be a safe means of enhancing health and production of livestock and thus benefits humans and animals. Consequently, the selection of herbal plants, for use in preventing food-borne bacterial infection, is both interesting and worthwhile for food safety.