Calcium dipropionate

Toxicity to reproduction

Administrative data

Endpoint:

toxicity to reproduction

Remarks:

other: Continuous mating for 80 days (up to 4 litters)

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

no data available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well-documented publication. In the current study, calcium was administered in the form of calcium carbonate. The carbonate ion is released as CO2 following reaction with gastric juice and is therefore toxicologically not relevant. The objective of the study was the evaluation of any effects of calcium.

Data source

Reference

Reference Type:

publication

Title:

The effects of additions of calcium carbonate to the diet of breeding mice. 1. Effects on reproduction and on the heart and thymus weights of the weanlings

Author:

Richards; M.B.; Greig, W.A.

Year:

1952

Bibliographic source:

British Journal of Nutrition 6: 265-280

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

The effect of the different levels of CaCO3 on the reproductive performance of mice and the development of the offspring (as judged by the number of young born and reared as well as by the mortality observed during weaning) was tested. Two experiments were conducted.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Calcium carbonate

EC Number:

207-439-9

EC Name:

Calcium carbonate

Cas Number:

471-34-1

Molecular formula:

CaCO3

IUPAC Name:

calcium carbonate

Details on test material:

- Name of test material (as cited in study report): Calcium carbonate
- Physical state: solid
No further details are given.

Test animals

Species:

mouse

Strain:

Swiss

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: (P) 7 weeks
- Diet: ad libitum, each breeding female was given basal diet up to the age of 7 weeks, and was then given the appropriate experimental diet a week before being mated
- Water: ad libitum, supplemented with fresh whole milk to the mated pairs of adult mice
No further details are given.

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

DIET PREPARATION
- Mixing appropriate amounts with basal diet: Three levels of CaCO3 were added to a slightly modified Sherman B diet (diet 2). Diet 2 (basal diet) consisted of ground whole wheat 66 %, dried whole milk 33 % and NaCl 1 %.
The basal diet 70 was formed drom diet 2 by substituting 6 g maize starch for 6 g wheat, thus reducing the vitamin B content without increasing the protein.
The basal diet 74 was derived from diet 2 by substituting 6 g casein for 6 g wheat, thus reducing the vitamin B content but this time increasing the protein. The basal diet 78 was derived from diet 2 by substituting 5 g casein.
Diets were completed by the addition of CaCO3 at differnt rates.

No further details are given.

Details on mating procedure:

Females were mated with a male of the same age. Mating of litter-mate brothers and sisters was avoided. The method of continuous monogamous mating was used.

- M/F ratio per cage: 1/1
- Length of cohabitation: 80 days
- Proof of pregnancy: no data
- Further matings after two unsuccessful attempts: no data
- After successful mating each pregnant female was caged (how): no data
- Any other deviations from standard protocol: Parental reproductive parameters (oestrus cyclicity, sperm parameters) were not explicitly investigated. Also see below for any other parameters not addressed. This is not a guideline study, pre-dating any official test guidelines.

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

No details available

Duration of treatment / exposure:

Continuously until sacrifice (the observations were ended by killing the litters on weaning at 21 days of age.)

Frequency of treatment:

Continuously

Details on study schedule:

No details are given.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0.5 g/100g
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
1.0 g/100g
Basis:
nominal in diet

Doses / concentrations 3

Remarks:

Doses / Concentrations:
2.0 g/100g
Basis:
nominal in diet

No. of animals per sex per dose:

4 female mice were allocated to each group in Experiment I
8 female mice were allocated to each group in Experiment II

Control animals:

yes

Details on study design:

No further details are given.

Positive control:

No positive control substance was tested.

Examinations

Parental animals: Observations and examinations:

No details if observation of the parental animals were made are reported.

Oestrous cyclicity (parental animals):

No data available

Sperm parameters (parental animals):

No data available

Litter observations:

The effect of the diets on reproduction was judged by the number and weight of the young reared in a given period.
In Experiment I the females were maintained on the diets long enough to rear any litters that had been conceived.
In Experiment II sufficient time was allowed for rearing only two litters.
The observations were ended by killing the litters on weaning at 21 days of age. Post mortem examinations were made.
The heart and thymus weights were recorded.

Postmortem examinations (parental animals):

SACRIFICE
- Maternal animals

GROSS NECROPSY
- Gross necropsy consisted of internal examinations including the livers, hearts thymus glands and spleen.

HISTOPATHOLOGY / ORGAN WEIGHTS
The heart and thymus weights were recorded.

Postmortem examinations (offspring):

SACRIFICE
- Some of the weanlings were killed at 21 days of age
- These animals were subjected to postmortem examinations

GROSS NECROPSY
- Gross necropsy consisted of internal examinations including the livers, hearts, thymus glands and spleen

HISTOPATHOLOGY / ORGAN WEIGTHS
The heart and thymus weights of the young mice were recoded.

Statistics:

no data

Reproductive indices:

no data available

Offspring viability indices:

no data available

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

not specified

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

not specified

Reproductive performance:

not specified

Details on results (P0)

ORGAN WEIGHTS (PARENTAL ANIMALS)
The high Ca level also caused a significant increase in the absolute and relative heart weights of the mothers.

No further details are given.

Effect levels (P0)

1

Dose descriptor:

LOAEL

Effect level:

2 other: % CaCO3 in diet

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Remarks on result:

other: Generation: young weaned animals (migrated information)

2

Dose descriptor:

LOAEL

Effect level:

2 other: % CaCO3 in diet

Sex:

female

Basis for effect level:

other: The high Ca level also caused a significant increase in the absolute and relative heart weights of the mothers. Based on these changes, the LOAEL for maternal toxicity is established at the dose level of 2.0 % CaCO3.

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Mortality / viability:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

not specified

Histopathological findings:

not specified

Details on results (F1)

VIABILITY AND BODY WEIGHT (OFFSPRING)
On all diets the highest addition of calcium carbonate, which gave a Ca intake of 1.1 % and a Ca:P ratio of approximately 2.3, significantly lowered the number and total weight of young weaned and increased the number and proportion of deaths. There was also some decrease in the number of births.

ORGAN WEIGHTS (OFFSPRING)
Both absolutely and relatively to body-weight the heart weights of the weanlings were significantly increased by Ca and decreased by Fe, whereas thymus weights were decreased by Ca and increased by Fe.
Although the percentage of dry matter in the hearts of the weanlings was significantly lowered by the higher level of Ca, there was a marked increase in the absolute weight of heart dry matter at this level, indicating the presence of a cardiac hypertrophy.

No further details are given.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In all diets, the highest level of CaCO3, 1.1 % Ca contents in food and a Ca:P ratio of approx. 2.3, significantly lowered the number and total weight of young weaned and increased the number and proportion of deaths. There was also some decrease in the number of births. Thus, this dose level of 2 % CaCO3 (1.1 % Ca) is considered as LOAEL for effects on reproductive performance.

The high Ca level also caused a significant increase in the absolute and relative heart weights of the mothers. Based on these changes, the LOAEL for maternal toxicity is established at the dose level of 2.0 % CaCO3. However, daily doses could not be calculated for lack of data on daily food intake. Therefore, determination of a proper NOAEL is not possible.