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Although the flavonol quercetin is used as a supplement in commercial dog food, data on quercetin bioavailability in dogs are not available. Thus, we investigated quercetin bioavailability (measured as area under the concentration -time curve) in nine adult beagle dogs at an oral dose of 10 mg/kg body weight (b.w.). The major fraction (. 80 %) of flavonols circulating in blood plasma were conjugated metabolites of quercetin. The absolute bioavailability of quercetin (i.e. the fraction that reaches the systemic circulation) was only about 4 %. We also compared the oral bioavailability between the aglycone quercetin and its more often used glucorhamnoside (rutin) and 3-O-glucoside (isoquercitrin) at an equimolar dose of 30 mmol/kg b.w. (corresponding to 10 mg quercetin/kg). Quercetin and isoquercitrin were mainly absorbed in the small intestine with isoquercitrin being one and a half times more bioavailable than quercetin. Maximal plasma concentration after isoquercitrin treatment was 0·89 (SEM 0·07) mmol/l. Although quercetin absorption from rutin was delayed, relative bioavailability was not lower than from the aglycone itself. The latter observation is in clear contrast to findings in human subjects, pigs or rats and might indicate that rutin is a better source of quercetin in dogs than in other species. However, potential in vivo quercetin effects beyond the gastrointestinal tract are limited by the intensive metabolism as well as by the rather low bioavailability of this flavonol.Quercetin glycosides: Quercetin: Dogs: Bioavailability: Flavonoids Plant flavonoids including the flavonol quercetin have become increasingly popular as dietary supplements in recent years. These compounds have been suggested to have various beneficial effects like preventing cancer, suppressing inflammation or decreasing fat absorption (1) . Quercetin, an effective antioxidant in vitro, is added to certain commercial dog foods and marketed as a compound preventing or improving a multitude of age-related diseases that are associated with increased oxidative stress. In order to evaluate potential effects of such compounds in vivo, a sound knowledge of their bioavailability and metabolism is prerequisite. In rats and pigs, the absolute bioavailability (i.e. the fraction of an ingested compound that reaches the systemic circulation) of unchanged quercetin was only 5 % and , 1 %, respectively (2,3) . However, the major fraction of plasma metabolites with an intact flavonol structure consists of methylated, glucuronidated and sulphated derivatives of quercetin (4 -6) . Taking also these metabolites into consideration, the absolute bioavailability of quercetin was noticeably higher with 59 and 17 % for rats and pigs, respectively (2,3) . Peak plasma concentrations after oral quercetin doses of 10 or 50 mg/kg body weight (b.w.) were in the low mmol/l range in these studies. This was also true for human subjects that ingested up to 200 mg of the flavonol in a single dose (7) .In plants, flavonols like quercetin occur mainly as O-glycosides ...

SUMMARYThe scope of this reflection paper was to review the latest research on the risk of MRSA infection and colonization in animals. Attention focused on occurrence, risk factors for colonization and infection, and human contact hazard for livestock, horses, and companion animals. Whereas the clonal relationship between MRSA strains of CC398 is straightforward in livestock this is less obvious in horses. Small companion animals typically share MRSA strains that seem to exchange with a human reservoir. Management and therapeutic options have been suggested for livestock, horses, companion animals, as well as instructions on safety measures for persons in contact with animals. Conclusions were drawn with emphasis on future research activities, especially to confirm the apparent evolution of the organism and to demonstrate efficiency of control strategies.

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BackgroundHorses develop recurrent airway obstruction (RAO) that resembles human bronchial asthma. Differentiated primary equine bronchial epithelial cells (EBEC) in culture that closely mimic the airway cells in vivo would be useful to investigate the contribution of bronchial epithelium in inflammation of airway diseases. However, because isolation and characterization of EBEC cultures has been limited, we modified and optimized techniques of generating and culturing EBECs from healthy horses to mimic in vivo conditions.ResultsLarge numbers of EBEC were obtained by trypsin digestion and successfully grown for up to 2 passages with or without serum. However, serum or ultroser G proved to be essential for EBEC differentiation on membrane inserts at ALI. A pseudo-stratified muco-ciliary epithelium with basal cells was observed at differentiation. Further, transepithelial resistance (TEER) was more consistent and higher in P1 cultures compared to P0 cultures while ciliation was delayed in P1 cultures.ConclusionsThis study provides an efficient method for obtaining a high-yield of EBECs and for generating highly differentiated cultures. These EBEC cultures can be used to study the formation of tight junction or to identify epithelial-derived inflammatory factors that contribute to lung diseases such as asthma.