Menadione nicotinamide bisulphite as a source of vitamin K and niacin activities for the growing pig

When compared with other menadione derivatives such as menadione sodium bis ulphite (MSB), menadione nicotinamide bisulphite (MNB), an organic salt com bining menadione and nicotinamide, shows better stability towards physical and chemical factors once it is added to pre-mixes or foods. The present wo rk evaluates the bioavailability of the two vitamins present in this compou nd and toxicity in the pig. To assess vitamin bioavailability, pigs were gi ven small amounts of food containing MNB or equivalent amounts of MSB and n icotinamide in the free form. Menadione and nicotinamide concentrations in blood samples drawn at set times after the diets were given did not reveal any significant differences between the two modes of administration. Haemat ic levels of both vitamins in animals receiving MNB, or MSB and nicotinamid e, were after 2, 4, 8 and 12 h higher (P < 0.001) than those of untreated a nimals. The tolerance level to MNB was evaluated in pigs given diets contai ning graded amounts of MNB (100, 500, 2500 mg/kg) for 28 days. No significa nt (P > 0.05) differences were recorded in live weight,food intake and gain /food ratio in pigs given these diets when compared with those given an uns upplemented diet. Haemoglobin and bilirubin levels did not differ between a nimals given various amounts of MNB and control animals. Plasma aspartate a minotransferase (AST) and alanine aminotransferase (ALT) activities in pigs given 100 mg/kg of MNB did not show significant differences when compared with those observed in pigs given an unsupplemented control diet. In pigs o n the diets supplemented with 500 and 2500 mg/kg of MNB there was a signifi cant increase in the two enzymatic activities as compared with controls (P < 0.001 and P < 0.02). In the case of ALT this had disappeared by 28 weeks. MNB is a good source of vitamin K for the pig and does not appear to have any adverse effects, even when administered at levels higher than those nor mally used in pig food supplementation.