[Experimental study of fluorosis in lambs]

Eighty-four lambs weaned at birth were randomised to three groups, each of 28 animals. The amount of fluoride contained in the feed was carefully assessed. Two groups were administered with sodium fluoride. The dose was calculated so as to administer a quantity of fluoride close to the quantity that lambs would ingest in consuming alfalfa containing from 125 to 250 ppm fluoride. The daily amount of fluoride administered to the 1st group rose progressively between week 3 and week 8 from 0.45 to 2 mg/kg/day, then remained fixed until the animals were slaughtered. Group 2 received double amounts: from 0.90 mg/kg/day to 4 mg/kg/day between week 3 and week 8, at which level the amount was fixed. The treatment had no effect on the growth of the lambs: at week 17 their average weight was about 29 kg. Plasma levels of ionic fluorine rose steadily up to week 9, at which they remained fixed at about 0.40 mg/l in group 1 and 0.75 mg/l in group 2, whereas they ranged between 0.10 and 0.15 mg/l in the controls. Ionic fluorine averaged 28% of the total fluoride in the controls, 42% in group 1 and 47% in group 2. Fluoride levels in the bones were very high (up to 2760 ppm in the mandibles in group 2). Reversely, fluoride levels in the muscles were very low: 1.00 ppm in group 2. The biochemical paremeters calcium, phosphorus, magnesium, transaminases, phosphatases and gamma glutamyl transferases greatly varied in relation to the age of the animal but were not affected by fluoride intake.