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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1981

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material: Zinc sulphate heptahydrate
- Substance type: Pure active substance
- Physical state: Crystal
- Analytical purity: 99.9 %

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Shizuoka Agriculture Cooperative Association for Laboratory Animals
- Age at study initiation: Four wk
- Weight at study initiation: 120-150 g (male); 90-110 g (female)
- Fasting period before study: No data
- Housing: Stainless cages with a wire-meshed bottom
- Diet: Pulverized chows M (Oriental Yeast Co.), ad libitum, mixed with test material
- Water: Ad libitum
- Acclimation period: One wk


ENVIRONMENTAL CONDITIONS
- Temperature: 24±1 °C
- Humidity: 55±5 %
- Air changes (per hr): No data
- Photoperiod: 10 h dark/14 h light cycle


Administration / exposure

Route of administration:
oral: feed
Vehicle:
other: Mixed with basic feed
Details on oral exposure:
PREPARATION OF DOSING DIET:

DIET PREPARATION
- Rate of preparation of diet (frequency): No data
- Mixing appropriate amounts with (Type of food): Pulverized chows M
- Storage temperature of food: No data


Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
No data
Duration of treatment / exposure:
13 wk
Frequency of treatment:
Daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 300, 3000, 30000 ppm
Basis:
nominal in diet
No. of animals per sex per dose:
12
Control animals:
yes, plain diet
Details on study design:
The animals were divided into four groups, each of which included 12 animals of each sex and fed on diets containing Zinc sulphate at
four different concentration levels 0, 300, 3,000 and 30,000 ppm, for 13 wk.
Positive control:
No

Examinations

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily


BODY WEIGHT: Yes
- Time schedule for examinations: Weekly


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes


FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes


WATER CONSUMPTION: Yes
- Time schedule for examinations: Twice a wk


OPHTHALMOSCOPIC EXAMINATION: No data
- Time schedule for examinations: Not applicable
- Dose groups that were examined: Not applicable


HAEMATOLOGY: Yes
- Time schedule for collection of blood: No data
- Anaesthetic used for blood collection: Yes (under light ether anaesthesia)
- Animals fasted: No data
- How many animals: 48
- Parameters checked: Erythrocyte count, hemoglobin, leukocyte count, differential count of leukocyte


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: No data
- Animals fasted: No data
- How many animals: 48
- Parameters checked: Total plasma protein, alkaline phosphatase, glucose, urea nitrogen, SGOT, SGPT, cholesterol and calcium.


Sacrifice and pathology:
GROSS PATHOLOGY: Yes
After necropsy at the termination of the study the following organs were weighed: Brain, pituitary, thyroid, heart, thymus, liver, kidney, spleen, adrenals, gonads (testes or ovaries), and muscles (triceps surae).

HISTOPATHOLOGY: Yes (see table)
- For histopathology following organs and tissues were collected: Brain, pituitary, thyroid, heart, thymus, liver, kidney, spleen, adrenals, gonads (testes or ovaries), and muscles (triceps surae), submaxillary glands, lungs, mesenteric lymph nodes, pancreas, stomach, small and large intestine, accessory genital organs, bone and bone marrow (sternum and femur), and lesions of gross abnormalities
- 3 or 4 µm paraffin sections from the specimens were stained with hematoxylineosin, periodic acid Schiff's reaction and azan for microscopic observations.
Other examinations:
None
Statistics:
Student's t-test was used to estimate the statistical differences between controls and treated groups

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Food efficiency:
effects observed, treatment-related
Water consumption and compound intake (if drinking water study):
effects observed, treatment-related
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
not specified
Details on results:
CLINICAL SIGNS AND MORTALITY:
- At 30,000 ppm: Showed symptom of discarding the diet from the food jar by picking it out with their fore-limbs. This symptom began a week
after commencement of the experiment and persisted throughout the study. No moribund animals of either sex were found.
- At ≤ 3,000 ppm: No remarkable signs in either sex. Two females, one of the control and one of the 3,000 ppm group, were killed in extremis due to suppurative pyelitis during the study.

BODY WEIGHT AND WEIGHT GAIN:
- At 30,000 ppm: Depressed weight gain and dwarfism. Weight gain of females in this group was slightly depressed during the study with significant
differences to control animals in the 1st to 5th wk of the study.
- At ≤ 3,000 ppm: Statistically not significant values when compared to control
FOOD & WATER CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- At 30,000 ppm: Food intake of males decreased after the third wk of the study. A similar reduction was seen in females of this group during the 1st to 6th wk but then disappeared. A slightly lower value of average food and water intake was reported only in males.
- At ≤ 3,000 ppm: Statistically not significant values when compared to control

FOOD EFFICIENCY:
There were some fluctuations in food efficiency in each group.
- At 30,000 ppm: Slight reduction in overall average value.
- At ≤ 3,000 ppm: Statistically not significant values when compared to control


HAEMATOLOGY:
-At 30,000 ppm: A moderate reduction in leukocyte count was shown in both sexes. Males showed a slight decrease in hematocrit and hemoglobin concentration.
- At 3,000 ppm: No remarkable changes in animals but there was a slight increment of hemoglobin concentration in females

CLINICAL CHEMISTRY:
Significant reductions or reductive tendencies were seen in rats in the following parameters: SGOT and SGPT in all male groups, total protein, cholesterol and calcium levels in males in the 30,000 ppm group and calcium level in females in both the 3,000 and 30,000 ppm groups.


ORGAN WEIGHTS:
-At 30,000 ppm: A slight or moderate decrease in absolute and relative weights was seen in the liver and kidney among males
- Significant fluctuations of absolute or relative organ weights were seen in various organs from chemically treated groups of both species, no clear relationship with the treatment could be shown.
- At ≤ 3,000 ppm: Statistically not significant values when compared to control

GROSS PATHOLOGY
No remarkable lesions were attributable to the treatment.

HISTOPATHOLOGY: NON-NEOPLASTIC
- At 30,000 ppm: Pancreatic lesions as well as degeneration and necrosis of the acinar cells, clarification of centroacinar cells and interstitial fibrosis. No other lesions attributable to the treatment.
- No histopathological abnormalities were observed in the bone or male genital organs which had elsewhere been reported to have sustained toxic changes due to an overdose of Zinc.




Effect levels

Dose descriptor:
NOEL
Effect level:
3 000 ppm
Sex:
male/female
Basis for effect level:
other: No remarkable clinical signs in either sex at ≤ 3000 ppm diet admix, approximately equivalent to 234 mg/kg/day (~53.5 mg Zn2+/kg bw/day) (male) and 243 mg/kg/day (female)

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

See the attached pdf for the following figure and tables:

Fig. 2. Group mean body weights in rats

Table 2. Food, chemical, water intake and food efficiency in rats

Table 4. Hematology-mean values in rats.

Table 6. Blood biochemistry--mean values in rats

Table 8. Absolute and relative organ weights in rats

Applicant's summary and conclusion

Conclusions:
Under the test conditions, NOEL of the test material in rats was determined to be 3,000 ppm (approximately equivalent to 234 mg/kg/day in male rats and 243 mg/kg/day in female rats)
Executive summary:

This study was conducted to evaluate the subchronic toxicity (13 wk) of the test material in Wister rats. The study followed was equivalent or similar to OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents).

Rats of both sexes were fed a diet containing the test material at 0, 300, 3,000 and 30,000 ppm for 13 wk. The clinical signs of the animals, body weight, food, chemical and water intake, food efficiency, hematological, biochemical examination, necropsy and organ weight and histopathological examination were performed.

Animals in the 30,000 ppm group showed retarded growth along with low food intake, abnormal values in a few hematological parameters and regressive changes of the pancreatic exocrine gland. There were no remarkable clinical signs in either sex in groups 3,000 ppm.

Under the test conditions, NOEL of the test material in rats was determined to be 3000 ppm (approximately equivalent to 234 mg/kg/day in male rats and 243 mg/kg/day in female rats).