METABOLIC EFFECTS OF SHORT-TERM ADMINISTRATION OF FLUORIDE TO CALVES FED GRADED PROTEIN LEVELS IN THEIR DIETS

초록

In order to assess the influence of dietary protein intake on the susceptibility to fluoride (F) intoxication, 30 crossbred calves (6-8 months; 104 kg body weight) reared on high, medium, and low levels of dietary protein were exposed to either 0 or 200 mg/kg supplemental F (source: NaF) for a period of 105 days. A metabolism trial conducted at 97 days post-feeding revealed that the intakes of dry matter, digestible crude protein, and metabolizable energy were significantly (p<0.05) reduced with F exposure. The digestibility of organic nutrients other than crude fiber increased (p<0.05) with the F-supplemented diets. Calves exposed to F with the low protein diet had the lowest body weight gain and decreased nitrogen retention. The mean daily intake, excretion, and retention of F were higher (p<0.01) in the F-supplemented calves, irrespective of protein intake levels. Calves exposed to the low protein diet had a lower urinary F output, reflected by a proportionally higher retention of F. These findings indicate that diets low in protein may accentuate F retention and toxicity and retard growth in calves.

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