Factors affecting ascorbic acid biosynthesis in chickens: III. Effect of dietary fluoride on L-gulonolactone oxidase activity and tissue ascorbic acid (AsA) concentration.

The inconsistent beneficial responses to dietary ascorbic acid (AsA) may be due to dietary factors that alter biosynthesis or tissue turnover of AsA. It has been suggested on the basis of altered tissue AsA that dietary fluoride is a determinant of biosynthesis in chickens. Fluoride may enter the food chain of poultry via industrial contamination, feed ingredients and drinking water. The goal of this study was to ascertain whether dietary fluoride at 300 mg/kg influences l-gulonolactone oxidase (GLO) activity in commercial meat-type chickens. The experimental diet was fed from day-old to 3 weeks and responses measured. Growth and feed conversion were not affected by fluoride in the diet. Dietary fluoride neither inhibited nor enhanced GLO activity nor did it increase or decrease AsA concentration in plasma, liver, kidney, adrenal gland and muscle (pectoralis major). Tissue AsA concentration in ascending order was adrenal > liver > kidney > pectoralis major > plasma. The results are consistent with that reported for the rat and calculations based on the results eliminate fluorine contamination for the inconsistent responses of immature chickens to dietary AsA.