Oligo

Repeated dose toxicity: oral

Administrative data

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Principles of method if other than guideline:

A combined chronic oral toxicity (14 rats/sex/dose for 52 weeks) and carcinogenicity study (50 rats/sex/dose for 104 weeks) was performed in Fischer 344/Du Crj rats.

GLP compliance:

not specified

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Mitsubishi-Kasei Foods Corporation

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: refrigerated storeroom
- Stability under test conditions: In an earlier sub-chronic toxicity study, the stability of the test substance was checked after 3, 10, and 18 weeks by gas chromatography.

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Final preparation of a solid: The test substance was mixed with powder feed and tested for uniformity.

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan, Inc.
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 5 weeks
- Housing: 2 animals per cage, polycarbonate cages with hardwood chip bedding
- Diet (e.g. ad libitum): CFR-1 Oriental Yeast Co., Ltd. mixed with test substance, ad libitum, replaced weekly
- Water (e.g. ad libitum): ad libitum

DETAILS OF FOOD AND WATER QUALITY: Diet was tested for contaminants by a third-party laboratory.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-25 degrees C
- Humidity (%): 40-70%
- Air changes (per hr): 12 changes/hr
- Photoperiod (hrs dark / hrs light): 12 hrs dark/ 12 hrs light

Route of administration:

oral: feed

Vehicle:

other: feed

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): every 9 weeks
- Mixing appropriate amounts with (Type of food): CFR-1
- Storage temperature of food: refrigerated

VEHICLE
- Justification for use and choice of vehicle (if other than water): The test substance is a solid with low water solubility.
- Concentration in vehicle: 0, 1, 3, and 5% of daily diet

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The test substance/diet mix was tested for uniformity. The top, middle and bottom of the mix was tested using duplicate samples. The stability of the test substance was checked in an sub-chronic toxicity study at 3, 10, and 18 weeks.

Duration of treatment / exposure:

Chronic oral toxicity: 52 weeks
Carcinogenicity: 104 weeks

Frequency of treatment:

The test substance was mixed with the diet. Test animals had ad libitum access to the test substance/diet mix.

Post exposure period:

None

Dose / conc.:

0 other: % diet

Dose / conc.:

1 other: % diet

Dose / conc.:

3 other: % diet

Dose / conc.:

5 other: % diet

No. of animals per sex per dose:

50 (104 exposure)
14 (52 week exposure)

Control animals:

yes, plain diet

Positive control:

No

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations: Survival, clinical signs, appearance, behaviour

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: Once a week for first 13 weeks, every 4 weeks thereafter.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

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

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Every 3 months, and within 1 week of end of treatment.
- Dose groups that were examined: All doses in the 52 week exposure groups.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Every 3 months for satellite groups, every 6 months for main groups.
- Anaesthetic used for blood collection: No, except for collection prior to sacrifice.
- Animals fasted: Yes, 12 hrs.
- How many animals: All
- Parameters examined: Satellite groups: prothrombin time and activated partial thromboplastin time
Main groups: Erythrocyte count, leukocyte count, differential leukocyte count, platelet counts, hemoglobin, hematocrit, reticulocyte count, prothrombin time, activated partial thromboplastin time, mean corpuscular volume, and mean corpuscular hemoglobin concentration.

CLINICAL CHEMISTRY: Yes, satallite groups only.
- Time schedule for collection of blood: Every 3 months for satellite groups.
- Animals fasted: Yes, 12 hrs
- How many animals: All
- Parameters examined: toatl protein, glucose, triglycerides, total cholesterol, phospholipids, bilirubin, urea nitrogen, creatinine, calcium, inorganic phosphorous, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase, albumin, albumin/globulin ratio, sodium, potassium, and chloride.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, Yes, all animals at termination

ORGAN WEIGHTS: Yes - liver, kidneys, adrenals, testes, ovaries, brain, heart, lungs, and spleen.

HISTOPATHOLOGY: Yes - on 48 tissues and organs in all control and high-dose animals and in animal tissues showing macroscopic changes in the low- and mid-dose groups: brain, pituitary, thyroid, thymus, trachea, lungs, heart, aorta, salivary glands, liver, spleen, adrenals, pancreas, testes, epididymides, prostate gland, seminal vesicle, ovaries, uterus, vagina, skin, tongue, esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, rectum, kidneys, bladder, lymph nodes, mammary glands, muscle, sciatic nerve, femur, sternum, eyes, Harderian glands, spinal cord, nasal cavity, oviducts, auditory sebaceous gland, and extraorbital lacrimal gland, and any other organs and tissues with macroscopic changes.

Statistics:

Numerical data: Bartlett's equial variance test
Data showing homogenous variance: analysis of variance (ANOVA)
Data with a signifcant difference between group: Dunnett's method (if number of animals in each group was the same), Scheffe's method (if number of animals in each group was different)
Data showing heterogenous variance: Kruskal-Wallis H test
Data with a signifcant difference between group: Dunnett-type rank sum test (if number of animals in each group was the same), Scheffe-type rank sum test (if number of animals in each group was different)
Survival ratio: Fischer exact method
Incidences of neoplasms: Armitage's X^2 test

Clinical signs:

no effects observed

Mortality:

mortality observed, non-treatment-related

Description (incidence):

No significant difference was noted in the survival percentages in any treatment group as compared to controls.
Survival at 52 (100%) and 104 weeks (66-76%) was not affected by the treatment.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Males in the high-dose group showed a significant decrease in weight gain in weeks 3, 4, 5, 6, 8, 10, 17, and 49.
During the second year of the study body weight progression was normal.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Food consumption was lower in the high-dose male group, and the female medium- and high-dose groups during the first week.

Food efficiency:

no effects observed

Description (incidence and severity):

Food efficiency was not affected, but an initial reduction in food intake in males and females was observed for a few weeks in the mid- and high-dose groups.

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No toxicologically significant differences between the test groups and the control groups were observed. All differences in values between the test groups and control groups were within historical controls.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

Statistically signifcant differences were noted between the test groups and the control groups, but none of these differences were dose dependent, and are therefore considered incidental.

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

Males in the medium- and high-dose groups showed higher absolute and relative spleen weights at 104 weeks. Males in the high-dose group also showed higher absolute heart weights. There was also an increase in absolute and relative spleen weight, and absolute lung weight in females in the medium-dose group. High spleen weights are common in aged rats of this strain. Incidences of up to 25% are common, as this effect was not seen in animals sacrificed earlier in life, this effect is not considered treatment related.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No statistically significant differences between the test and control groups were seen in surviving animals. In the nonsurviving animals, about 1/2 had large granular lymphocyte leukemia with associated macroscopic observations. As this was also seen in the control group, it is not considered treatment related.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

An increase in extramedullary hematopoiesis was seen in the spleen in some of the 104 week exposure groups including the control group, but these increases were not statistically significant.

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Large granular lymphocyte leukemia was seen in both males and females with increase with increasing dose, but this increase was not statistically significant. An increase in mesothelioma in the abdominal cavity was also not statistically significant, and was within historical controls.

Other effects:

not examined

Details on results:

At termination of the 104 weeks study absolute and relative spleen weights were significantly increased in males at 3% and 5% and in females at 3% (but not in females at 5%). The changes in spleen weight and haematological parameters were most likely caused by the occurrence of large granular lymphocyte (LGL) leukaemia. Aged rats of this strain normally have a high incidence of LGL leukaemia that can be as high as 24% for males and 25% for females. In this experiment, the LGL leukaemia frequencies in the groups receiving 0%, 1%, 3% and 5% of test material were 7/50, 9/50, 11/50 and 12/50 in males and 10/50, 7/50, 14/50 and 13/50 in females, respectively. Thus, LGL leukaemia was a common neoplasm in all groups but was slightly increased without statistical significance at the two top doses. However, when the rats that showed LGL leukaemia were removed from the spleen weight determinations, no differences were seen between treated and control rats. In that case, the spleen weights of the rats treated at concentrations of 0% 1%, 3% or 5% in the diet were 1.3, 1.3, 1.4 and 1.6 g in males 0.6, 0.7, 0.8 and 0.6 g in females, respectively. Consistent with the higher incidence of LGL leukaemia in the high-dose group, there were associated non-neoplastic findings; extramedullary haematopoiesis in the spleen and haematopoietic hyperplasia in the bone marrow was slightly (but not significantly) increased in the high-dose groups.

Relevance of carcinogenic effects / potential:

No statistically significant increase in neoplastic lesions was observed in the test groups.

Key result

Dose descriptor:

NOAEL

Effect level:

5 other: % in diet

Based on:

test mat.

Sex:

male/female

Key result

Dose descriptor:

NOAEL

Effect level:

1 970 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Remarks on result:

other: equivalent to 5% in diet

Key result

Dose descriptor:

NOAEL

Effect level:

2 440 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Remarks on result:

other: equivalent to 5% in diet

Key result

Critical effects observed:

no

Conclusions:

The test substance is not carcinogenic.

Executive summary:

A 2 -year chronic toxicity/carcinogenicity study was performed on male and female rats. Groups of 50 male and 50 females were fed a diet consisting of 0, 1, 3, or 5% of the test substance for 104 weeks. Other groups of 14 male and 14 female rats were fed a diet of the same concentrations for 52 weeks. No statistically significant increase in neoplastic lesions was observed in the test groups.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Chronic toxicity and carcinogenicity of sucrose fatty acid esters in Fischer 344/DuCrj rats

Author:

Takeda, K., and Flood, M.

Year:

2002

Bibliographic source:

Regulatory Toxicology and Pharmacology 35, 157-164.

Reference 2

Reference Type:

review article or handbook

Title:

Sucrose esters of fatty acids, E 473 and sucroglycerides, E 474 based on a request from the Commission related to Sucrose Esters of Fatty Acids (E 473)

Author:

EFSA Scientific Panel

Year:

2004

Bibliographic source:

The EFSA Journal (2004) 106, 1-24

Reference 3

Reference Type:

study report

Title:

Unnamed

Year:

1994

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Principles of method if other than guideline:

A combined chronic oral toxicity (14 rats/sex/dose for 52 weeks) and carcinogenicity study (50 rats/sex/dose for 104 weeks) was performed in Fischer 344/Du Crj rats.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose, UVCB

Molecular formula:

not applicable, substance is UVCB

IUPAC Name:

Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose, UVCB

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Mitsubishi-Kasei Foods Corporation

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: refrigerated store room
- Stability under test conditions: In an earlier sub-chronic toxicity study, the stability of the test substance was checked after 3, 10, and 18 weeks by gas chromatography.

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Final preparation of a solid: The test substance was mixed with powder feed and tested for uniformity.

Test animals

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan, Inc.
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 5 weeks
- Housing: 2 animals per cage, polycarbonate cages with hardwood chip bedding
- Diet (e.g. ad libitum): CFR-1 Oriental Yeast Co., Ltd. mixed with test substance, ad libitum, replaced weekly
- Water (e.g. ad libitum): ad libitum

DETAILS OF FOOD AND WATER QUALITY: Diet was tested for contaminants by a third-party laboratory.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-25 degrees C
- Humidity (%): 40-70%
- Air changes (per hr): 12 changes/hr
- Photoperiod (hrs dark / hrs light): 12 hrs dark/ 12 hrs light

Administration / exposure

Route of administration:

oral: feed

Details on route of administration:

Test animals were fed a diet consisting of 0, 1, 3, or 5% test substance ad libitum.

Vehicle:

other: CRF-1, Oriental Yeast Co., Ltd.

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): every 9 weeks
- Mixing appropriate amounts with (Type of food): CFR-1
- Storage temperature of food: refrigerated

VEHICLE
- Justification for use and choice of vehicle (if other than water): The test substance is a solid with low water solubility.
- Concentration in vehicle: 0, 1, 3, and 5% of daily diet

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The test substance/diet mix was tested for uniformity. The top, middle and bottom of the mix was tested using duplicate samples. The stability of the test substance was checked in an sub-chronic toxicity study at 3, 10, and 18 weeks.

Duration of treatment / exposure:

Chronic oral toxicity: 52 weeks
Carcinogenicity: 104 weeks

Frequency of treatment:

The test substance was mixed with the diet. Test animals had ad libitum access to the test substance/diet mix.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

males and females, 0% in diet

Doses / concentrations 2

Dose / conc.:

394 mg/kg bw/day (nominal)

Remarks:

males, 1% in diet

Doses / concentrations 3

Dose / conc.:

1 160 mg/kg bw/day (nominal)

Remarks:

males, 3% in diet

Doses / concentrations 4

Dose / conc.:

1 970 mg/kg bw/day (nominal)

Remarks:

males 5% in diet

Doses / concentrations 5

Dose / conc.:

480 mg/kg bw/day (nominal)

Remarks:

females, 1% in diet

Doses / concentrations 6

Dose / conc.:

1 440 mg/kg bw/day (nominal)

Remarks:

females, 3% in diet

Doses / concentrations 7

Dose / conc.:

2 440 mg/kg bw/day (nominal)

Remarks:

females, 5% in diet

No. of animals per sex per dose:

Chronic oral toxicity: 14
Carcinogenicity: 50

Control animals:

yes, plain diet

Positive control:

No

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations: Survival, clinical signs, appearance, behaviour

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: Once a week for first 13 weeks, every 4 weeks thereafter.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

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

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Every 3 months, and within 1 week of end of treatment.
- Dose groups that were examined: All doses in the 52 week exposure groups.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Every 3 months for satellite groups, every 6 months for main groups.
- Anaesthetic used for blood collection: No, except for collection prior to sacrifice.
- Animals fasted: Yes, 12 hrs.
- How many animals: All
- Parameters examined: Satellite groups: prothrombin time and activated partial thromboplastin time
Main groups: Erythrocyte count, leukocyte count, differential leukocyte count, platelet counts, hemoglobin, hematocrit, reticulocyte count, prothrombin time, activated partial thromboplastin time, mean corpuscular volume, and mean corpuscular hemoglobin concentration.

CLINICAL CHEMISTRY: Yes, satellite groups only.
- Time schedule for collection of blood: Every 3 months for satellite groups.
- Animals fasted: Yes, 12 hrs
- How many animals: All
- Parameters examined: total protein, glucose, triglycerides, total cholesterol, phospholipids, bilirubin, urea nitrogen, creatinine, calcium, inorganic phosphorous, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase, albumin, albumin/globulin ratio, sodium, potassium, and chloride.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, all animals at termination

ORGAN WEIGHTS: Yes, from liver, kidneys, adrenals, testes, ovaries, brain, heart, lungs, and spleen.

HISTOPATHOLOGY: Yes - on 48 tissues and organs in all control and high-dose animals and in animal tissues showing macroscopic changes in the low- and mid-dose groups:
brain, pituitary, thyroid, thymus, trachea, lungs, heart, aorta, salivary glands, liver, spleen, adrenals, pancreas, testes, epididymides, prostate gland, seminal vesicle, ovaries, uterus, vagina, skin, tongue, esophagus, stomach, duodenum, jejunum, ileum, cecum, colon, rectum, kidneys, bladder, lymph nodes, mammary glands, muscle, sciatic nerve, femur, sternum, eyes, Harderian glands, spinal cord, nasal cavity, oviducts, auditory sebaceous gland, and extraorbital lacrimal gland, and any other organs and tissues with macroscopic changes.

Statistics:

Numerical data: Bartlett's equial variance test
Data showing homogenous variance: analysis of variance (ANOVA)
Data with a signifcant difference between group: Dunnett's method (if number of animals in each group was the same), Scheffe's method (if number of animals in each group was different)
Data showing heterogenous variance: Kruskal-Wallis H test
Data with a signifcant difference between group: Dunnett-type rank sum test (if number of animals in each group was the same), Scheffe-type rank sum test (if number of animals in each group was different)
Survival ratio: Fischer exact method

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Description (incidence):

No significant difference was noted in the survival percentages in any treatment group as compared to controls.
Survival at 52 (100%) and 104 weeks (66-76%) was not affected by the treatment.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Males in the high-dose group showed a significant decrease in weight gain in weeks 3, 4, 5, 6, 8, 10, 17, and 49.
During the second year of the study body weight progression was normal.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Food consumption was lower in the high-dose male group, and the female medium- and high-dose groups during the first week.

Food efficiency:

no effects observed

Description (incidence and severity):

Food efficiency was not affected, but an initial reduction in food intake in males and females was observed for a few weeks in the mid- and high-dose groups.

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No toxicologically significant differences between the test groups and the control groups were observed. All differences in values between the test groups and control groups were within historical controls.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

Statistically signifcant differences were noted between the test groups and the control groups, but none of these differences were dose dependent, and are therefore considered incidental.

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

Males in the medium- and high-dose groups showed higher absolute and relative spleen weights at 104 weeks. Males in the high-dose group also showed higher absolute heart weights. There was also an increase in absolute and relative spleen weight, and absolute lung weight in females in the medium-dose group. High spleen weights are common in aged rats of this strain. Incidences of up to 25% are common, as this effect was not seen in animals sacrificed earlier in life, this effect is not considered treatment related.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No statistically significant differences between the test and control groups were seen in surviving animals. In the nonsurviving animals, about 1/2 had large granular lymphocyte leukemia with associated macroscopic observations. As this was also seen in the control group, it is not considered treatment related.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

An increase in extramedullary hematopoiesis was seen in the spleen in some of the 104 week exposure groups including the control group, but these increases were not statistically significant.

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Large granular lymphocyte leukemia was seen in both males and females with increase with increasing dose, but this increase was not statistically significant. An increase in mesothelioma in the abdominal cavity was also not statistically significant, and was within historical controls.

Details on results:

At termination of the 104 weeks study absolute and relative spleen weights were significantly increased in males at 3% and 5% and in females at 3% (but not in females at 5%). The changes in spleen weight and haematological parameters were most likely caused by the occurrence of large granular lymphocyte (LGL) leukaemia. Aged rats of this strain normally have a high incidence of LGL leukaemia that can be as high as 24% for males and 25% for females. In this experiment, the LGL leukaemia frequencies in the groups receiving 0%, 1%, 3% and 5% of test material were 7/50, 9/50, 11/50 and 12/50 in males and 10/50, 7/50, 14/50 and 13/50 in females, respectively. Thus, LGL leukaemia was a common neoplasm in all groups but was slightly increased without statistical significance at the two top doses.
However, when the rats that showed LGL leukaemia were removed from the spleen weight determinations, no differences were seen between treated and control rats. In that case, the spleen weights of the rats treated at concentrations of 0% 1%, 3% or 5% in the diet were 1.3, 1.3, 1.4 and 1.6 g in males 0.6, 0.7, 0.8 and 0.6 g in females, respectively.
Consistent with the higher incidence of LGL leukaemia in the high-dose group, there were associated non-neoplastic findings; extramedullary haematopoiesis in the spleen and
haematopoietic hyperplasia in the bone marrow was slightly (but not significantly) increased in the high-dose groups.

Effect levels

1

Key result

Dose descriptor:

NOAEL

Effect level:

5 other: % diet

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

food efficiency

gross pathology

haematology

histopathology: neoplastic

histopathology: non-neoplastic

mortality

ophthalmological examination

organ weights and organ / body weight ratios

2

Key result

Dose descriptor:

NOAEL

Effect level:

1 970 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Remarks on result:

other: equivalent to 5% in diet

3

Key result

Dose descriptor:

NOAEL

Effect level:

2 440 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Remarks on result:

other: equivalent to 5% in diet

Target system / organ toxicity

Key result

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

The test substance was not toxic at up to 5% in the diet.

Executive summary:

A 2-year chronic toxicity/carcinogenicity study was performed on male and female rats. Groups of 50 male and 50 females were fed a diet consisting of 0, 1, 3, or 5% of the test substance for 104 weeks. Other groups of 14 male and 14 female rats were fed a diet of the same concentrations for 52 weeks. The test substance was found to be non-toxic at up to 5% in the diet.