Propargite

Toxicity to reproduction

Administrative data

Endpoint:

two-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11th April 1998 to 16th June 1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPP 83-4 (Reproduction and Fertility Effects)

Deviations:

no

Remarks:

There were a number of protocol deviations but none were expected to affect the results of the study

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Propargite

EC Number:

219-006-1

EC Name:

Propargite

Cas Number:

2312-35-8

Molecular formula:

C19H26O4S

IUPAC Name:

propargite

Test material form:

liquid

Test animals

Species:

rat

Strain:

other: Crl: CD BR

Details on species / strain selection:

The rat is sensitive to a number of agents that interfere with reproduction and is frequently used in safety evaluation studies as a representative of a rodent species.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Portage, Michigan, USA
- Age at study initiation: (P) 6 wks
- Weight at study initiation: (P) 123-236 g. The weight variation of the animals of each sex selected for the F0 generation of the study were within ±2 standard deviations of the mean body weight for each sex, and group mean body weights for each sex were not statistically different at the 5 % level.
- Housing: Animals were housed individually in suspended, stainless steel, screen-bottom cages except during breeding periods, when each female was housed with a male in a double-sized, stainless steel cage. Pregnant rats (beginning at approximately Day 15 of gestation), rats with pups, and females that did not show evidence of positive mating were housed in polycarbonate cages. A bedding material consisting of heat-treated hardwood chips covered the bottom of the polycarbonate cages and was changed at least once weekly.
- Diet: Certified Rodent Chow® #5002 ad libitum
- Water: ad libitum from an automatic system or in water bottles (during the last week of gestation and during lactation).
- Acclimation period: (P) two weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 72 ± 3 ºF
- Humidity: 50 ± 20 %
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES
- From: (P) 28 March 1988
- To: (P) Week of 07 November 1988

Administration / exposure

Route of administration:

oral: feed

Vehicle:

corn oil

Details on exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): Diets were prepared weekly.
- Mixing appropriate amounts with basal diet: Dietary concentrations were based on the test material after correction for purity. Each dose level was prepared independently in order of increasing concentration. A specified amount of basal diet was weighed into a labelled Hobart® mixing bowl, from which approximately 1 kg was removed and placed in an N-50 mixing bowl. The required amount of test material was weighed in a glass beaker, and a specified amount of corn oil was weighed and added to the test material. This test material and corn oil mixture was stirred, transferred to the N-50 mixing bowl, then thoroughly mixed; this premix was transferred to the Hobart mixing bowl. The contents of the Hobart mixing bowl were then thoroughly mixed. Control diets were prepared using the maximum amount of corn oil that was used to prepare the test diets.
- Storage temperature of food: Diets were stored refrigerated in covered containers until dispensed into food jars.

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: Maximum of 21 days.
- Proof of pregnancy: Vaginal plug / sperm in vaginal smear referred to as day 0 of gestation. The date of mating (i.e., date that positive sperm or vaginal plug was observed) and male number were recorded. Vaginal smears were taken daily during cohabitation, and the presence of a copulatory plug or sperm in the vaginal smear was considered evidence of positive mating.
- After successful mating each pregnant female was caged (how): Once mating had occurred, the males and females were separated and females housed individually. On approximately Day 15 of gestation, the mated female was placed in a plastic, solid-bottom nesting cage. Females that showed no evidence of mating were placed in nesting boxes after the mating period.
- Assignment of animals for breeding: Breeding was initiated by selecting 1 male and 1 female at random from the same treated group and placing each pair of animals in a separate, double-sized, screen-bottom cage. The first female in the randomization sequence was placed with the first male in the randomization sequence from the same group. The next female was placed with the next male, and this sequence was repeated until all available animals were paired. Sibling matings were avoided.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples for dose analyses were taken directly from the mixing bowl during diet preparation.
Assays for the test material in the basal diet were done by the testing facility using an analytical method developed and validated in house. Homogeneity was determined for all dietary concentrations. Samples taken from the top, bottom and two opposing sides of the mix were assayed in duplicate for test material content.
To evaluate the stability of the test material in basal diets, four sets of samples were taken from the lowest and highest test material concentrations used for the study. One set was analysed after being stored 7 days in the animal room, then 7 days in a freezer; and one set was analysed after being stored refrigerated for 1 day, 8 days in the animal room, then 27 days in a freezer.
The remaining sets were stored in a freezer; one set was analysed after 18 days and the other set was analysed after 57 days.
All diets for the first 4 weeks of the study were assayed. Each week thereafter, one test material concentration was selected sequentially for analysis. These samples and a sample of the control diet were analysed as a group approximately every 4 weeks. For Weeks 24 and 51, all dose levels were also analysed. All samples were stored in a freezer until analysed.

ANALYTICAL METHOD
The samples are extracted with hexane by shaking for 30 minutes. The extract is centrifuged and cleaned up on a florisil column. The final extract is concentrated by evaporating under nitrogen, transferred into chloroform, and injected on a GC-FID.

- Precision, Sensitivity, Accuracy
The limit of detection for this method was established at 20 ppm. When validated, thirty-two feed samples were spiked and assayed at two separate levels (2000 and 100 ppm). The mean percent recovery for these samples was 95 % with a coefficient of variation of 0.041.

- Interference
A temperature program is recommended because of the presence of late eluting peaks

- Procedure
Extraction: Weigh 10.0 grams of feed directly into a glass stoppered 250 mL Erlenmeyer flask. Add 50 mL of hexane, secure stopper, and shake on a wrist-action shaker for 30 minutes. Centrifuge hexane extract for 10 minutes at 2000 rpm.
Florisil Chromatography: Prepare a "wet packed" florisil column by adding 10 g of activated florisil to a 1.2 x 27 cm glass chromatographic column which is filled with hexane. After the column has settled cap the column with 5.0 grams of Na2SO4 and drain the excess hexane to the top of the Na2SO4 layer. Place an aliquot of hexane extract on the florisil column. Extract the flask with two additional 25 mL rinses and place on the column. Drain to the top of the Na2SO4 layer and discard effluents. Rinse the florisil column with an additional 50 mL of hexane and discard. Elute the test material from the column with 100 mL of 5 % acetone in hexane and collect in a 250 mL boiling flask.
Concentration and GC Analysis: Evaporate the 5 % acetone: hexane to dryness using a nitrogen stream. Extract the dry flask with chloroform rinses, transfer quantitatively to a 10 or 20 mL volumetric flask and dilute to volume. Inject a 2 µL aliquot into a GC-FID under the following conditions:
Column: 3 %, SP 2100 6’x 4 mm ID
Temperature: Injector: 300 °C; Column: 235 °C 8 min, 32 °C/min, 280 °C 8 min; Detector: 300 °C
Carrier: He at 60 mL/min

Due to the nature of the test material, inconsistent responses upon injection were observed. To deter from this the glass wool was removed from the front of the GC column.

- Calculation
C x (V / F) x D = µg/g, ppm test material
where:

C = concentration of extract from standard curve (µg/mL)
V = final volume (mL)
F = weight of feed (g)
D =dilution factor, if any

RESULTS
Mean values for method validation assay results ranged from 88 to 104 % of the theoretical levels. These results indicate that the method was suitable for the range of dietary concentrations in this study.
The results of homogeneity assays at 80, 400 and 800 ppm of diets mixed before initiation of treatment ranged from 104 to 106 %, 99 to 102 % and 97 to 104 % of the theoretical levels, respectively. These results indicate that the mixing procedure produced homogeneous mixtures.
The results for stability analyses of diets mixed at the low (80 ppm) and high (800 ppm) dose levels ranged from 95 to 102 % of the theoretical levels under various storage conditions. Stability assay results (duplicate assay means) for the 80- and 800-ppm dose levels, were as follows: diets stored for 7 days under animal room conditions, followed by 7 days in a freezer were 96 and 95 %, respectively, of the theoretical levels; diets stored refrigerated for 1 day, followed by 8 days under animal room conditions then 27 days in a freezer were 99 and 102 %, respectively, of the theoretical levels; diets stored in a freezer for 18 days were 99 and 98 %, respectively, of the theoretical levels; and diets stored in a freezer for 57 days were 99 and 99 %, respectively, of the theoretical levels.
Control diets were all below the limit of detection of the assay. The results indicate that the test material was stable when mixed in the basal diet. Overall mean dose results for the study were 96, 95, and 96 % of the theoretical levels of 80, 400, and 800 ppm, respectively.
The results of the dose verification analyses from Weeks 1 through 62 indicate that the diets were prepared at the proper levels, except Week 24, when assay results indicated that diets for Groups 3 (400 ppm) and 4 (800 ppm) were inadvertently switched. The in-life data indicate that the inadvertent switch of diets for Week 24 appeared to be insignificant, because decreased body weight, body weight gain, and food consumption were observed in the 400- and 800-ppm groups, and there were no adverse reproductive effects at any dose level.

Duration of treatment / exposure:

Over two generations

Frequency of treatment:

Continuous in the diet

Details on study schedule:

DOSE ADMINISTRATION
The F0 males and females received the test material in the diet continuously from initiation of treatment (11 April 1988) for 10 weeks before mating; throughout mating, gestation, and lactation for the F1a and F1b litters; and until necropsy on 07 to 09 November 1988.
The F1b males and females were exposed to the test material post-weaning for at least 10 weeks before mating; throughout mating, gestation, and lactation for F2a and F2b litters; and until necropsy on 13 to 16 June 1989.

BREEDING
Breeding of the F0 adults for F1a litters was initiated on 20 June 1988, after test diets had been fed to the animals for 10 weeks. After weaning of the F1a litters, the F0 adults were rested for at least 2 weeks. Breeding to produce the F1b litters was initiated on 05 September 1988.
Breeding of the F1b adults for F2a litters was initiated on 24 January 1989, after test diets had been fed to the animals for at least 10 weeks. After weaning of the F2a litters, the F1b adults were rested for at least 2 weeks. Breeding to produce the F2b litters was initiated on 11 April 1989. Breeding pairs used to produce the F1a and F2a litters were not the same pairs used to produce the F1b and F2b litters, respectively.
On Day 21 of F1b lactation, 1 male and 1 female pup were selected at random from each litter to continue as F1b generation adult animals. For litters without a male or female pup, 1 weanling was selected at random from the pups of the available sex. When sufficient pups or litters were not available, male and female pups were selected at random from the remaining litters to provide 25 male and 25 female weanlings/group.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

80 ppm (nominal)

Doses / concentrations 2

Dose / conc.:

400 ppm (nominal)

Doses / concentrations 3

Dose / conc.:

800 ppm (nominal)

No. of animals per sex per dose:

Twenty-five animals per sex per dose

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: Dose levels were selected based on results from a chronic study in rats in which 800 ppm was shown to be the maximum­tolerated dose, and minimal effects were seen at 100 ppm and based on results from previous studies in which effects had been seen at 2000 ppm but not at 900 ppm.
- Rationale for animal assignment: Animals were assigned to the F0 generation of the study using a computer­ generated randomization.

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Twice daily (mortality and moribundity); once daily (signs of toxicity). During gestation, females were observed closely for signs of abortion, excessive bleeding, premature delivery or difficult and prolonged parturition.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: A detailed physical examination was given on the first day of treatment, weekly thereafter and on the day of necropsy. Females were also examined weekly after the lactation phase.

BODY WEIGHT: Yes
- Time schedule for examinations: Males were weighed on the first day of treatment, weekly thereafter and on the day of necropsy. Females were weighed on the first day of treatment, weekly during premating, on presumed days 0, 7, 14 and 20 of gestation, on days 0, 4, 7, 14 and 21 of lactation and on the day of necropsy.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Time schedule: Individual food consumption data were recorded weekly during premating phase of the F0 and F1b generations (F1a and F2a litters).

WATER CONSUMPTION: No

Sperm parameters (parental animals):

Parameters examined in all adult males: Weight of testes, epididymides, coagulation gland and seminal vesicles

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 8 pups/litter (4/sex/litter as nearly as possible); excess pups were killed and discarded. Any pup with an external abnormality was culled. Culled pups were sacrificed using T-61® euthanasia solution.

PARAMETERS EXAMINED
- Birth (Day 0 of Lactation): As soon as possible after birth, the sex of each pup was determined and the litter size (total number of pups born live or found dead) was recorded. Each live pup was examined for external abnormalities and weighed.
- Day 4: The sex of each pup was determined, and the litter size (number of live pups) was recorded. The pups were examined for external abnormalities and weighed.
- Days 7, 14 and 21: Litter size (number of live pups) was recorded. Live pups were examined for external abnormalities and were weighed individually.

GROSS EXAMINATION OF DEAD PUPS:
Whenever possible, any offspring found dead were examined externally and internally.
- Birth (Day 0 of Lactation): Dead pups were examined macroscopically for cervical, thoracic, and abdominal visceral abnormalities and possible cause of death, then discarded.
- Day 4: Culled pups were examined for cervical, thoracic, or abdominal visceral abnormalities then discarded.

ASSESSMENT OF DEVELOPMENTAL NEUROTOXICITY: No

ASSESSMENT OF DEVELOPMENTAL IMMUNOTOXICITY: No

Postmortem examinations (parental animals):

SACRIFICE
A necropsy was done to the fullest extent possible on all adult animals that died or were sacrificed in a moribund condition.
After the F1b and F2b pups were weaned, the respective parental (F0 and F1b) adult males and females were anesthetized with methoxyflurane, weighed, exsanguinated, and necropsied.

GROSS NECROPSY
The necropsy included a macroscopic examination of the external surface of the body, all orifices, the cranial cavity, the external surfaces of the brain and spinal cord, the nasal cavity and paranasal sinuses and the thoracic, abdominal, and pelvic cavities and viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS
At the scheduled necropsy, the following (when present), or representative samples thereof, were preserved in 10 % phosphate-buffered formalin: Cervix, coagulation gland, gross lesions, epididymides, ovaries, prostate, pituitary, seminal vesicles, testes, uterus and vagina.
These were embedded in paraffin, sectioned, stained with haematoxylin and eosin, and examined microscopically from all F0 and F1b adults in the control and high-dose groups.

Postmortem examinations (offspring):

SACRIFICE
On Day 21 of F1a lactation, all F1a pups were euthanatized by carbon dioxide asphyxiation and discarded. On Day 21 of F1b lactation, all F1b pups not selected as future parents were euthanatized by carbon dioxide asphyxiation and discarded. On Day 21 of F2a and F2b lactation, or as soon as possible thereafter, all F2a and F2b pups were euthanatized by carbon dioxide asphyxiation and discarded.

GROSS NECROPSY
Whenever possible, any offspring found dead were examined externally and internally.

Statistics:

Levene's test was done to test for variance homogeneity. In the case of heterogeneity of variance at p≤0.05, rank transformation was used to stabilize the variance.
Analysis of variance (ANOVA) was done on the homogeneous or transformed data. If the ANOVA was significant, Dunnett's t-test, Student's t-test or Games and Howell Modified Tukey-Kramer test was used for pairwise comparisons between groups.
Standard one-way ANOVA was used to analyze body weight, body weight gain, food consumption, litter data, days to mate, and length of gestation. Reproduction indices were analyzed by the Cochran-Armitage test for trend and departure and by a Fisher-Irwin exact test.
Group comparisons were found to be statistically significant at the 5.0 and 1.0 % two-tailed probability levels.
As appropriate, for percentages calculated to analyze litter data or mean pup weight data, values were first derived within the litter, and the group mean values were derived as a mean of individual litter percentages.

Reproductive indices:

Mating index = (Number of females mated / Number of females placed with males) x 100
Female fertility index = (Number of females pregnant / Number of females mated) x 100
Male fertility index = (Number of males shown to be fertile / Number of males placed with females) x 100
Gestation index = (Number of live litters born/ Number of pregnant females) x 100

Offspring viability indices:

Viability index = (Number of pups surviving to Day 4 / Number of pups born alive) x 100
Weaning index = (Number of pups surviving to Day 21/ Number of pups alive at Day 4 post-culling) x 100
Sex ratio (Days 0 and 21) = (Number of live male pups / Total number of live pups) x 100

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No test material-related clinical observations were noted.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

There were no treatment related effects on survival.
In the F0 generation (F1a Litter), 1 male at the 80-ppm level was sacrificed in a moribund condition during Week 17 after showing signs of genital problems (bleeding from the penis) and body weight loss. In the F0 generation (F1b Litter), 1 female in the control group was sacrificed on Day 16 of gestation after showing evidence of abortion; 1 female at the 80-ppm level was found dead 6 days post-copulation; and 1 female at the 80-ppm level was sacrificed in a moribund condition on Day 1 of lactation after a prolonged parturition and subsequent loss of pups.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

BODY WEIGHT
In the F0 generation (F1a Litter), mean body weights were significantly (approximately 5 %) lower for the 400-ppm males at Weeks 3 through 8 and 10 of the premating phase and were significantly (9 to 18 %) lower for the 800-ppm males beginning at Week 1 of the premating phase and continuing throughout the postmating phase. The mean body weights were significantly (approximately 5 %) lower for the 400-ppm females for Weeks 7 through 10 of the premating phase and for Days 0 and 7 of gestation and were significantly (approximately 5 to 15 %) lower for the 800-ppm females beginning at Week 1 and continuing throughout the premating, gestation, and lactation phases.
In the F0 generation (F1b Litter), mean body weights were significantly (6 to 7 %) lower for the 400-ppm males throughout most of the postmating phase and were significantly (17 to 19 %) lower for the 800-ppm males throughout the entire premating and postmating phases. The mean body weights were significantly (approximately 7 %) lower for the 400-ppm females throughout the premating and gestation phases and on Days 0 and 4 of lactation. The mean body weights were significantly (7 to 18 %) lower for the 800-ppm females throughout the premating, gestation, and lactation phases.

BODY WEIGHT CHANGES
In the F0 generation (F1a Litter), the mean cumulative body weight gains for the 400- and 800-ppm males were significantly (7 to 10 % and 27 to 41%, respectively) lower throughout most of the premating and postmating phases. Although the mean cumulative body weight gains were significantly (17 %) higher for the 400-ppm females during Weeks 0 to 1 of the premating phase, they were significantly (approximately 10 %) lower for these animals during Weeks 7, 8 and 10 of premating. Cumulative body weight gains were significantly (20 to 29 %) lower for the 800-ppm females throughout the entire premating phase. The overall mean cumulative body weight gains during lactation for the 400- and 800- ppm females were significantly higher than those of the controls.
In the F0 generation (F1b Litter), the mean cumulative body weight gains were significantly lower for the 400-ppm males throughout most of the postmating phase and lower for the 800-ppm males during Week 1 of the premating phase and throughout most of the postmating phase. The mean cumulative body weight gains were significantly (33 %) lower for the 400-ppm females for Days 7 to 14 of gestation. The overall mean cumulative body weight gains during lactation for the 400- and 800-ppm females were significantly higher than those of the controls.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

In the F0 generation, mean food consumptions were significantly (5 to 8 %) lower for the 400-ppm males during Weeks 0 to 1, 4 to 5 and 8 to 9 of the premating phase and were significantly (8 to 21 %) lower for the 800-ppm males throughout the entire premating phase. The mean food consumptions were significantly (approximately 7 %) lower for the 400-ppm females during Weeks 6 to 7 and were significantly (11 to 21 %) lower for the 800-ppm females throughout the entire premating phase.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test material-related microscopic changes. All microscopic findings were considered to be incidental and unrelated to the dietary intake of the test material.

Histopathological findings: neoplastic:

not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

effects observed, non-treatment-related

Description (incidence and severity):

- Males: There were no adverse significant differences for male fertility indices during breeding for the F1a and F1b litters.
- Females: There were no adverse significant differences observed for mating, female fertility, or gestation indices or mean days to mate for the F1a and F1b litters. There was a statistically significant decrease in the mean duration of F1a gestation for the 400- and 800-ppm females; however, this difference was very slight and is not considered to be biologically significant.

Effect levels (P0)

1

Key result

Dose descriptor:

NOEL

Remarks:

Systemic effects

Effect level:

80 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

2

Key result

Dose descriptor:

NOEL

Remarks:

Reproductive performance

Effect level:

> 800 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive performance

Target system / organ toxicity (P0)

Key result

Critical effects observed:

no

Results: P1 (second parental generation)

General toxicity (P1)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No test material-related clinical observations were noted.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

There were no treatment related effects on survival.
No deaths occurred during the F1b generation (F2a Litter) phase of the study. In the F1b generation (F2b Litter), 1 male at the 800-ppm level was sacrificed in a moribund condition during Week 6 after showing signs of paralysis in the hind limbs; 1 female at the 80-ppm level was sacrificed in a moribund condition 7 days post-copulation after a movable mass became ulcerated; and 1 female at the 400-ppm level was sacrificed in a moribund condition on Day 2 of lactation after showing signs of staggered gait, red stains at the eyes, mouth, forelimbs, and genital area and emaciation (the entire litter was stillborn).

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

BODY WEIGHT
In the F1b generation (F2a Litter), mean body weights were significantly (5 to 9 %) lower for the 400-ppm males throughout most of the premating phase and continuing throughout the postmating phase and were significantly (26 to 29 %) lower for the 800-ppm males throughout the entire premating and postmating phases. The mean body weights were significantly (approximately 5 to 10 %) lower for the 400-ppm females beginning Week 1 and continuing throughout the premating and gestation phases and on Days 0, 4, 7, and 14 of lactation. The mean body weights were significantly (18 to 22 %) lower for the 800-ppm females beginning at Week 0 and continuing throughout the premating, gestation, and lactation phases.
In the F1b generation (F2b Litter), mean body weights for the 400- and 800-ppm males were significantly (8 to 10 % and 26 to 27 %, respectively) lower throughout the entire premating and postmating phases. The mean body weights were significantly (5 to 10 % and 15 to 22 %) lower for the 400- and 800-ppm females, respectively, throughout the premating, gestation, and lactation phases.

BODY WEIGHT CHANGES
In the F1b generation (F2a Litter), the mean cumulative body weight gains were significantly (10 to 12 %) lower for the 400-ppm males throughout most of the premating phase, during mating and Weeks 11, 12, and 16 postmating and were significantly (25 to 29 %) lower for the 800-ppm males throughout the entire premating and postmating phases. The mean cumulative body weight gains were significantly (18 to 24 % and 19 to 22 %) lower for the 400- and 800-ppm females throughout the entire premating phase. The mean cumulative body weight gains for the 800-ppm females were significantly (approximately 18 %) lower throughout most of gestation. The overall mean cumulative body weight gains during lactation for the 400-ppm females were significantly higher than those of the controls.
In the F1b generation (F2b Litter), the mean cumulative body weight gains were significantly (21 to 24 % and 27 to 34 %) lower for the 400- and 800-ppm males, respectively, during the last 2 weeks of the postmating phase. Although the mean cumulative body weight gains for the 80-ppm females were significantly higher during the 2-week period before mating, no significant changes were seen during gestation or lactation for these animals. The mean cumulative body weight gains were significantly (28 %) lower for the 400-ppm females for Days 0 to 7 of gestation and significantly (16 to 36 %) lower for the 800-ppm females throughout most of gestation. The overall mean cumulative body weight gains during lactation for the 400- and 800-ppm females were significantly higher than those of the controls.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

In the F1b generation, mean food consumptions were significantly (5 to 8 %) higher for the 80-ppm males starting at Week 0 and continuing through Week 6 of premating; however, these differences were not considered biologically meaningful because there were no significant differences in body weight or body weight change data for this time period. The mean food consumptions were significantly (6 to 8 %) lower for the 400-ppm males starting at Week 2 and continuing throughout the premating phase and significantly (19 to 25 %) lower for the 800-ppm males throughout the entire premating phase. The mean food consumptions for the 400-ppm females were significantly (9 to 19 %) lower throughout most of the premating phase and significantly (17 to 31 %) lower for the 800-ppm females throughout the entire premating phase.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test material-related macroscopic changes. All macroscopic findings were considered to be incidental and unrelated to the dietary intake of the test material.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test material-related microscopic changes. All microscopic findings were considered to be incidental and unrelated to the dietary intake of the test material.

Histopathological findings: neoplastic:

not examined

Reproductive function / performance (P1)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Description (incidence and severity):

- Males: There were no adverse significant differences for male fertility indices during breeding for the F2a and F2b litters.
- Females: There were no adverse significant differences observed for mating, female fertility, or gestation indices or mean days to mate for the F2a and F2b litters.

Effect levels (P1)

1

Key result

Dose descriptor:

NOEL

Remarks:

Systemic effects

Effect level:

80 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

2

Key result

Dose descriptor:

NOEL

Remarks:

Reproductive performance

Effect level:

> 800 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive performance

Target system / organ toxicity (P1)

Key result

Critical effects observed:

no

Results: F1 generation

General toxicity (F1)

Clinical signs:

not examined

Mortality / viability:

not specified

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Pup weights were significantly lower for the F1a litters at the 400-ppm dose level for Lactation Days 7, 14, and 21 and at the 800-ppm dose level for Lactation Days 0, 4, 7, 14, and 21 and significantly lower for the F1b litter at the 400-ppm dose level for Lactation Days 7, 14, and 21 and at the 800-ppm dose level for Lactation Days 4, 7, 14, and 21.
At Lactation Day 21, F1a and F1b pup weights in the 400-ppm group were 12 and 8 % lower, respectively, than those of the controls; pup weights in the 800-ppm group were 37 and 36 % lower, respectively, than those of the controls.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Description (incidence and severity):

Although not specifically examined, the F1b animals were bred to produce the F2a and F2b litters with no effects being seen on reproduction parameters.

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no test material-related findings noted during the necropsy of culled pups or pups found dead.

Histopathological findings:

not examined

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not examined

Details on results (F1)

In general, there were no adverse significant differences observed for the number of pups per litter or sex ratio for the F1a and F1b litters.

Effect levels (F1)

Key result

Dose descriptor:

NOEL

Generation:

other: F1a and F1b

Effect level:

80 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Target system / organ toxicity (F1)

Key result

Critical effects observed:

no

Results: F2 generation

General toxicity (F2)

Clinical signs:

not examined

Mortality / viability:

not specified

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Pup weights were significantly lower for the F2a litter at the 400-ppm dose level for Lactation Days 14 and 21 and at the 800-ppm dose level for Lactation Days 0, 4, 7, 14 and 21; and significantly lower for the F2b litter at the 400-ppm dose level for Lactation Days 7, 14, and 21 and at the 800-ppm dose level for Lactation Days 0, 4, 7, 14, and 21.
At Lactation Day 21, F2a and F2b pup weights in the 400-ppm group were 11 and 14 % lower, respectively, than those of the controls; pup weights in the 800-ppm group were 43 and 38 % lower, respectively, than those of the controls.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no test material-related findings noted during the necropsy of culled pups or pups found dead.

Histopathological findings:

not examined

Developmental neurotoxicity (F2)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F2)

Developmental immunotoxicity:

not examined

Details on results (F2)

In general, there were no adverse significant differences observed for the number of pups per litter or sex ratio for the F2a and F2b litters.

Effect levels (F2)

Key result

Dose descriptor:

NOEL

Generation:

other: F2a and F2b

Effect level:

80 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Target system / organ toxicity (F2)

Key result

Critical effects observed:

no

Overall reproductive toxicity

Key result

Reproductive effects observed:

no

Applicant's summary and conclusion

Conclusions:

When the test material was administered to rats continuously in the diet through 2 generations (2 litters per generation) at concentrations up to and including 800 ppm, the only treatment-related effects were decreased body weights, body weight gains and food consumptions in males and females at 400 and 800 ppm of the F0 and F1b generations. Based on these results, the no-observable-effect level was 80 ppm for systemic effects and greater than 800 ppm for male and female reproduction performance. These values are equivalent to 4 and 40 mg/kg bw/day, respectively.

Executive summary:

The purpose of this study was to assess the effects of the test material on male and female gonadal function, mating behaviour, fertility, gestation, parturition and lactation and the growth and development of offspring from two consecutive generations of rats (2 litters per generation) that were continuously exposed to the test material. The F0 generation had the F1a and F1b litter; the F1b generation had the F2a and F2b litters.

Groups of 25 male and 25 female immature Crl:CD®BR albino rats (F0 animals) were fed diets that contained 0, 80, 400 or 800 ppm for 10 weeks premating and throughout mating, gestation, lactation and weaning of the F1a pups. After weaning of the F1a litters, the F1a pups were sacrificed and discarded, and the F0 animals were then re-mated to produce F1b litters. After weaning, the F1b animals were assigned at random to 4 groups (25/sex/group) and the F0 adults were sacrificed and necropsied. The selected F1b animals were fed diets that contained 0, 80, 400 or 800 ppm for at least 10 weeks premating and throughout gestation, lactation and weaning of the F2a pups. After weaning of the F2a litters, the F2a pups were sacrificed and discarded, and the F1b animals were then re-mated to produce F2b litters. After weaning of the F2b litters, the F2b pups were sacrificed and discarded and the F1b adults were sacrificed and necropsied.

Test diets were fed continuously throughout the study. Antemortem data (i.e., clinical observations, body weights and food consumptions), reproduction data, and litter data were recorded. All F0 and F1b adults were examined macroscopically; microscopic examinations were done on the reproductive organs from the 0- and 800-ppm animals.

There were no test material-related clinical observations for F0 or F1b adults. Survival for F0 generation was 100 % for males at 0, 400 or 800 ppm and for females at 400 or 800 ppm; 96 % for males at 80 ppm and females at 0 ppm; and 92 % for females at 80 ppm. Survival for F1b generation was 100 % for males at 0, 80 and 400 ppm and for females at 0 or 800 ppm and 96 % for males at 800 ppm and females at 80 or 400 ppm.

In general, body weights and cumulative body weight gains were significantly lower than those of the controls at the 400- and 800-ppm dose levels during both generations for males and females premating, for males postmating, and for females during gestation and lactation. Body weights for males and females in the 400-ppm groups were generally 5 to 10 % lower than those of the controls. When body weights for animals in the 800-ppm groups were compared with those of the controls, F0 males were 9 to 19 % lower, F0 females were 5 to 18 % lower, F1b males were 26 to 29 % lower and F1b females were 15 to 22 % lower.The differences in cumulative body weight gains were similar to those found in body weights, except that the reductions from the controls were of a greater magnitude.

During the F0 generation, food consumptions were significantly (approximately 7 %) lower than those of the controls for the 400-ppm males (Weeks 0 to 1, 4 to 5, and 8 to 9) and for the 400-ppm females (Weeks 6 to 7).           Food consumptions for the 800-ppm F0 males and females were significantly (approximately 10 to 20 %) lower than those of the controls throughout most of the premating phase. During the F1b generation, food consumptions were significantly (approximately 7 %) lower than those of the controls for the 400-ppm males (Weeks 2 to 10) and significantly lower than those of the controls for the 400-ppm females (9 to 19 %) and 800-ppm males (19 to 25 %) and females (17 to 31 %) throughout most of the premating phase.

There were no adverse significant differences from controls in mating or male or female fertility indices during breeding for the F1a, F1b, F2a, and F2b litters. There were no significant differences from controls in female gestation indices or mean days to mate for the F1a, F1b, F2a, and F2b litters.

During the F1a, F1b, F2a, and F2b litters, there were no significant differences from controls for number of pups per litter or for pup (male and female) sex ratios. In general, the mean pup weights for most litters were significantly (approximately 10 %) lower than those of the controls at the 400-ppm dose level for Lactation Days 7, 14, and 21 and significantly lower than those of the controls at the 800-ppm dose level for Lactation Days 0, 4, 7, 14, and 21. Pup weights in the 800-ppm group on Lactation Day 21 were 36 to 43 % lower than those of the controls.

There were no test material-related macroscopic or microscopic changes.

When the test material was administered to rats continuously in the diet through 2 generations (2 litters per generation) at concentrations up to and including 800 ppm, the only treatment-related effects were decreased body weights, body weight gains and food consumptions in males and females at 400 and 800 ppm of the F0 and F1b generations. Based on these results, the no-observable-effect level was 80 ppm for systemic effects and greater than 800 ppm for male and female reproduction performance. These values are equivalent to 4 and 40 mg/kg bw/day, respectively.