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Toxicity to birds

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Endpoint:
short-term toxicity to birds
Data waiving:
other justification
Justification for data waiving:
other:
Endpoint:
short-term toxicity to birds: dietary toxicity test
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
As the systemic toxicity of cerium compounds is mainly determined by the extent to which the compound gives rise to bioavailable cerium for uptake in the body, and equally water soluble cerium compounds can be expected to give rise to similar levels of bioavailable cerium under similar conditions, results on systemic toxicity obtained with water soluble cerium compounds can be lumped for hazard assessment purposes. In the case of cerium trinitrate, a study on the toxicity of cerium citrate to birds (Zohravi, 2006) was therefore included in this dossier. The results of this study are however only considered as supporting information because of the mixed exposure conditions during the test and because only an unbound NOEC at relatively low dose was obtained. The full read across justification is attached to IUCLID Section 13.
Reason / purpose for cross-reference:
read-across source
Duration (if not single dose):
4 wk
Dose descriptor:
NOEC
Effect level:
>= 140 mg/kg diet
Conc. / dose based on:
element
Remarks:
Ce
Basis for effect:
other: mortality and growth
Remarks on result:
other: only used as supporting information
Endpoint:
short-term toxicity to birds: dietary toxicity test
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Mixed exposure.
Qualifier:
no guideline followed
Principles of method if other than guideline:
One day old Japanese quails were allotted to a basal diet with several concentrations of REE-citrate (containing Ce, La, and Pr). The experiments lasted four weeks, feed and water were supplied ad libitum. Growth, mortality, and several physiological parameters were monitored throughout the study. Three experiments were conducted. Experiment 1 and 3 were similar concerning the REE-citrate treatments used. Experiment 2 is not discussed because only one low exposure level of REE-citrate was used, not yielding any relevant results.
GLP compliance:
not specified
Dose method:
feed
Analytical monitoring:
yes
Vehicle:
no
Details on preparation and analysis of diet:
The basal diet was formulated according to NRC nutrient requirements of poultry 1994.
The control diet was the basal diet with no additives and the treatment diets were basal diet plus test substance. The test substance with mineral and vitamin supplements was added and mixed with diet at the end of making ration.
Test organisms (species):
Coturnix coturnix japonica
Details on test organisms:
TEST ORGANISM
- Common name: Japanese quails
- Source: institute of animal physiology and nutrition of Munich University
- Age at test initiation (mean and range, SD): one day old
- Weight at test initiation (mean and range, SD): 8.34 g +/- 0.39 g (experiment 1) / 8.10 g +/- 0.49 g (experiment 3)
- Sexes used: no data
Limit test:
no
Total exposure duration (if not single dose):
4 wk
No. of animals per sex per dose and/or stage:
24 (experiment 1), 45 (experiment 3) (no data about sex)
Control animals:
yes, plain diet
Nominal and measured doses / concentrations:
Both experiments: Control + 50, 100, 400, 800 mg/kg (test substance in food)
Details on test conditions:
ACCLIMATION
- Acclimation period: first day after eclosion
- Acclimation conditions (same as test or not): the new born quails were transferred to brooder house and were put in three or four plastic boxes until the next day when experiment started
- Feeding: corn meal
- Health (any disease or mortality observed): no data
- Fasting period before study: no

PEN SIZE AND CONSTRUCTION MATERIALS
- Description: plastic reticular boxes with the size of 60 × 80 cm
- Floor covering: no information
- Caging: group

NO. OF BIRDS PER REPLICATE
- For control: 12 (Exp. 1), 15 (Exp. 3)
- For treated: 12 (Exp. 1), 15 (Exp. 3)

NO. OF REPLICATES PER GROUP
- For control: 2 (Exp. 1), 3 (Exp. 3)
- For treated: 2 (Exp. 1), 3 (Exp. 3)

TEST CONDITIONS (range, mean, SD as applicable)
- Temperature: The temperature in house was set at 38 °C at the first day and was decreased by 2°C every two days during the first week. Then the temperature was weekly decreased by 4°C to reach the room temperature (22 ±2 °C) by the end of the fourth week.
- Relative humidity (%): no data
- Photoperiod: Light was provided for 24 hours per day
- Ventilation: air circulation was provided by ventilators
Details on examinations and observations:
MORTALITY / CLINICAL SIGNS
- Time schedule for examinations: every day the boxes were checked for dead or sick quails
- Remarks: Until the 3rd day of each experiment, the dead quails were replaced with new quails. After the third day the dead quails were removed without replacement and the remaining feed in the feeder was measured.

BODY WEIGHT
- Time schedule for examinations: at initiation, then every week

FOOD CONSUMPTION (if feeding study)
- Time schedule for examinations: every week the amount of feed consumption in each group was calculated by subtraction of the sum of added feed to feeder from the remaining feed in feeder.

WATER CONSUMPTION (if drinking water study): not observed
PATHOLOGY: not observed
ORGAN WEIGHTS: not observed
REGURGITATION: not observed

OTHER:
At the end of each experiment four Japanese quails (two male and two female) were randomly chosen from each box (replicate) and slaughtered by cervical dislocation. Tibia bones, breast and liver were taken from each slaughtered bird. Also a blood sample was taken from each quail during cutting the neck. In blood samples (serum) and tibia bones Calcium, Phosphorus and Magnesium content were measured. The liver and breast samples were taken for measuring the test substance content (with the addition: "if it was necessary").
Duration (if not single dose):
4 wk
Dose descriptor:
NOEC
Effect level:
>= 140 mg/kg diet
Conc. / dose based on:
element
Remarks:
cerium
Basis for effect:
other: mortality and growth
Remarks on result:
other: based on 17.5% Ce present in the REE-citrate mixture at 800 mg/kg diet
Mortality and sub-lethal effects:
MORTALITY
The average percentage of mortality (dead and eliminated animals) during the whole period of experiment was 2.7% in Exp. 1 and 1.3% in Exp. 3. The weak quails which had much lower weight than the average weight of replicate were eliminated. The rate of mortality in Japanese quails was higher during the first week of experiment (3.7%). As there was no special disease during the experiment, the number of dead or eliminated quails significantly dropped to 0.6% (Exp. 1) and 0.5% (Exp. 3) after first week of trial.

CLINICAL SIGNS: no data
ABNORMAL BEHAVIOUR: no data

BODY WEIGHT and WEIGHT GAIN
- Results Exp. 1: Birds receiving REE-citrate had significantly higher body weight than the control group during the first three weeks of Exp. 1. After 4 weeks, the difference was not significant anymore. Similar results were obtained for weight gain. Therefore, for these endpoints, the 28-d NOEC is >= 800 mg REE-citrate/kg food.
- Results Exp. 3: After 28 days, the quails in the highest dose (800 mg/kg) had a slightly but significantly lower body weight than the birds in the control group. However, weight gain was not significantly lower after 4 weeks. Body weight was significantly higher than in the control in the 100 and 400 mg/kg treatments. Here too, no significant differences were observed on weight gain. Therefore, the 28-d NOEC of the first experiment was confirmed.

FOOD CONSUMPTION (if feeding study)
- Results Exp. 1: No significant differences in feed consumption were observed throughout the study.
- Results Exp. 3: No significant differences were observed throughout the study.


WATER CONSUMPTION (if drinking water study): no data
PATHOLOGY: no data
ORGAN WEIGHTS: no data
HISTOPATHOLOGY: no data
Conclusions:
In this study, one-day old Japanese quails were exposed to REE-citrate in which La (5.5%), Ce (17.5%) and Pr (3.28%) were present. The REE-citrate was added to the diet of the quails for 4 weeks. No significant decrease of growth or increase of mortality was observed during the test compared to the control treatment. The NOECs for both mortality and growth were therefore >= 140 mg Ce/kg diet.

Description of key information

Only supporting information was identified (Zohravi, 2006) from a study in which a mixture of rare earth elements (Pr, Ce, La) were added to the food of birds. This information is not sufficient to cover this endpoint. However, because toxicity to birds is an Annex X endpoint and therefore not mandatory for this dossier, no further testing is required.

Key value for chemical safety assessment

Additional information

A single reliable study was identified on the toxicity of cerium to birds. In this study (Zohravi, 2006), one-day old Japanese quails were exposed to REE-citrate in which La (5.5%), Ce (17.5%) and Pr (3.28%) were present. The REE-citrate was added to the diet of the quails for 4 weeks. No significant decrease of growth or increase of mortality was observed during the test compared to the control treatment. The NOECs for both mortality and growth were therefore >= 140 mg Ce/kg diet. However, since the birds were exposed to a mixture of three different rare earth elements, the results of this study are not sufficient to cover this endpoint.

However, being an Annex X endpoint, toxicity to birds is not a mandatory endpoint for this dossier. Therefore, no further testings is required.