Bioavailability of Fluorine in Sepiolite for Laying Hens

Abstract

The purpose of the present work was to compare the bioavailability of structural fluorine contained in sepiolite and in sodium fluoride for laying hens. Three hundred 27-wk-old laying hens were fed one of three diets: 1) a control based on corn, barley, and soybean meal containing 21 mg/kg of fluorine; 2) a sepiolite diet in which 2% sepiolite replaced 2% barley in the control diet and which contained 217 mg/kg of fluorine; and 3) a NaF diet, consisting of the same control diet to which NaF was added to contain 217 mg/kg of fluorine (the same level of F- as the sepiolite diet). The experiment ended when hens were 64 wk old. Fluorine concentration in the tibial bone of hens fed the NaF diet was four times higher than in the control, and twice as high in eggshell. In contrast, hens fed sepiolite had fluorine concentrations in tibial bone and eggshell not significantly higher than fluorine concentrations in the controls. These results indicate that fluorine from sepiolite was not available. The effects of the different diets on egg production, feed intake, feed conversion, egg weight, shell and interior egg quality, dry matter of feces, and body weight gain were also determined but no significant differences due to the dietary treatment were observed.

Scientific Opinion on the safety and efficacy of a preparation of bentonite‐and sepiolite (Toxfin® Dry) as feed additive for all species

“…The author found an ileal fluorine digestibility of 15% from sepiolite and 91% from NaF. A low bioavailability of fluorine from sepiolite was also confirmed by Nogareda et al (1990) in a study on laying hens (tibia and eggshell deposition as end-points) and by Chaso et al (1991) in lambs (plasma concentration as end-point).…”

“…39 Only in hens fed low energy diet with 3 % sepiolite, laying rate and egg mass/day were significantly reduced and the feed to egg mass ratio increased. Nogareda et al (1990) fed laying hens for 37 weeks with diets containing 0 and 2 % sepiolite. No effects of sepiolite on laying rate, feed intake, feed to egg mass ratio, egg weight, shell and interior egg quality, dry matter of faeces and body weight gain were found.…”

Safety and efficacy of a feed additive consisting of sepiolite for all animal species (Sepiol S.A and Tolsa, S.A)

“…The bioavailability of sepiolite (maximum fluorine content of 9,800 mg/kg) was studied in laying hens by comparing the absorption of fluorine given in diet as NaF or as sepiolite (Nogareda et al, 1990 ). Three groups of animals were administered with a control diet (basal diet containing 21 mg F/kg), a diet supplemented with NaF at 217 mg fluorine/kg or a diet containing sepiolite at 2% corresponding to 217 mg fluorine/kg.…”

Safety and efficacy of a feed additive consisting of Sepiolitic clay for all animal species (Mineria y Tecnologia de Arcillas SA ‐ MYTA)

“…The bioavailability of fluorine from sepiolite (maximum fluorine content of 9,800 mg/kg) was studied in laying hens by comparing the absorption of fluorine given in diet as NaF or as sepiolite (Nogareda et al, 1990). Three groups of animals were administered with a control diet (basal diet containing 21 mg F/kg), a diet supplemented with NaF at 217 mg fluorine/kg or a diet containing sepiolite at 2% corresponding to 217 mg fluorine/kg.…”