title: Biological chick procedure to determine fluoride availability in sepiolite.
abstract: 1. A modified fluoride (F) bioassay procedure based on the method of standard additions and using chicks was tested for the determination of F availability in sepiolite. Chicks were distributed between a control group fed on a basal diet and experimental groups fed on this diet supplemented with 100, 200 or 300 mg/kg F as sodium fluoride. A further group was fed on the basal diet plus 2 g/kg sepiolite. 2. Body weight gain and food consumption during a 60 or 90 d study were similar for all treatments. 3. Ileal digestibility of F from the basal diet or from the diet supplemented with 200 mg/kg F as sodium fluoride was higher (0.907) than for chicks fed on the sepiolite diet (0.152). 4. Increases in the F contents of tibia ash were linearly related to dietary F concentration as sodium fluoride. 5. F contents of tibiae from the sepiolite group (at 60 or 90 d of age) were plotted against tibia F concentrations from groups receiving additional sodium fluoride in the diet. A weighted regression was performed. The values obtained for the relative available F from sepiolite were 0.213 and 0.150, respectively, at 60 and 90 d of age.
authors.affiliation: Instituto de Alimentación Animal del Consejo Superior de Investigaciones Científicas, Ciudad Universitaria, Madrid, España.
authors.forename: F
authors.initials: F
authors.lastname: Tortuero
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000378:metabolism*; D004063:Digestion; D004435:Eating; D005459:Fluorides / Q000493:pharmacokinetics*; D007082:Ileum / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism*; D017633:Magnesium Silicates; D008297:Male; D009753:Nutritive Value; D012824:Silicic Acid / Q000378:metabolism*; D013977:Tibia / Q000378:metabolism
chemical_list: D017633:Magnesium Silicates; D012824:Silicic Acid; C001671:magnesium trisilicate; D008274:Magnesium; D005459:Fluorides