Ochratoxin A cytotoxicity on Madin-Darby canine kidney cells in the presence of alpha-tocopherol: Effects on cell viability and tight junctions.

Ochratoxin A (OTA) is a potent nephrotoxic fungi metabolite that affects animal and human health. At the cellular level, OTA is able to alter functions and viability by several mechanisms of action. Several strategies to counteract its toxicity have been studied. We investigated the role of α-tocopherol in counteracting OTA oxidative damage in Madin-Darby canine kidney (MDCK) cells by pre-incubating the cells for 3 hr with the antioxidant (1 nm, 10 µm) and then adding OTA (0-1.2 µg/ml) for the following 24 hr. Cell viability, lactate dehydrogenase (LDH) release, TUNEL staining and occludin and Zo1 localization by immunofluorescence were determined. Here, 1 nm α-tocopherol was shown to significantly reduce (p < .05) the cytotoxicity, LDH release and apoptotic rate induced by OTA. The presence of the antioxidant at the same concentration maintained the localization of occludin and Zo1 in the rim of the MDCK cells after the 24-hr OTA exposure. These results indicate that a low concentration of α-tocopherol could block OTA toxicity, supporting its defensive role in the cellular membrane.

A Survey of Dog Owners' Attitudes toward Treats.

Commercially available dog treats have become very popular and a common part of the pet's diet, yet very little is known about peoples' opinions and feeding habits; therefore, a survey was shared on a popular social network.Most of the self-selected interviewed owners (n = 1833, 83%) use treats regularly, mainly to reward their dog's behavior or during training-sports activities. Owners usually buy several types of treats, of which biscuits and dental care sticks are the most common, and usually hand out one to five pieces to their dogs every day. Most owners read the labels of the treats to seek the ingredients list and the claimed health benefits; contrarily, many owners look for non-nutritional values, such as flavor (n = 321, 18%), brand (n = 72, 4%) or shape (n = 46, 3%). Seventy-five percent of the owners (n = 1369) follow the feeding instructions provided by the producers on the label.Treat feeding is a common practice among dog owners and there is great variability among regimens (e.g., types and quantities provided). Understanding the owner's attitudes could help veterinarians educate them to manage treats in the dog's diet.

Rumen-protected choline and vitamin E supplementation in periparturient dairy goats: effects on milk production and folate, vitamin B12 and vitamin E status.

We investigated the effects of rumen-protected choline (RPC) and vitamin E (VITE) administration on milk production and status of folate, vitamin B12 and vitamin E during the periparturient period of dairy goats. Forty-eight Saanen multiparous goats were selected for the 72-day experiment, being moved to a maternity pen 30 days before expected parturition and assigned to one of the four experimental groups: control (CTR), no choline or vitamin E supplementation; choline (RPC), supplemented with 4 g/day choline chloride in rumen-protected form; vitamin E (VITE), supplemented with 200 IU/day vitamin E in rumen-protected form; and choline and vitamin E (RPCE), supplemented with 4 g/day RPC chloride and 200 IU/day vitamin E. Supplements were administered individually before the morning feed to ensure complete consumption, starting 30 days before kidding and continuing for 35 days after. During the experiment, milk yield and 4% fat-corrected milk (FCM) yield were, respectively, 210 and 350 g/day higher in RPC-supplemented goats than in non-supplemented goats. Milk fat concentration and fat yield were also increased by RPC treatment. Milk yield and composition were unaffected by vitamin E supplementation. There were no significant interactions between RPC and VITE for any of the variables measured. Plasma metabolites did not differ between treatments before and after kidding except that plasma folate at parturition was higher in RPC-supplemented goats. Neither choline nor vitamin E affected vitamin B12 plasma concentrations, while a time effect was evident after the second week of lactation, when B12 levels in each treatment group started to increase. Vitamin E administration resulted in plasma α-tocopherol levels that were 2 to 2.5 times higher than in non-supplemented goats. Overall, these results suggest that greater choline availability can improve milk production and methyl group metabolism in transition dairy goats.

Evaluation of the protective effects of alpha-tocopherol and retinol against ochratoxin A cytotoxicity.

Ochratoxin A (OTA), a mycotoxin frequently present in food and feedstuffs, produces a wide range of toxic effects, including cell death via lipid peroxidation. In one human and four animal cell lines we determined the half lethal concentration (LC50) of OTA, its effect on reactive oxygen species (ROS) production, and its ability to induce cytochrome p450 activity. We also examined the protective effect of alpha-tocopherol and all-trans-retinol in the most sensitive cell lines (i.e. bovine mammary epithelia, for which LC50 was 0.8 microg/ml (24 h), and Madin Darby canine kidney, for which LC50 was 4.3 microg/ml (48 h)). Pre-incubation for 3 h with either antioxidant significantly (P<0.05) ameliorated the OTA-induced reduction in cell viability and significantly decreased (P<0.05) ROS production. These findings indicate that oxidative stress is an important factor in OTA cytotoxicity. Supplementation with antioxidant molecules may counteract the short-term toxicity of this mycotoxin.