Fatty acids, C18-unsatd., dimers, di-Me esters, hydrogenated

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental 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

Study period:

12 May - 23 June 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study, tested with the source substance fatty acids, C18-unsatd., dimers (CAS No. 61788-89-4). In accordance to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Reference 2

Reference Type:

secondary source

Title:

Clubb, S. 2003. Dimer (CAS No. 61788-89-4) Reproduction/Developmental Toxicity Screening Test. Report Number 22828. Inveresk Research, Tranent, Scotland, as cited on the US EPA CHEMRTK website.

Author:

HPVIS - US EPA

Year:

2005

Bibliographic source:

http://www.epa.gov/chemrtk/pubs/summaries/ftadmrtr/c13651tc.htm

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Fatty acids, C18-unsatd., dimers

EC Number:

500-148-0

EC Name:

Fatty acids, C18-unsatd., dimers

Cas Number:

61788-89-4

IUPAC Name:

61788-89-4

Details on test material:

- Name of test material (as cited in study report): Dimer (complex mixture of distillation products)
- Physical state: light amber liquid
- Substance type: UVCB
- Analytical purity: no data
- Lot/batch No.: #PC-00-96
- Expiration date of the lot/batch: 19 June 2006
- Storage condition of test material: at ambient room temperature under nitrogen in the dark

Test animals

Species:

rat

Strain:

other: Sprague-Dawley Rat/IGS (Crl: CD®(SD) IGS BR)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd., Margate, Kent, UK
- Age at study initiation: approx. 6 weeks
- Weight on arrival: 145 - 165 g (males); 102 - 138 g (females)
- Housing: Animals were initially housed 2/cage by sex in polypropylene cages (42 x 27 x20 cm) with solid bottoms and mesh tops. Each cage was provided with a stainless steel food hopper and a polypropylene of polycarbonate water bottle. Shavings were supplied for bedding.
A few days prior to pairing for mating, males were housed individually in grid-bottomed cages (58 x 38.5 x 20 cm) of similar design. Mated females were housed individually in solid-bottomed cages (42 x 27 x 20 cm). Sterilised white wood shaving were supplied for bedding and white paper tissue for nesting.
Wooden chewsticks were provided for environmental enrichment.
- Diet: Rat and Mouse Breeder Diet No. 3 (Expanded Ground) SQC (Special Diets Services Ltd., Stepfield, Witham, Essex, UK), ad libitum
- Water: domestic mains water, ad libitum
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 2
- Humidity (%): 50 ± 15
- Air changes (per hr): c. 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: acetone was used for preparing diet pre-mixes and then withdrawn by ventilation

Details on exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): Batches of diet were prepared at convenient intervals (not further specified) and used within 12 days of preparation.
- Mixing appropriate amounts with (Type of food): Appropriate amounts of test material were dissolved in suitable volumes of acetone, and this solution was added to suitable quantities of untreated diet, which was then mixed for ca. 1 h with fan-assisted venting to aid the removal of acetone in order to form a dose pre-mix. A control pre-mix was prepared using the same proportion of acetone and untreated diet.
Diets the mid- and high-dose groups were prepared by diluting the dose pre-mix with untreated diet to the target concentration. The low-dose diet was prepared by diluting the mid-dose diet with untreated diet. Diet pre-mixes were placed in a Winkworth mixer for ca. 20 min.
The control diet was prepared by diluting the control pre-mix with untreated diet resembling the same proportion of pre-mix diet as in the high-dose diet.

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: up to 7 days
- Proof of pregnancy: vaginal plug and/or sperm in vaginal smear referred to as day 0 of pregnancy
- After 7 days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged (how): individually (see Details on test animals and environmental conditions)

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Diet formulations were analysed on 2 occasions during the study treatment period(for Week 1 and Week 4). Analysis of formulated diets was undertaken with regard to concentration and homogeneity. On each occasion, triplicate samples of 50 g were withdrawn from each formulated diet containing test item, and from the Control diet. The samples were using a method supplied by the Sponsor and previously validated in the testing facility.
This method was not validated to the lowest dose level (200 ppm) owing to problems encountered with analysing these products at such low levels. It was therefore agreed that the analysis of the higher levels, from which this level would be formulated, would be sufficient along with confirmation from the dispensary data to indicate correct formulation of the diet. The results from the analysis of the diet for Group 2 (200 ppm) have been reported for completeness.
In addition, on one occasion Group 2 samples were retained and analysed 14 days later to confirm the stability of the samples over that period. This work was performed out with the protocol.

Results of Analysis 1 (mean of n = 3) for Week 1:
200 ppm: 176 ppm (-12.0% difference from nominal concentration)
2000 ppm: 1770 ppm -11.5%)
20000 ppm : 16849 ppm (15.8%)
20000 ppm (re-analysis): 20862 ppm (+4.3%)

Results of Analysis 2 (mean of n= 3) for Week 4:
200 ppm: 155 ppm (-22.5% difference from nominal)
200 ppm (re-analysis): 173 ppm (-13.5%)
2000 ppm: 2109 ppm (+5.5%)
20000 ppm: 20609 ppm (+3.0%)

± 15% of the nominal concentration indicated an acceptable accuracy of formulation.
The low coefficient of variation (5.6% or less) was indicative of satisfactory homogeneity in all dose groups.

Duration of treatment / exposure:

Males: at least 4 weeks, from 2 weeks prior to mating until termination
Females: from 2 weeks prior to mating, through mating and gestation until at least Day 4 of lactation

Frequency of treatment:

daily, 7 days/week

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
200, 2000 and 20000 ppm
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
14.5, 147 and 1450 mg/kg bw/day (males)
Basis:
other: group mean achieved dose levels calculated based on food consumption, nominal dietary concentration and body weight (worst-case assumption of doses)

Doses / concentrations 3

Remarks:

Doses / Concentrations:
16.5 166 and 1692 mg/kg bw/day (females)
Basis:
other: group mean achieved dose levels calculated based on food consumption, nominal dietary concentration and body weight (worst-case assumption of doses)

No. of animals per sex per dose:

10

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: Dose levels were selected on the basis of existing relevant toxicological data. Selected dose levels considered the maximum tolerated dose in the test animal and other factors such as anticipated human exposure.

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations:
Males: once during the week prior to start of dosing and weekly thereafter.
Females: once during the week prior to the start of dosing and weekly thereafter until the start of the mating period. Afterwards, on Days 0, 7, 14 and 20 of gestation, and on Days 1 and 4 of lactation (where Day 0 = the day of parturition).

FOOD CONSUMPTION AND COMPOUND INTAKE:
- 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

WATER CONSUMPTION AND COMPOUND INTAKE: Yes
- Time schedule for examinations: once weekly by visual inspection

Oestrous cyclicity (parental animals):

Estrous cycle length was evaluated in by vaginal smears starting on the day of pairing until mating had occurred.

Sperm parameters (parental animals):

Parameters examined in P male parental generations:
testis weight, epididymis weight

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of externally visible anomalies, body weight (Day 1 and Day 4 of lactation), physical or behavioural abnormalities, presence of milk in the stomach

GROSS EXAMINATION OF DEAD PUPS:
Yes, for external abnormalities; no, for internal abnormalities; possible cause of death was not determined for pups born or found dead.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals, once mating was completed and the animals had been dosed for at least 4 weeks.
- Maternal animals: All surviving animals, between Day 4 and 6 of lactation.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS
Males: testes and epididymides were weighed, and the epididymides, seminal vesicles, coagulating gland, prostate gland and pituitary were fixed in 10% neutral buffered formalin. The testes were fixed in Bouin’s fluid.
A section from each epididymis, and a transverse section from each testis were stained with Haematoxylin and Eosin (H&E) and a further section from each testis was stained with PAS-Haematoxylin. These sections were evaluated by a pathologist. No histological examination was conducted on the other preserved tissues and organs.
Females: The female reproductive tract was dissected out and the number of implantation sites in the uterus was recorded. The reproductive tract was then fixed in 10% formalin.
A section from each ovary was stained with Haematoxylin and Eosin (H&E). These sections were evaluated by a pathologist. No histological examination was conducted on the other preserved tissues and organs.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring were sacrificed at 4-6 days of age.
- These animals were not subjected to post-mortem examinations.

Statistics:

Body weight and food consumption data in animals prior to mating were subjected to analysis of variance or the Kruskal-Wallis non-parametric analysis as appropriate.
Organ weight data were analysed by analysis of variance and analysis of covariance using the terminal bodyweight as the single covariate.
Histological data were analysed by Fisher’s Exact Probability test.
All statistical tests were two-sided and performed at the 5% significance level. Pairwise comparisons were only performed against the control group

Reproductive indices:

Fertility index (female) = (No. pregnant) / (No. paired)
Fertility index (male) = (No. siring a litter) / (No. paired)
Gestation index = (No. bearing live pups) / (No. pregnant)

Offspring viability indices:

Birth index = (Total No. of pups born (live and dead)) / (No. of implantation scars)
Live birth index = (No. of pups live on Day 0 of lactation) / (Total No. born (live and dead))
Viability index = (No. of pups live on Day 4 of lactation) / (No. live on Day 0 of lactation)

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

2000 ppm (f): 2 premature deaths (incidental); all groups (m/f): piloerection (randomly distributed, no dose-response relationship)

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

2000 and 20000 ppm (m): transiently and/or slightly decreased body weight gain (non-adverse)

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

2000 and 20000 ppm (m): transiently and/or slightly decreased body weight gain (non-adverse)

Organ weight findings including organ / body weight ratios:

no effects observed

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Test substance intake: All groups (m/f): slight decrease in compound intake towards the end of the study (non-adverse)

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
No mortality occurred in the control and the 200 and 20000 ppm groups. At 2000 ppm, there were 2 premature deaths (females). One animal was found dead after displaying several clinical signs including staining, piloerection, rolling gait, subdued behaviour, pale discoloured skin and swollen/damaged tail. At necropsy, all tissues were found to be autolysed and the left horn of the uterus was enlarged. The other animal was killed prematurely due to a prolapse of the vagina and was found to have a small thymus at necropsy. These death were considered to be incidental.
Piloerection was evident in 1/10, 5/10 and 3/10 males and 3/10, 2/10 and 1/10 females in the control, 200 and 2000 ppm groups, respectively. At 20000, piloerection was evident in 8/10 males; in females, the incidence was essentially comparable to that of the control group. Given the distribution of the findings and the lack of dose relationship, it was not possible to establish an association with treatment.
Clinical observations and necropsy findings for all other animals were considered to be consistent with those normally seen in rats of this age and strain.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
At 20000 ppm, treatment was associated with a decrease in mean body weight gain males during the first week; thereafter, weight gain was essentially similar to that of the control group. There was no effect on body weight (gain) in females. Food consumption in males was essentially similar to that of the control. In females, food consumption was slightly increased during Days 0-4 of lactation.
In the 2000 ppm group, there was a slight reduction in body weight gain in males. This minor difference was considered to reflect the low body weight noted at the start of the treatment. There were no obvious treatment-related effects on body weight in females. There was a statistically significant increase in food consumption in females during the first week of treatment; thereafter, consumption was comparable to that of the control group. Given the lack of dose-response relationship, this finding was considered to be not treatment-related.
There were no obvious treatment-related effects on body weight in males and females in the 200 ppm group. Food consumption was essentially similar to that of the control group.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS)
The achieved dietary intake for females in the 20000 group was lower in the first week than in the second week (1886 vs. 2190 mg/kg bw/day). Among males treated with 20000 ppm a higher mean dietary intake was achieved during the first week (1889 mg/kg bw/day) than in the following weeks (Week 2: 1875 mg/kg bw/day; Week 4: 1450 mg/kg bw/day).
In addition, there was a decreased concentration in females throughout the gestation period in all treatment groups (Table 1). During this period, the achieved concentrations at all levels were slightly less than proportional to the diet concentrations.
At other times, the achieved concentration was essentially proportional to the diet concentrations.

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
There were no effects on estrous cycle.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
There were no effects on mating performance, fertility or duration of gestation. The male and female fertility index was 100% among all dose groups. The median number of nights to a positive mating sign was, 2, 2, 4, and 3 nights for 0, 200 ppm, 2000 ppm, 20000 ppm, respectively. There were no animals passing one estrous to positive mating. The mean duration of gestation did not differ between control and treatment groups.

ORGAN WEIGHTS (PARENTAL ANIMALS)
There were no effects on testes and epididymides weights.

GROSS PATHOLOGY (PARENTAL ANIMALS)
In the female rat of the 2000 ppm dose group found dead, all tissues were autolysed and the left horn of the uterus was enlarged. In the other female of the same dose group killed prematurely due to a prolapse of the vagina a small thymus was seen.
Pelvic dilation in the right kidney in one female rat of the 200 ppm group and distended urinary bladder in one male rat of the 200 ppm group were considered to be not treatment-related. No further necropsy findings were noted in any of the dose groups.

HISTOPATHOLOGY (PARENTAL ANIMALS)
There were no abnormalities at examination of ovaries in the control and high dose females.
At the examination of testes, minimal seminiferous epithelial degeneration (bilateral) was observed in one male of the 20000 group. No abnormalities in testes were seen in control rats. At the examination of the epididymis in the 20000 ppm group and control group chronic inflammatory cell infiltration was noted in three treated animals and in one control animal, respectively. In another control animal chronic inflammation (focal, adnexal) of the epididymis were seen. Minimal cellular debris (luminal, bilateral) was identified in one male at 20000 ppm. However, these findings in testes and epididymis were considered to be not treatment-related.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

systemic and reproductive toxicity

Effect level:

>= 1 450 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: slight decrease in body weight gain and increase in piloerection; achieved intake equivalent to 20000 ppm in diet (worst-case assumption)

2

Dose descriptor:

NOAEL

Remarks:

systemic and reproductive toxicity

Effect level:

>= 1 692 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: no treatment-related effects; achieved intake equivalent to 20000 ppm in diet (worst-case assumption)

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:

not examined

Histopathological findings:

not examined

Details on results (F1)

VIABILITY (OFFSPRING)
The mean number of implants per pregnancy was higher in all treatment groups in comparison with the control group. However, historical data showed that the findings in the treated groups were within background ranges for animals of this age and strain in similar studies performed at the testing facility. It was considered most likely, that the control value was at the lower end of the background range and thus, these findings were considered to be not treatment-related.
There were no obvious treatment effects on litter size or survival in any group.

BODY WEIGHT (OFFSPRING)
There were no obvious treatment effects on pup and litter weights.

OTHER FINDINGS (OFFSPRING)
There were no abnormalities noted among pups.

Effect levels (F1)

Dose descriptor:

NOAEL

Remarks:

developmental toxicity

Generation:

F1

Effect level:

>= 1 692 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no treatment-related effects

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Table 1: Parental examinations

	Control group	200 ppm	2000 ppm	20000 ppm
Body weight gain (g)
Males Week 0	288 ± 18	284 ± 14	277 ± 11	282 ± 15
Males Week 1	331 ± 22	323 ± 12	320 ± 17	313 ± 18
Males Week 2	370 ± 29	374 ± 18	358 ± 22	361 ± 24
Males Week 3	404 ± 36	409 ± 19	387 ± 26	394 ± 29
Males Week 4	432 ± 37	437 ± 23	411 ± 29	417 ± 39
Males Week 0-4	144 ± 22	153 ± 13	134 ± 21	135 ± 25
Females Week 0-2	41 ± 12	43 ± 8	38 ± 7	37 ± 7
Females Day 0-20 of gestation	139	143	140	146
Females Day 4 of lactation	287 ± 18	290 ± 12	294 ± 20	293 ± 22
Food consumption (g)
Females Week 0	21.0 ± 1.2	18.0 ± 3.9	18.2 ± 2.0	18.2 ± 2.1
Females Week 1	18.1 ± 2.8	17.9 ± 0.5	20.2 ± 0.6 **	19.1 ± 0.8
Females Week 2	24.3 ± 3.2	21.5 ± 2.2	22.3 ± 1.9	24.2 ± 0.9
Females Day 0-4 of lactation	26.5	22.7	27.9	29.2
Group mean achieved dosages of test item (mg/kg bw/day)
Males Week 1	-	18.6	201	1889
Males Week 2	-	18.4	177	1875
Males Week 4	-	14.5^1	147^1	1450^1
Females Week 1	-	18.4	202	1886
Females Week 2	-	19.9	204	2190
Females Day 0-7 of gestation	-	19.4	189	1980
Females Day 7-14 of gestation	-	18.6	184	1836
Females Day 14-20 of gestation	-	16.5^1	166^1	1692^1
Females Day 1-4 of lactation	-	16.6	199	2097
Absolute epididymides weights (g)
Males	1.1258 ± 0.0809	1.1205 ± 0.0548	1.0607 ± 0.0611	1.0555 ± 0.1157
Absolute testes weights (g)
Males	3.39 ± 0.16	3.48 ± 0.32	3.36 ± 0.24	3.38 ± 0.35

** significantly different from control P<0.01

¹: These values represent the “worst-case” achieved intakes, which were taken into account for hazard assessment.

 Table 2: Reproductive and offspring examinations

	Control group	200 ppm	2000 ppm	20000 ppm
Mean duration of gestation and overall litter performance values
Mean number pregnant	10	10	10	10
Mean duration of gestation (days)	21.7	21.8	21.6	21.7
Number of females producing a liver litter	10	10	9	10
Gestation index (%)	100	100	90	100
Mean number of implant sites^aper pregnancy	12.9± 2.3	15.6 ± 0.8	14.7 ± 2.6	15.2 ± 1.9
Mean total number of pups^aborn per litter	11.8 ± 2.0	14.1 ± 1.6	13.0 ± 1.8	14.1 ± 1.6
Mean number of live pups per litter Day 0 of lactation	11.8 ± 2.0	14.1 ± 1.6	12.9 ± 2.0	13.7 ± 1.8
Mean number of live pups per litter Day 4 of lactation	11.6 ± 2.0	12.1 ± 3.4	12.6 ± 2.1	12.0 ± 3.9
Group mean F1 survival indices
Birth index (%)	91	91	91^b	92
Live birth index (%)	99	100	99^b	93
Viability Index Days 0-4(%)	79	87	86^b	82
Group mean litter and pup weight^a
Litter Day 1 of lactation (g)	78 ± 10	73 ± 22	79 ± 12	82 ± 11
Litter Day 4 of lactation (g)	112 ± 13	105 ± 30	116 ± 18	111 ± 35
Males Day 1 of lactation (g)	7.0± 0.8	6.0 ± 0.9	6.5 ± 0.6	6.4 ± 0.9
Males Day 4 of lactation (g)	10.0 ± 1.3	8.9 ± 1.1	9.5 ± 0.9	9.0 ± 1.1
Females Day 1 of lactation (g)	6.5 ± 0.8	5.6± 0.9	6.2 ± 0.5	6.1 ± 1.0
Females Day 4 of lactation (g)	9.5 ± 1.3	8.5 ± 1.2	9.1 ± 0.7	8.8 ± 1.3

^a: excludes litters where all pups died

^b: based on 8 litters (litters of animal found dead and of animal killed prematurely were not considered)