Tricalcium bis(orthophosphate)

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Non-validated methods used

Data source

Reference

Reference Type:

publication

Title:

Studies on the biological value of inorganic phosphates

Author:

Gillis MB, Norris LC & Heuser GF

Year:

1954

Bibliographic source:

J. Nutr., Jan 1954; 52: 115 - 125

Materials and methods

Objective of study:

other: testing the availability of different phosphates from feed for chicks

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

chicks were feed with one of two defined diets. Diet one contains only a basal concentration of 0.04 % (400 ppm) phosphorus which support life in young chicks for only a few days. Diet 2 contained a basal phosphorus concentration of about 0.35 % (3500 ppm) which was enough to keep chicks alive for at least 4 weeks. Both diets were supplemented by different purified orthophosphates, pyrophosphates, bone meals as well as deflourinated phosphates, raw rock phosphates and metaphosphates to give relative phosphorus concentrations of 0.25, 0.3 and 0.35 % (2500, 3000, 3500 ppm). The diets were feed to 1 day old male White Leghorn chicks for 4 weeks. Subsequently animals were sacrifices and the left tibiae excised, incinerated and the ash weighted as a parameter for bone calcification.

GLP compliance:

no

Test material

Test material information

Test material form:

solid

Radiolabelling:

no

Test animals

Species:

other: chicken

Strain:

other: White Leghorn

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Housing: animals were individually housed in wire floored electrically heated battery brooders
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

no data

Duration and frequency of treatment / exposure:

continuous (via feed) for 4 weeks

Doses / concentrations

Remarks:

Doses / Concentrations:
equivalent of 0.25, 0.30 and 0.35 % (2500, 300, 3500 ppm) phosphorus in feed

No. of animals per sex per dose / concentration:

>= 10 per dose and substance

Control animals:

not specified

Positive control reference chemical:

no data

Details on study design:

no data

Details on dosing and sampling:

no data

Statistics:

no data

Results and discussion

Preliminary studies:

no

Toxicokinetic / pharmacokinetic studies

Details on absorption:

see table 1 for results of the bone calcification as a parameter for phosphate absorption

Details on distribution in tissues:

no data

Details on excretion:

no data

Metabolite characterisation studies

Details on metabolites:

no data

Any other information on results incl. tables

Table 1: Comparative biological values of inorganic phosphates

Reagent grade orthophosphates
Beta-tricalcium phosphate	100
Dicalcium phosphate	98
Monocalcium phosphate	113
Potassium acid phosphate	109
Sodium acid phosphate	101
Bone products
Steamed bone meal
Sample A	100
Sample B	100
Sample C	100
Sample D	95
Sample E	94
Sample F	90
Sample G	70
Foreign bone meal	87
Spent bone char	84
Bone ash	89
Pyrophosphates
Alpha Ca pyrophosphate	0
Beta Ca pyrophosphate	0
Gamm Ca pyrophosphate	0
Vitreous ca pyrophosphate	20
Na pyrophosphate, decahydrate	57, partly toxic
Feed grade dicalciumphosphates
Sample A	97
Sample B	97
Sample C	96
Sample D	89
Defluorinated phosphates
Calcined	94
Fused	82
Precipitated	99
Raw Rock Phosphates
Curacao Is. Phosphate	87
Fla. Land pebble rock	50
Tennese brown rock	25
Colloidal phosphate	25
Acid pyrophosphates
Calcium acid pyrophosphate A	67
Calcium acid pyrophosphate B	50
Metaphosphates
Beta Ca metaphosphate	0
Gamma Ca metaphosphate	0
Vitreous Ca metaphosphate	45
Sodium metaphosphate	28
Potassium metaphosphate	0

in italics: values were determined with diet 2 as with diet 1 the bioavailability of phosphates was to low leading to a drastic mortality

- based in these results the following conclusions were drawn by the authors:

- The pure orthophosphates had a high bioavalability.

- Feed grade materials with bioavailability of phosphate were dicalcium phosphate, defluorinated phosphate and steamed bone meal. The bioavailability of phosphate from spent bone char, bone ash and inported bone meal was lower but sufficient.

- The bioavailability of phosphate from pyrophosphates and metaphosphates was low to zero

- Of the rock products only Curacao Island phosphate had a satisfactory bioavailability.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): no data
The bioavaiability of phosphate from different phosphates was tested in a bioassay where young male Leghorn White chicks were fed for 28 diet a defined diet that was low in phosphate with a defined supplement of the respective phosphate. The ash of the tibiae was weighted as parameter for bone calcification and hence the bioavailability of phosphate.
- The pure orthophosphates had a high bioavalability.
- Feed grade materials with bioavailability of phosphate were dicalcium phosphate, defluorinated phosphate and steamed bone meal. The bioavailability of phosphate from spent bone char, bone ash and inported bone meal was lower but sufficient.
- The bioavailability of phosphate from pyrophosphates and metaphosphates was low to zero
- Of the rock products only Curacao Island phosphate had a satisfactory bioavailability.

Executive summary:

In the present study (Gillis 1954) the bioavaiability of phosphate from different phosphates was tested in a bioassay where young male Leghorn White chicks were fed for 28 diet a defined diet that was low in phosphate with a defined suppment of the respective phosphate. The ash of the tibiae was weighted as parameter for bone calcification and hence the bioavailability of phosphate.

- The pure orthophosphates had a high bioavalability.

- Feed grade materials with bioavailability of phosphate were dicalcium phosphate, defluorinated phosphate and steamed bone meal. The bioavailability of phosphate from spent bone char, bone ash and inported bone meal was lower but sufficient.

- The bioavailability of phosphate from pyrophosphates and metaphosphates was low to zero

- Of the rock products only Curacao Island phosphate had a satisfactory bioavailability.