Neodecanoic acid

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

Deviations from test guideline were not specified. Protocol and SOP deviations were reported and none of the deviations were considered to have impacted the overall integrity of the study or the interpretation of the study results.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Details on test material:

SMILES Notation: O=C(O)C(C)(CC)CC(C)CCC

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Ninety-six (96) time-mated female New Zealand White [Crl:KBL(NZW)] rabbits were received from Envigo Global Services, Inc., Denver, PA . The body weight range for the female rabbits on study was 2903 g to 3800 g on the day of arrival. The rabbits were 5-9 months of age upon arrival at the Testing Facility. Healthy mated females were assigned to groups using a computer based randomization procedure, following body weight assessment on GD 0. Ninety-six (96) female rabbits were assigned to 1 groups (Groups 1 through 4), 24 rabbits per group.

The rabbits were individually housed in units of six to eight cages. No nesting materials were supplied because female rabbits assigned to this study were euthanized before parturition was expected. Target temperatures of 59°F to 70°F (15°C to 21°C) with a relative target humidity of 30% to 70% were targeted. A 12 hour light/12 hour dark cycle was maintained. Ten or greater air changes per hour with fresh air (no air recirculation) were maintained in the animal room.

Apple-flavored basal diet (Rabbit LabDiet® 5322/Apple) was offered to all animals during acclimation at the Testing Facility, to the control group throughout the study, and was used to prepare the pelleted test diets. Test and basal diets were offered during the treatment period. The certified feed was available from individual stainless steel feeders attached to each cage. The food was analyzed for environmental contaminants and results of the analysis are on file at the Testing Facility.

On the day of arrival, each rabbit was provided approximately 10 g/day of Certified Timothy hay (Bio Serv® #S1013-CS) hay in the food hopper. Suspended chain link devices hanging from the stainless steel cages were supplied to all rabbits during the course of the study.

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Remarks:

basal fed diet

Details on exposure:

Female rabbits (presumed pregnant) were administered the basal diet or test diet through continuous oral dietary feed throughout gestation days (GD) 7 through 29.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The analyzed dietary formulations contained 99.6% to 104% of the test substance which was within the protocol specified range of target concentrations, were homogenous, and were stable with the following exception. The 4-day stability assessment of the pre-pelleted (meal) diet failed at 87.9% of the pre storage concentration. This had no impact on the quality or integrity of the study because 1-day pre-pellet stability has been previously established (Gump, 2020, Study No. 00438035), and all diets were mixed and pelleted in the same day. No test substance was detected in the analyzed basal diet that was administered to the control group.

Details on mating procedure:

Female rabbits were naturally bred at the Supplier, by breeder male rabbits of the same source and strain, before shipment to the Testing Facility. The day mating occurred was considered to be gestation day (GD) 0. The rabbits were shipped to the Testing Facility after mating to arrive on GD 2-4. The Supplier forwarded breeding records and GD 0 body weights.

Duration of treatment / exposure:

Gestation day 7 to 29

Frequency of treatment:

Continuously throughout gestation

Duration of test:

23 days

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

27 000 ppm (nominal)

Remarks:

912 mg/kg/day (actual)

Doses / concentrations 2

Dose / conc.:

13 500 ppm (nominal)

Remarks:

486 mg/kg/day (actual)

Doses / concentrations 3

Dose / conc.:

4 050 ppm (nominal)

Remarks:

157 mg/kg/day (actual)

Doses / concentrations 4

Dose / conc.:

0 ppm (nominal)

Remarks:

0 mg/kg/day (actual)

No. of animals per sex per dose:

24 females/dose

Control animals:

yes, plain diet

Details on study design:

The dose levels were selected based on information provided by the Sponsor. The high dose, 27,000 ppm (approximately equivalent to the limit dose of 1000 mg/kg/day) was selected based on results (i.e., decreased mean maternal body weight gain) from a dose range-finding study in pregnant rabbits. (Charles River Laboratories, 2020, Study No. 00438037). The lower dose levels were anticipated to produce minimal maternal toxicity.

Examinations

Maternal examinations:

The animals were assessed for viability at least twice daily during the study. The animals were observed for general appearance at least once during the acclimation period, daily before test diet administration during the test period, and the day of scheduled euthanasia. Postdose observations were recorded between 1 hours and 2 hours after dose administration and at the end of the working day. Body weights were recorded on GD 0 (Supplier), on the day of arrival at the Testing Facility, at least once prior to initiation of dose administration, daily during the dose period, and on the day of scheduled euthanasia. Food consumption was recorded daily during acclimation and daily during the dose period, and on the day of euthanasia.

A gross necropsy of the thoracic, abdominal and pelvic viscera was performed for all rabbits found dead or euthanized prior to scheduled termination without knowledge of dose group. Gross necropsy included an evaluation of the external and internal surfaces of the stomach, large intestine and small intestine and these organs were retained for possible future evaluation.

Ovaries and uterine content:

The reproductive tract was dissected and removed from the abdominal cavity. The gravid uterus was weighed. The uterus was opened and the contents were examined. The fetuses were removed from the uterus and placed in individual containers. The ovaries and uterus were examined for number and distribution of corpora lutea, implantation sites, placentae (size, color, or shape), live and dead fetuses, and early and late resorptions. Uteri of apparently nonpregnant animals were examined while being pressed between glass plates to confirm the absence of implantation sites. Uteri and ovaries of apparently nonpregnant animals were retained in 10% neutral buffered formalin.

Fetal examinations:

Fetal body weights and sex ratios, and fetal external, visceral, coronal and skeletal morphology were evaluated. All fetuses were examined for sex and external abnormalities. Late resorptions and dead fetuses were examined for external abnormalities and sex to the extent possible. The body weight of each fetus was recorded. All fetuses in each litter were examined for visceral abnormalities by using a modification of the microdissection technique of Staples. Each fetus was fixed in Bouin's solution and the heads were subsequently examined by free-hand sectioning; head sections were stored in alcohol. The decapitated carcasses were not retained. Each eviscerated fetus, following fixation in alcohol, will be macerated in potassium hydroxide and stained with Alizarin Red S and Alcian Blue were examined for skeletal abnormalities.

Statistics:

Numerical data and clinical and necropsy observations were summarized by sex and occasion or by litter. Data from nongravid females were excluded from calculation of means and from comparative statistics.

Any data collected during the predose period was not tabulated, summarized or statistically analyzed. All statistical tests were conducted at the 5% significance level. All pairwise comparisons were conducted using two sided tests and were reported at the 1% and 5% levels, unless otherwise noted.

Maternal body weight, body weight gains, food consumption, hormone variables, and litter observations were analysed with parametric/non-parametric analysis. Levene’s test was used to assess the homogeneity of group variances. The groups were compared using an overall one-way ANOVA F test if Levene’s test was not significant or the Kruskal-Wallis test if it was significant. If the overall F-test or Kruskal-Wallis test was found significant, then pairwise comparisons were conducted using Dunnett’s or Dunn’s test, respectively.

Ovarian/uterine parameters and fetal malformations/variations were subjected to non-parametric analysis. The groups were compared using an overall Kruskal-Wallis test. If the overall Kruskal-Wallis test was found significant, then the above pairwise comparisons were conducted using Dunn’s test.

For parental indices and mortality, a Fisher’s exact test was used to conduct pairwise group comparisons of interest.

Indices:

Pre Implantation Loss (%) = (No. of corpora lutea – no. of implants)/(No. of corpora lutea) x 100

Post Implantation Loss (%) = (No. of implants – no. of live fetuses)/(No. of implants) x 100

Historical control data:

Historical control data were attached (see attached in the information panel) including results from 208 studies for fetal body weight, 210 studies for fetal external, soft tissue and skeletal abnormalities. See attachment in information panel.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

There was an increased incidence in the clinical sign: feces, abnormal output decreased in the 13,500 and 27,000 ppm groups (3 and 6 animals, compared to 0 in controls), respectively. This slight increase was not considered to be adverse because this was only observed for 1-2 days in these animals.

The remaining clinical signs (i.e., fur: wet, stained, thin; skin:scab; feces:abnormal, smeared, reduced; broken: toenail) in the 4050, 13,500 and 27,000 ppm groups were considered unrelated to administration of the test substance because the observations recorded were singular occurrences within a group, were present at incidences that lacked a dose-response relationship and/or were similar to those seen in basal diet fed rabbit and were not adverse.

Mortality:

no mortality observed

Description (incidence):

There was no test substance related mortalities or moribundities in any dose group.

One female in each of the control and 4050 ppm groups was euthanized prior to scheduled termination for reasons unrelated to test substance administration. One female in the control group was euthanized on GD 8 due to a suspected fracture; a macroscopic observation of a fractured tibia confirmed the in-life observation. One female in the 4050 ppm group was assigned to study despite low food consumption from GD 5–7 prior to the start of test diet administration. This animal was subsequently euthanized due to low food consumption and body weight loss. These animals were substituted with available spares.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

There was a decrease in mean maternal body weight gain in the 13,500 ppm and 27,000 ppm groups from GD 13–20 ( 26% and 26% decreased body weight gain compared to the control group, respectively). However, body weight gains from GD 20–29 were comparable to the control group, thereafter. These changes had minimal impact on absolute body weight as mean values in either group were ≤ 4.2% lower than control throughout gestation. Additionally, mean corrected body weight loss was observed in each group compared to corrected body weight gain in the control group with minimal differences noted for mean corrected body weight. Therefore, the body weight effects noted in these groups were considered test substance related, but nonadverse.

In the 4050 ppm group, mean maternal body weight gains were generally comparable to the control with the exception of transient mean body weight loss noted from GD 7–10 (-3.1 g) at the initiation of test diet feeding. Mean corrected body weight was comparable to controls thereafter on GD 29. Mean gravid uterine weights in all test substance groups were also comparable to the control group. Therefore, the changes in mean maternal body weight were considered nonadverse.


Dose in ppm (# of Dams)
0 ppm (24) 4,050 (24) 13,000 (22) 27,000 (22)

Interval - Gestation Days
grams, mean (SD)
7 to 10 35.8 (78.7) -3.1 (39.8) 19.6(51.1) 12.5 (57.7)
10 to 13 118.3 (66.9) 110.5 (73.6) 87.3 (43.0) 75.0 (43.5)
13 to 20 151.4 (48.7) 144.4 (53.3) 112.7(46.5)* 111.4(66.4)*
20 to 29 181.4(72.9) 155.4 (107) 206.1 (75.9) 206.0 (56.4)

* Kruskal-Wallis & Dunn: * = p ≤ 0.05; ** = p ≤ 0.01

Dose in ppm (# of Dams)
0 ppm (24) 4,050 (24) 13,000 (22) 27,000 (22)

Gestation Day 29
grams, mean (SD)

Gravid Uterus Wt 486.07 (125.05) 517.62 (69.31) 519.92 (87.79) 474.36 (62.33)

Corrected BW 3277.9 (169.9) 3181.6 (243.9) 3134.3 (217) 3163.8 (157.6)

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

In the 13,500 ppm and 27,000 ppm groups, lower mean food consumption was observed generally throughout the study and corresponded to body weight gain differences observed in these groups. These differences were considered test substance related but nonadverse because decreases in diet consumption were transient and did not result in a significant effect on absolute mean body weight at study termination.

In the 4050 ppm group, lower mean food consumption was observed from GD 23–29 compared to the control group; values in this group from GD 7-23 had been generally comparable to control. These lower values in late gestation had no impact on mean absolute body weight or body weight gain and were considered test article related but non adverse.

Dose in ppm (# of Dams)
Interval - Gestation Days
Mean
0 ppm (24) 4,050 (24) 13,000 (22) 27,000 (22)

7 to 15 1191.15 1185.00 1298.05 850.49**
15 to 20 742.09 726.96 657.59** 605.14**
20 to 29 1240.00 1077.59 1031.04** 1189.78


* Anova & Dunnett: * = p ≤ 0.05; ** = p ≤ 0.01

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 substance-related gross pathological findings in any group. There were no placental findings. The findings were of singular occurrance, were not observed in a dose-response manner, were considered incidental, of the nature commonly observed in this strain and age of rabbit, and/or were of similar incidence in control; and therefore, were considered unrelated to administration of Neo Decanoic Acid Diet.


Dose in ppm (# of Dams)

0 ppm (24) 4,050 (24) 13,000 (22) 27,000 (22)
GALLBLADDER
Dilatation 0 1 0 0


OVARY
Cyst, clear; fluid 1 0 0 0

OVIDUCT
Cyst, clear; fluid 7 8 3 4

SKIN
Material accumulation; brown, abdominal; urogenital 0 0 0 1
Material accumulation; yellow, hindfoot 0 0 0 1

SPLEEN
Abnormal appearance 4 3 2 5

UTERUS
Material accumulation; red, horn 1 0 0 0

BONE, TIBIA
fractured 1 0 0 0

COLON
adhesion 0 1 0 0

WHOLE ANIMAL
No Visible Lesions 15 15 19 15

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Maternal developmental toxicity

Number of abortions:

no effects observed

Description (incidence and severity):

There were no abortions on this study.

Dose in ppm (# of Dams)

0 ppm (25) 4,050 (24) 13,500 (22) 27,000 (22)

Aborted 0 0 0 0

Pre- and post-implantation loss:

effects observed, non-treatment-related

Description (incidence and severity):

There were no effects on pre- or postimplantation loss in any dose group. The changes observed were similar to concurrent controls, were not observed in a dose-response manner and were considered unrelated to administration of Neo Decanoic Acid Diet.

Dose in ppm (# of Dams)

0 ppm (24) 4,050 (24) 13,500 (22) 27,000 (22)


Post-implantation Loss (%)
Mean 9.77 3.33 7.21 3.11
SD 12.90 7.04 10.51 6.53
%Diff - -65.93 -26.20 -68.22

Pre-implantation Loss (%)
Mean 17.34 16.19 15.80 17.95
SD 16.52 10.23 11.66 13.00
%Diff - -6.65 -8.87 3.51

Total litter losses by resorption:

no effects observed

Description (incidence and severity):

There were no total litter losses by resorption in any group.

Dose in ppm

0 ppm 4,050 13,500 27,000

Female with Live Fetuses 25 24 22 22
% 100.0 100.0 100.0 100.0

Female with all Nonviable 0 0 0 0
% 0.0 0.0 0.0 0.0

Early or late resorptions:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test substance-related increases in early or late resorptions in any group. The changes observed were similar to concurrent controls, were not observed in a dose-response manner and were considered unrelated to administration of Neo Decanoic Acid Diet.

Dose in ppm (# of Dams)

0 ppm (24) 4,050 (24) 13,500 (22) 27,000 (22)

Total Number of Resorptions
Mean 0.8 0.3 0.7 0.3
SD 1.1 0.7 1.1 0.6
%Diff - -60.0 -12.7 -67.3

Number of Early Resorptions
Mean 0.7 0.3 0.6 0.2
SD 1.1 0.7 0.9 0.5
%Diff - -58.8 -16.6 -67.9

Number of Late Resorptions
Mean 0.1 0.0 0.1 0.0
SD 0.4 0.2 0.4 0.2
%Diff - -66.7 9.1 -63.6

Dead fetuses:

no effects observed

Description (incidence and severity):

There were no dead fetuses observed in this study.

Dose in ppm (# of Dams)

0 ppm (24) 4,050 (24) 13,500 (22) 27,000 (22)

Number of Dead Fetuses
Mean 0.0 0.0 0.0 0.0
SD 0.0 0.0 0.0 0.0

Changes in pregnancy duration:

no effects observed

Description (incidence and severity):

There were no test substance-related effects on duration of pregnancy in any dose group. There were 2 females that were euthanized early due to a broken leg or body weight loss. All remaining females survived until scheduled termination.

Dose (ppm)
0 4,050 13,500 27,000
Terminal Euthanasia
N 24 24 24 24
% 96.0 96.0 100.0 100.0

Changes in number of pregnant:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test substance-related changes in the number of pregnant females in any group. There were 2 females on GD 29 in each group (13,500 ppm and 27,000 ppm) that were nongravid. All remaining females were gravid. Due to the low incidence of non pregnant females, the changes observed were similar to control animals in this species; and therefore, were considered unrelated to administration of Neo Decanoic Acid Diet.

Observed Dose (ppm)
0 4,050 13,500 27,000

Number of Females Pregnant
N 25 24 22 22
% 100.0 96.0 91.7 91.7

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

27 000 ppm (nominal)

Based on:

test mat.

Basis for effect level:

other: In the mid- and high-dose levels, there were test substance related transient decreases in mean maternal body weight and food consumption; however, these findings were not considered to be adverse because body weights were comparable to controls on GD 29.

Results (fetuses)

Fetal body weight changes:

no effects observed

Description (incidence and severity):

There were no test substance-related changes in mean fetal weights for sexes combined, males, and females in any dose group. The variations in fetal body weight were similar to concurrent controls, were not observed in a dose-response manner, were unrelated to administration of Neo Decanoic Acid Diet; and therefore, were considered nonadverse.

Observation Dose (ppm)
0 4,050 13,500 27,000
Mean Fetal Weight (both) (g)
Mean 41.63 40.12 41.37 42.21
SD 4.57 4.24 3.00 3.51
N 24 24 22 22
%Diff - -3.64 -0.64 1.38

Mean Fetal Weight (M) (g)
Mean 42.03 40.69 42.25 42.85
SD 4.27 4.83 3.54 3.82
N 24 24 22 22
%Diff - -3.20 0.51 1.94

Mean Fetal Weight (F) (g)
Mean 40.71 39.41 40.74 41.62
SD 4.78 4.24 3.50 3.78
N 23 23 22 22
%Diff - -3.20 0.07 2.23

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

There were no test substance-related changes in number of live offspring in any dose group. The variations in numbers of live offspring were similar to concurrent controls, were not observed in a dose-response manner, were unrelated to administration of Neo Decanoic Acid Diet; and therefore, were considered nonadverse.

Observation Dose (ppm)
0 4,050 13,500 27,000

Number of Live Male Fetuses
Mean 4.5 4.7 4.4 4.4
SD 2.0 1.7 1.9 1.3
N 24 24 22 22
%Diff - 3.7 -2.0 -3.0

Number of Live Female Fetuses
Mean 3.9 4.8 4.6 3.9
SD 1.8 2.2 1.8 1.2
N 24 24 22 22
%Diff - 22.3 18.4 -1.4

Changes in sex ratio:

no effects observed

Description (incidence and severity):

There were no test substance-related changes in mean fetal sex ratios in any dose group. The variations in fetal sex ratios were similar to concurrent controls, were not observed in a dose-response manner, were unrelated to administration of Neo Decanoic Acid Diet; and therefore, were considered nonadverse.

Observation Dose (ppm)
0 4,050 13,500 27,000
Live Male Fetus/Litter (%)
Mean 54.39 50.35 48.26 52.95
SD 18.88 18.42 18.77 12.40
N 24 24 22 22
%Diff - -7.43 -11.29 -2.66

Changes in litter size and weights:

no effects observed

Description (incidence and severity):

There were no test substance-related changes in litter size and weights in any dose group. The variations in litter size and weights were similar to concurrent controls, were not observed in a dose-response manner, were unrelated to administration of Neo Decanoic Acid Diet; and therefore, were considered nonadverse.

Observation Dose (ppm)
0 4,050 13,500 27,000
Total Number of Fetuses
Mean 8.4 9.5 9.0 8.2
SD 2.7 2.0 1.8 1.4
N 24 24 22 22
%Diff - 12.4 7.5 -2.3

Number of Live Fetuses
Mean 8.4 9.5 9.0 8.2
SD 2.7 2.0 1.8 1.4
N 24 24 22 22
%Diff - 12.4 7.5 -2.3

Gravid Uterus Wt
Mean (SD) 486.07 (125.05) 517.62 (69.31) 519.92 (87.79) 474.36 (62.33)

Changes in postnatal survival:

not examined

External malformations:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test substance related fetal external malformations or variations noted in any dose group. There was a single fetus in the 27,000 ppm group, that exhibited the malformation: cleft face. Since this was a singluar occurrence and the value was within the range of historical controls in the laboratory, it was unrelated to administration of Neo Decanoic Acid Diet.; and therefore, was considered nonadverse.

Observation Dose (ppm)
0 4,050 13,500 27,000

Number of Fetuses Examined: 202 227 199 181
Number of Fetuses Evaluated: 204 228 201 182
Number of Litters Examined: 24 24 22 22
Number of Litters Evaluated: 24 24 22 22

Face
Malformation Fetuses
Face, Cleft Face -
N(%) 0(0.00) 0(0.00) 0(0.00) 1(0.57)
Litters N(%) 0(0.0) 0(0.0) 0(0.0) 1(4.5)

[Fetuses %] - Kruskal-Wallis & Dunn
FetusesN(%) N=Group Fetal Incidence;(%)=Mean Litter % of Fetuses with the Abnormality

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test substance-related fetal skeletal malformations or variations observed. All variations in skeletal findings (i.e., malformations, variations, incomplete ossifications), were of single occurrence, were similar to those seen in basal diet fed dams, were not observed in a dose-response manner, and/or were within historical control; and therefore, were considered unrelated to administration of Neo Decanoic Acid Diet and considered nonadverse.


Observation Dose (ppm)
0 4,050 13,500 27,000

Number of Fetuses Examined: 202 227 199 181
Number of Fetuses Evaluated: 204 228 201 182
Number of Litters Examined: 24 24 22 22
Number of Litters Evaluated: 24 24 22 22

Rib
Rib, Nodule - Variation
Fetuses N(%) 0(0.00) 1(0.46) 0(0.00) 0(0.00)
Litters N(%) 0(0.0) 1(4.2) 0(0.0) 0(0.0)

Skull
Hyoid ala, Bent - Variation
Fetuses N(%) 12(7.66) 6(2.75) 4(2.73) 11(7.03)
Litters N(%) 7(29.2) 6(25.0) 3(13.6) 5(22.7)

Hyoid body, Unossified - Variation
Fetuses N(%) 1(0.32) 0(0.00) 1(0.45) 0(0.00)
Litters N(%) 1(4.2) 0(0.0) 1(4.5) 0(0.0)

Sternebra
Sternebra, Branched - Variation
Fetuses N(%) 1(0.32) 0(0.00) 0(0.00) 0(0.00)
Litters N(%) 1(4.2) 0(0.0) 0(0.0) 0(0.0)

Sternebra, Fused - Variation
Fetuses N(%) 2(0.80) 2(0.76) 3(1.41) 0(0.00)
Litters N(%) 2(8.3) 2(8.3) 3(13.6) 0(0.0)

Sternebra, Misaligned - Variation
Fetuses N(%) 2(0.93) 2(0.93) 0(0.00) 0(0.00)
Litters N(%) 1(4.2) 2(8.3) 0(0.0) 0(0.0)
Sternebra, Unossified - Variation
Fetuses N(%) 31(14.71) 37(16.96) 12(6.03) 17(10.39)
Litters N(%) 13(54.2) 14(58.3) 7(31.8) 10(45.5)

Sternebra, Incomplete ossification - Variation
Fetuses N(%) 31(15.02) 24(11.04) 13(6.54) 22(12.51)
Litters N(%) 16(66.7) 12(50.0) 10(45.5) 11(50.0)

Sternebra, Isolated ossification site - Variation
Fetuses N(%) 2(1.01) 0(0.00) 0(0.00) 1(0.57)
Litters N(%) 2(8.3) 0(0.0) 0(0.0) 1(4.5)

Xiphoid cartilage, Hole - Variation
Fetuses N(%) 7(3.02) 4(1.68) 4(1.82) 2(1.22)
Litters N(%) 3(12.5) 3(12.5) 1(4.5) 2(9.1)

Supernumerary rib
Cervical, Short - Variation
Fetuses N(%) 0(0.00) 0(0.00) 1(0.51) 0(0.00)
Litters N(%) 0(0.0) 0(0.0) 1(4.5) 0(0.0)

Thoracolumbar, Full - Variation
Fetuses N(%) 74(34.89) 61(25.98) 83(43.18) 67(38.32)
Litters N(%) 19(79.2) 18(75.0) 21(95.5) 20(90.9)

Thoracolumbar, Short - Variation
Fetuses N(%) 44(21.53) 69(30.60) 54(26.31) 45(24.73)
Litters N(%) 19(79.2) 23(95.8) 19(86.4) 17(77.3)

[Fetuses %] - Kruskal-Wallis & Dunn
FetusesN(%) N=Group Fetal Incidence;(%)=Mean Litter % of Fetuses with the Abnormality

Visceral malformations:

effects observed, non-treatment-related

Description (incidence and severity):

There were no test substance-related fetal visceral malformations or variations observed. The variations in visceral findings were limited to a single fetus, not observed in a dose-response manner, similar to those seen in basal diet fed dams and/or were within historical control; and therefore, were unrelated to administration of Neo Decanoic Acid Diet and considered nonadverse.

Observation Dose (ppm)
0 4,050 13,500 27,000

Number of Fetuses Examined: 202 227 199 181
Number of Fetuses Evaluated: 204 228 201 182
Number of Litters Examined: 24 24 22 22
Number of Litters Evaluated: 24 24 22 22

Aorta
Aorta, Dilatation -
Malformation Fetuses N(%) 0(0.00) 0(0.00) 1(0.91) 0(0.00)
Litters N(%) 0(0.0) 0(0.0) 1(4.5) 0(0.0)

Diaphragm
Diaphragm, Hernia -
Malformation Fetuses N(%) 0(0.00) 1(0.38) 0(0.00) 0(0.00)
Litters N(%) 0(0.0) 1(4.2) 0(0.0) 0(0.0)

Gallbladder/bile duct
Gallbladder, Absent -
Variation Fetuses N(%) 1(0.52) 0(0.00) 1(0.57) 2(1.52)
Litters N(%) 1(4.2) 0(0.0) 1(4.5) 1(4.5)

Gallbladder, Small -
Variation Fetuses N(%) 1(0.42) 3(1.30) 4(2.02) 4(2.67)
Litters N(%) 1(4.2) 3(12.5) 3(13.6) 3(13.6)

Gonad
Oviduct, Cyst -
Variation Fetuses N(%) 0(0.00) 0(0.00) 1(0.45) 0(0.00)
Litters N(%) 0(0.0) 0(0.0) 1(4.5) 0(0.0)

Kidney
Kidney, Malpositioned -
Malformation Fetuses N(%) 0(0.00) 1(0.60) 0(0.00) 0(0.00)
Litters N(%) 0(0.0) 1(4.2) 0(0.0) 0(0.0)

Liver
Lobe, Discolored -
Incidental Fetuses N(%) 0(0.00) 1(0.38) 0(0.00) 0(0.00)
Litters N(%) 0(0.0) 1(4.2) 0(0.0) 0(0.0)

Lung
Lobe, Absent -
Variation Fetuses N(%) 4(1.88) 1(0.35) 2(0.96) 1(0.65)
Litters N(%) 3(12.5) 1(4.2) 2(9.1) 1(4.5)

Lobe, Small - Variation
Fetuses N(%) 0(0.00) 1(0.38) 0(0.00) 0(0.00)
Litters N(%) 0(0.0) 1(4.2) 0(0.0) 0(0.0)

Spleen
Spleen, Supernumerary - Variation
Fetuses N(%) 23(11.84) 20(9.52) 21(11.45) 17(9.97)
Litters N(%) 11(45.8) 9(37.5) 12(54.5) 11(50.0)

Stomach
Stomach, Distended - Variation
Fetuses N(%) 1(1.04) 0(0.00) 0(0.00) 1(0.57)
Litters N(%) 1(4.2) 0(0.0) 0(0.0) 1(4.5)

Subclavian artery
Subclavian artery, Retroesophageal - Malformation
Fetuses N(%) 0(0.00) 0(0.00) 1(0.45) 0(0.00)
Litters N(%) 0(0.0) 0(0.0) 1(4.5) 0(0.0)

Ureter
Ureter, Retrocaval - Variation
Fetuses N(%) 1(0.83) 2(0.84) 3(1.53) 0(0.00)
Litters N(%) 1(4.2) 2(8.3) 3(13.6) 0(0.0)

Ureter, Short - Variation
Fetuses N(%) 0(0.00) 1(0.60) 0(0.00) 0(0.00)
Litters N(%) 0(0.0) 1(4.2) 0(0.0) 0(0.0)

[Fetuses %] - Kruskal-Wallis & Dunn
FetusesN(%) N=Group Fetal Incidence;(%)=Mean Litter % of Fetuses with the Abnormality

Details on embryotoxic / teratogenic effects:

There were no test substance-realted developmental toxicity findings at any dose.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

27 000 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: There were no test substance-related adverse embryo-fetal developmental toxicity findings in any dietary dose group.

Overall developmental toxicity

Key result

Developmental effects observed:

no

Applicant's summary and conclusion

Conclusions:

The maternal and developmental NOAEL in rabbits was 27,000 ppm (actual 912 mg/kg/day), the highest dose tested, as no study substance-related adverse maternal or developmental effects were observed.

Executive summary:

The objective of this study is to determine the potential for developmental toxicity of Neo Decanoic Acid in rabbits following oral (dietary) administration from Gestation Days (GD) 7 through 29, and to determine a NOAEL (no-observed-adverse-effect level) for maternal and developmental toxicity.

Timed-pregnant New Zealand White (NZW) rabbits (GD 0 = day of confirmed mating) were provided Neo Decanoic Acid in a diet of 0 (control basal diet), 4050, 13,500, 27,000 ppm (calculated equivalent (0, 157, 486, 912 mg/kg/day) continuously from Gestation Day (GD) 7 through 29 (24 rabbits/group). The females were sacrificed on GD 29 and the following parameters and endpoints were evaluated: viability, maternal clinical signs, maternal body weight and body weight gain, maternal food consumption, gross necropsy findings, ovarian and uterine examination, fetal sex ratio, embryo/fetal viability, fetal body weight, and fetal abnormalities (external, visceral, and skeletal).

There were no test substance-related mortalities, clinical signs, placental abnormalities or gross examination findings in any dose group. Two females (1 in control and 1 in the low dose) were euthanized on GD 8 and 7 due to a broken leg and body weight loss prior to study start, respectively; early euthanasia was unrelated to the test substance.

In the 13,500 ppm and 27,000 ppm groups, there was a decrease in mean maternal body weight gain from GD 13–20 (26% and 26% decreased body weight gain compared to the control group, respectively). However, body weight gains from GD 20–29 were comparable to the control group, thereafter. These differences had minimal impact on absolute body weight as mean values in either group were ≤ 4.2% lower than control by the end of the study. These changes also corresponded to lower mean food consumption observed generally throughout the study. Additionally, mean corrected body weight loss was observed in each group compared to corrected body weight gain in the control group with minimal differences noted for mean corrected body weight. Therefore, the maternal body weight effects and decreased food consumption noted in these groups were considered test substance related, but nonadverse. There were no changes in mean maternal body weight or food consumption in the 4050 ppm group. The remaining variations in mean maternal body weight and body weight gain were similar to those seen in control fed rats and were unrelated to treatment.

 

There were no test substance-related changes in developmental toxicity endpoints of embryo/fetal viability, postimplantation loss, sex ratio, body weights or examination of fetal external, visceral, or sites of incomplete ossification in any group. All variations in embryofetal examination findings observed were similar to concurrent controls, were of singular occurrence, were not observed in a dose-response manner and/or were within historical control of the testing laboratory and were not related to NeoDecanoic Acid diet.

 

In conclusion, female NZW rabbits were provided a NeoDecanoic Acid at oral dietary doses of 0 (control diet), 4050, 13,400, 27,000 ppm by fed ad libitum from GD 7 through 29. Although there were maternally toxic effects, these findings were not considered adverse. There was no evidence of Neo Decanoic Acid-related developmental toxicity in any group. Therefore, the no-observed-adverse-effect level for maternal and developmental toxicity was 27,000 ppm.