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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
one-generation reproductive toxicity
Remarks:
based on test type (migrated information)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]
Version / remarks:
May 1983
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
soya oil
Details on exposure:
The test substance was given daily 7 times a week to 3 groups of 28 F0 male and 28 F0 female Sprague-Dawley rats by gavage. The F0 control animals (28 males and 28 females) received the vehicle Soybean Oil (SBO).
Details on mating procedure:
Each male was paired with one female of the same treatment group for the night. The female was placed with the same male until mating occurred or 10 days had elapsed. If no evidence of mating was observed after 10 days, the female was placed after 3 days rest period with another male that had already successfully mated, until mating occurred or 11 days had elapsed. Each morning, a vaginal lavage was performed in order to detect the presence of spermatozoa. The day when spermatozoa were found was designated as day 0 of pregnancy.
Duration of treatment / exposure:
(P) Males: 71 days before mating, during mating until day 21 post-partum of their F1 offspring.
(P) Females: 15 days before mating, during mating and pregnancy and lactation periods until day 21 post-partum

Frequency of treatment:
daily, 7 days each week
Doses / concentrations
Remarks:
Doses / Concentrations:
100, 300 and 1000 mg/kg bw/day.
Basis:
actual ingested
No. of animals per sex per dose:
28
Control animals:
yes, concurrent vehicle

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS:

F0 animals were observed daily for clinical signs. Any animal showing signs of poor clinical condition, especially if death appeared imminent, was asphyxiated by carbon dioxide and killed by exsanguination. Any animal found dead or killed due to poor clinical condition was subjected to macroscopic examination and a full spectrum of tissues was preserved whenever possible.

BODY WEIGHT:
Body weight was recorded for each females on the first day of treatment (day 1), once a week before mating and during mating periods, on days 0, 7, 14 and 20 of pregnancy, and on days 1, 7, 14 and 21 post-partum.

FOOD CONSUMPTION:

The quantity of food consumed by each male was recorded once a week over a 7-day period of treatment until sacrifice. The quantity of food consumed by each female was recorded as follows:
during the premating period, once a week over a 7-day period,
during pregnancy, at the intervals day 0-day 7, day 7-day 14 and day 14-day 20,
during lactation, at the intervals day 1 pp-day 7 pp, day 7pp-day 14 pp and day 14 pp-day 21 pp.
However, food consumption was not measured during the mating period. Food intake per animal and per day was calculated using the amount of food given and left in each feeder. Body weight was recorded for each males on the first day of treatment (day 1) and then once a week until sacrifice.

Litter observations:
STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: [yes]
size of each litter was adjusted by eliminating extra pups by random selection, as nearly as possible, at 4 males and 4 females per litter. Whenever, the number of male or female pups prevented having at least 4 of each sex per litter, partial adjustment (for example, 5 males and 3 females) was made.Adjustments were not made for litters of less than 8 pups.


PARAMETERS EXAMINED
The number of pups in each litter exhibiting the following characteristics was recorded:
on day 5 post-partum: pinna unfolding, hair growth, surface righting reflex
on day 11 post-partum: cliff avoidance
on day 13 post-partum: incisor eruption
on day 17 post-partum: eye opening, auricular duct opening, air righting reflex
About 24 hours after the last administration, hematology and blood chemistry investigations were performed in 5 males and 5 females of each group
Postmortem examinations (parental animals):
macroscopic examination of all F0 males and females was performed. In all the parents, reproductive organs and macroscopic lesions were sampled and additionally in 5 males and 5 females of each group ileum, kidneys and liver were sampled.

Microscopic examination of the reproductive organs was performed in all animals of the control and 1000 mg /kg bw/day groups and in animals suspected of infertility, those that died or were sacrificed in the 100 and 300 mg/kg bw/day groups. In addition the livers of one male of the 1000 mg/kg bw/day group and of the control group were also examined microscopically.
Postmortem examinations (offspring):
macroscopic examination of all F1 pups performed
Statistics:
Statistical analysis: Mean values were compared by one-way variance analysis and Dunnett's test. Percentage values were compared by Fisher's exact probability test. The following sequence was used for the statistical analysis of haematology and blood biochemistry data: The normality of the distribution of the values in each group was checked by Komolgorov Smirnov's test (1948). If the distribution was normal, the homogeneity of variances between the groups was assessed by Bartlett's test (1937)(more than 2 groups) or Fisher's test (1934) (2 groups). If no significant heterogeneity of the variances was established, the comparison between treated and control groups was performed by Dunnett's test (1955). If the variances were heterogeneous, the comparison between treated and control groups was performed by Dunn's test (1964) (more than 2 groups) or by Mann Whitney's test (1947) (2 groups). If the distribution of values in the group was not normal, the analysis was repeated after logarithmic transformation of the values. If this logarithmic transformation fails to normalise the distribution of the values, comparison of treated and control groups was performed by Dunn's test using original values.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
no effects observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Other effects:
not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
no effects observed

Details on results (P0)

Substance did not induce any toxic effects in parent males and females, did not disturb their capacity of reproduction

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)

Reproductive data: The mating and fertility indices of males and females were similar in the control and treated groups.

Litter data: The gestation index and the mean duration of gestation were similar in all groups. The live birth index was 100% in all groups. The viability indices on day 4 and day 21 post-partum, the physical and reflex development of pups and the mean pup body weight were similar in the control and treated groups.

Details Mating:
Males: The mating index of males was similar in the control group (96.4%) and the 100 (89.3%), 300 (96.4%) and 1000 (96.4%) mg/kg bw/day groups.
Females: The mating index of females was 100 % in the control group and the 100 and 300 mg/kg bw/day groups. It was 96.4% in the 1000 mg/kg bw/day group as 1 female did not mate. This is not related to the treatment.

Fertility:
Males: The fertility index of males was similar in the control group (81.5%) and the 100 (88.5%), 300 (92.6%) and 1000 (100.0%) mg/kg bw/day groups.
Females: The fertility index of females was similar in the control group (82.1%) and the 100 (92.9%), 300 (92.9%) and 1000 (100.0%) mg/kg bw/day groups.

Gestation: The mean number of implantation sites was similar in the control and treated groups. The gestation index was 100% in the control, 300 and 1000 mg/kg bw/day groups. In the 100 mg/kg bw/day group, it was 96.2% as one pregnant female was sacrificed on day 9 of pregnancy (due to
a misdosing). The mean duration of gestation was similar in all groups and within the normal range of 21-22 days. The live birth index was 100 % in all groups.

Haematology: The statistically significant differences noted between control and treated animals in some haematological parameters, namely total white and red blood cell count in males, were considered to be of no toxicological importance as they were minor, not dose-related and the individual
values were within the range of our background data (white blood cells: 5.9 - 15.6 G/l; red blood cells: 8.05 - 9.80T/1). No perceptible differences between control and treated animals in the other parameters.

GROSS PATHOLOGY (PARENTAL ANIMALS)
PATHOLOGY: Macroscopic examination: Liver enlargement, without any relevant histopathological findings, was noted in 1 out of 28 males given 1000 mg/kg bw/day. Paleness of the liver was found in 2 out of 28 males given 300 mg/kg bw/day. These findings were considered to be of spontaneous nature and irrelevant to the treatment with the test substance.


HISTOPATHOLOGY (PARENTAL ANIMALS)
Microscopic examination: Regular oestrous cycle, as evidenced from the morphological changes in the ovaries, uterus and vagina, was noted in the control and treated female rats, except in 2 females given 100 mg/kg bw/day. In these two animals deciduomatosis was noted in one female;severe metritis and degenerated placenta were noted in the other female. These changes can be found in untreated rats, therefore this weak incidence is not considered of toxicological importance. No treatment-related abnormalities were found in the male genital organs of the animals examined.

Effect levels (P0)

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Sex:
male/female

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Histopathological findings:
not examined

Details on results (F1)

No treatment-related macroscopic changes were noted in pups sacrificed at the end of the study.

VIABILITY (OFFSPRING)

The viability index on day 4 post-partum was similar in the control (94.2%) and the 100 (91.1 %), 300 (97.9%) and 1000 (93.5%) mg/kg bw/day groups. On day 21 post-partum, the lactation index was also similar in the control (97.8%) and the 100 (98.9%), 300 (97.9%) and 1000 (94.4%) mg/kg bw/day groups.

CLINICAL SIGNS (OFFSPRING)
No clinical signs attributed to the treatment were observed in pups of any group.

Effect levels (F1)

Dose descriptor:
NOAEL
Generation:
F1
Effect level:
1 000 mg/kg bw/day
Sex:
male/female

Overall reproductive toxicity

Reproductive effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
The test substance ESBO administered daily by the oral route (gavage) to male and female Sprague-Dawley rats at the 100, 300 and 1000 mg/kg bw/day dose levels 71 days before mating in males and 15 days before mating in females until day 21 post-partum of F1 litters did not induce any toxic effects in parent males and females, did not disturb their capacity of reproduction and did not impair the development of the F1 offspring. Under the experimental conditions, the highest tested dose of 1000 mg/kg bw/day was found to be the No Observed Effect Level (NOEL)