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EC number: 602-927-1 | CAS number: 123312-89-0
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Toxicity to reproduction
Administrative data
- Endpoint:
- two-generation reproductive toxicity
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Study period:
- 27 Jan 1992 to 21 Oct 1992
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 1 993
- Report date:
- 1993
Materials and methods
Test guidelineopen allclose all
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)
- Version / remarks:
- May 1983
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EPA OPP 83-4 (Reproduction and Fertility Effects)
- Version / remarks:
- 1982
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- other: Japanese MAFF 59 NohSan No. 4200
- Version / remarks:
- January 1985
- Deviations:
- no
- GLP compliance:
- yes
- Limit test:
- no
- Justification for study design:
- SPECIFICATION OF STUDY DESIGN FOR EXTENDED ONE-GENERATION REPRODUCTION TOXICITY STUDY WITH JUSTIFICATIONS:
- Premating exposure duration for parental (P0) animals: 10 weeks
- Premating exposure duration for P1 animals: weaning (indirect) and 10 weeks direct dosing.
- Basis for dose level selection: The dietary dose concentrations were selected for this study based on a previous rangefinding study
- Route of administration : Oral, via feed.
Test material
- Reference substance name:
- 6-methyl-4-[(E)-[(pyridin-3-yl)methylidene]amino]-2,3,4,5-tetrahydro-1,2,4-triazin-3-one
- EC Number:
- 602-927-1
- Cas Number:
- 123312-89-0
- Molecular formula:
- C10H11N5O
- IUPAC Name:
- 6-methyl-4-[(E)-[(pyridin-3-yl)methylidene]amino]-2,3,4,5-tetrahydro-1,2,4-triazin-3-one
- Test material form:
- solid: particulate/powder
Constituent 1
Results and discussion
Results: P0 (first parental generation)
Effect levels (P0)
open allclose all
- Dose descriptor:
- NOAEL
- Remarks:
- General toxicity
- Effect level:
- 200 ppm
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- body weight and weight gain
- food consumption and compound intake
- histopathology: non-neoplastic
- Remarks on result:
- other: equivalent to 13.92 and 15.98 mg/kg bw/day for males and females, respectively
- Dose descriptor:
- NOAEL
- Remarks:
- Reproductive toxicity
- Effect level:
- >= 2 000 ppm
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- not determinable due to absence of adverse toxic effects
Target system / organ toxicity (P0)
- Critical effects observed:
- no
Results: P1 (second parental generation)
Effect levels (P1)
open allclose all
- Dose descriptor:
- NOAEL
- Remarks:
- General toxicity
- Effect level:
- 200 ppm
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- body weight and weight gain
- organ weights and organ / body weight ratios
- histopathology: non-neoplastic
- Remarks on result:
- other: equivalent to 13.92 and 15.98 mg/kg bw/day for males and females, respectively
- Dose descriptor:
- NOAEL
- Remarks:
- Reproductive toxicity
- Effect level:
- >= 2 000 ppm
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- not determinable due to absence of adverse toxic effects
Target system / organ toxicity (P1)
- Critical effects observed:
- no
Results: F1 generation
Effect levels (F1)
- Dose descriptor:
- NOAEL
- Generation:
- F1
- Effect level:
- 200 ppm
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- body weight and weight gain
- food consumption and compound intake
- other: Delayed eye opening
Target system / organ toxicity (F1)
- Critical effects observed:
- no
Results: F2 generation
Effect levels (F2)
- Dose descriptor:
- NOAEL
- Generation:
- F2
- Effect level:
- 200 ppm
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- body weight and weight gain
- food consumption and compound intake
- other: Delayed eye opening
Target system / organ toxicity (F2)
- Critical effects observed:
- no
Overall reproductive toxicity
- Reproductive effects observed:
- yes
- Lowest effective dose / conc.:
- 2 000 ppm
- Treatment related:
- yes
- Relation to other toxic effects:
- reproductive effects as a secondary non-specific consequence of other toxic effects
- Dose response relationship:
- yes
- Relevant for humans:
- yes
Any other information on results incl. tables
Test article: Analysis of the samples of the test article in the diet were conducted on samples mixed on January 23. The results confirmed the stability of the mixes for at least 4 weeks and the homogeneity of the preparations at all concentrations.
In the F0 generation mean daily test substance intakes were approximately 1 to 4, 10 to 40, and 110 to 440 mg/kg bw/day at the feeding levels of 20, 200, and 2000 ppm, respectively.
F0 - parents: There were no treatment - related mortalities or clinical signs in parent animals. Body weights were about 10 % lower than control at 2000 ppm in both sexes from the second week of treatment onwards. Feed consumption was reduced at 2000 ppm in both sexes except in females during the lactation period.
Table 1. Reproductive performance F0 generation
Feeding level |
0 ppm |
20 ppm |
200 ppm |
2000 ppm |
||||
Males: |
||||||||
- Used for mating [n] - Mating indexa[%] - Fertility indexb[%] |
30 |
96.7 82.8 |
30 |
86.7 80.8 |
30 |
90.0 92.6 |
30 |
96.7 96.6 |
Females: |
||||||||
- Used for mating [n] |
30 29 24 23
96.7 82.8 95.8 95.8 |
30 26 21 21
86.7 80.8 100 100 |
30 27 25 24
90 92.6 96 96 |
30 29 28 27
96.7 96.6 96.4 96.4 |
||||
- Mated [n] |
||||||||
- Pregnant [n] |
||||||||
- With live born pups [n] |
||||||||
- Mating indexa[%] |
||||||||
- Fertility indexb[%] |
||||||||
- Gestation indexc[%] |
||||||||
- Parturition indexd[%] |
||||||||
- Gestation length [days] |
22.2 |
22.3 |
22.4 |
22.1 |
||||
|
± 0.5 |
±0.5 |
±0.5 |
±0.4 |
||||
- Precoital interval [days] |
3.7 |
4.2 |
4.3 |
4.8 |
||||
|
±3.2 |
±2.0 |
±2.7 |
±3.0 |
||||
- Implantation sites |
14.8 |
15.4 |
14.5 |
13.2 |
||||
|
±3.8 |
±2.2 |
±2.9 |
±2.9 |
||||
a = Percent animals positively mated (females) or producing positive mating (males)
b = Percent of females pregnant / percent of males producing pregnancy
c = Percentage of females with confirmed pregnancy that resulted in the birth of live pups d
d = Percentage of females with confirmed pregnancy that delivered pups
Table 2. Incidences of microscopical lesions in P0 generation
Sex |
Males |
Females |
||||||
Feeding level, ppm |
0 |
20 |
200 |
2000 |
0 |
20 |
200 |
2000 |
Liver / Total examined |
30 |
30 |
30 |
30 |
30 |
30 |
30 |
30 |
Hypertrophy |
0 |
0 |
5 |
27 |
0 |
0 |
0 |
2 |
Spleen / Total examined |
30 |
0 |
30 |
30 |
30 |
0 |
30 |
30 |
Hyperplasia of lymphatic follicles |
0 |
- |
0 |
0 |
0 |
0 |
0 |
25 |
Mating, gestation, fertility, and parturition indices were not affected by treatment (Table 1). Likewise, numbers of stillborn pups as well as livebirth, viability, and lactation indices were not affected.
At parental necropsy, females at 2000 ppm had higher absolute and relative liver and spleen weights than controls. No treatment-related macroscopical changes were detected.
Microscopic histopathology revealed a minimal hepatocellular hypertrophy in most males and 2 out of 30 females at 2000 ppm and in few males at 200 ppm (Table 2). Additionally, minimal to moderate hyperplasia of lymphatic follicles of splenic white pulp was observed in most females at 2000 ppm.
F1 - pups: No treatment-related clinical signs in the pups were reported (Table 3).
Litter weights of the F1 generation were reduced at 2000 ppm from the second week of lactation onwards.
Eye opening was minimally delayed (by about 0.4 days) at 2000 ppm compared to controls.
Table 3. Litter data of the F1 generation
Feeding level |
0 ppm |
20 ppm |
200 ppm |
2000 ppm |
Parameter |
||||
Number of litters |
23 f |
21 |
24 |
27 |
Total pups born |
292 f |
299 |
309 |
316 |
Mean per litter |
12.7 d |
14.2 |
12.9 |
11.7 |
Number of stillborn pups |
3 f |
2 |
12* |
6+ |
Sex ratio (% females day 0) |
46.7 |
53.5 |
52.5 |
51.0 |
Mean number of pups alive |
|
|
|
|
- on day 0 |
12.6 f |
14.1 |
12.4 |
11.5 |
- on day 4 (post culling) |
7.9 f |
8.0 |
7.9 |
7.5 |
- on day 7 |
7.8 f |
8.0 |
7.9 |
7.4 |
- on day 14 |
7.5 f |
7.9 |
7.7 |
7.4 |
- on day 21 |
7.4 f |
7.8 |
7.6 |
7.4 |
Viability IndexaLactation Indexb |
97.6 f 93.7 f |
98.0 97.6 |
97.0 96.1 |
97.1 98.5 |
Mean pup weight |
|
|
|
|
- on day 0 |
6.2 d |
6.1 |
6.6 |
6.6 |
- on day 4 precull |
9.9 d |
9.5 |
10.4 |
10.0 |
- on day4 postcull |
10.0 d |
9.6 |
10.4 |
10.1 |
- on day 7 |
16.5 d |
15.9 |
16.9 |
15.9 |
- on day 14 |
33.9 d |
32.8 |
33.7 |
31.1* |
- on day 21 |
57.4 d |
56.2 |
58.9 |
52.8* |
a: % Pups surviving days 0 to 4; b: % Pups surviving days 4 to 21;
d = ANOVA + Dunnett-test; f = chi-square + Fishers exact: * significant at p<0.05; p = 0.508
Table 4. Reproductive performance F1 generation
Feeding level |
0 ppm |
20 ppm |
200 ppm |
2000 ppm |
Males: |
||||
- Used for mating [n] - Mating indexa[%] - Fertility indexb[%] |
30 80 91.7 |
29 86.7 92.3 |
30 83.3 96 |
30 96.7 100 |
Females: |
||||
- Used for mating [n] |
30 24 22 21
80 91.7 95.5 95.5 |
30 26 24 24
86.7 92.3 100 100 |
30 25 24 24
83.3 96 100 100 |
30 29 29 29
96.7 100 100 100 |
- Mated [n] |
||||
- Pregnant [n] |
||||
- With live born pups [n] |
||||
- Mating indexa[%] |
||||
- Fertility indexb[%] |
||||
- Gestation indexc[%] |
||||
- Parturition indexd[%] |
||||
- Gestation length [days] |
22.3 ± 0.5 |
22.2 ±0.4 |
22.2 ±0.4 |
22.2 ±0.4 |
- Precoital interval [days] |
6.2 ±3.8 |
6.0 ±5.5 |
7.0 ±5.3 |
5.3 ±4.2 |
- Implantation sites |
16.0 ±2.7 |
14.8 ±4.7 |
15.5 ±2.2 |
14.3 ±3.8 |
a = Percent animals positively mated (females) or producing positive mating (males)
b = Percent of females pregnant / percent of males producing pregnancy
c = Percentage of females with confirmed pregnancy that resulted in the birth of live pups
d = Percentage of females with confirmed pregnancy that delivered pups
F1 - parents: In the F1 generation mean daily test substance intakes were similar to the F0 generation. There were no treatment-related mortalities or clinical signs in parent animals. Body weights were about 15 % lower than control at 2000 ppm in both sexes from the start of treatment onwards. Feed consumption was reduced at 2000 ppm in both sexes.
As shown in Table 4, mating, gestation, fertility, and parturition indices were not affected by treatment. Likewise, numbers of stillborn pups as well as livebirth, viability, and lactation indices were not affected.
At parental necropsy, females at 2000 ppm had higher relative liver and spleen weights than controls. At 200 ppm., relative liver weights were increased by approx. 10 %. No treatment- related macroscopical changes were detected. As shown in Table 5, microscopic histopathology revealed a minimal hepatocellular hypertrophy in males and females at 2000 ppm and minimal to moderate hyperplasia of basophilic cells of the adenohypophysis in males at 2000 ppm. A slight increase of hepatocellular hypertrophy was noted in males treated with 200 ppm.
Table 5. Incidences of microscopical lesions in F1 parents
Sex |
Males |
Females |
||||||
Feeding level, ppm |
0 |
20 |
200 |
2000 |
0 |
20 |
200 |
2000 |
Liver / Total examined |
30 |
30 |
30 |
30 |
30 |
30 |
30 |
30 |
Hypertrophy |
0 |
0 |
2 |
26 |
0 |
0 |
0 |
10 |
Pituitary / Total examined |
30 |
30 |
30 |
30 |
30 |
30 |
30 |
30 |
hypertropy of basophilic cells |
7 |
8 |
7 |
17 |
0 |
0 |
0 |
0 |
F2 - pups: As shown in Table 6, there were no treatment-related clinical signs in the pups. Litter weights of the F1 generation were reduced at 2000 ppm from the end of the first week of lactation onwards. Eye opening was minimally delayed (by about 0.5 days) at 2000 ppm compared to controls.
Table 6. Litter data of the F2 generation
Feeding level |
0 ppm |
20 ppm |
200 ppm |
2000 ppm |
Parameter |
||||
Number of litters |
21 |
24 |
24 |
29 |
Total pups born |
302 |
310 |
355 |
393 |
Mean per litter |
14.4 |
12.9 |
14.8 |
13.6 |
Number of stillborn pups |
3 |
4 |
1 |
2 |
Sex ratio (% females day 0) |
48.2 |
50.3 |
50.6 |
54.5 |
Mean number of pups alive |
|
|
|
|
- on day 0 |
14.2 |
12.8 |
14.8 |
13.5 |
- on day 4 (post culling) |
8.0 |
7.5 |
8.0 |
7.7 |
- on day 7 |
8.0 |
7.5 |
8.0 |
7.6 |
- on day 14 |
7.9 |
7.5 |
7.9 |
7.4 |
- on day 21 |
7.9 |
7.5 |
7.9 |
7.4 |
Viability Index (a) Lactation Index (b) |
95.3 98.8 |
97.4 98.9 |
97.2 98.4 |
98.7 96.9 |
Mean pup weight |
|
|
|
|
- on day 0 |
6.1 |
6.1 |
6.0 |
6.3 |
- on day 4 precull |
9.6 |
9.8 |
9.1 |
9.1 |
- on day 4 postcull |
9.7 |
10 |
9.3 |
9.3 |
- on day 7 |
16.0 |
15.5 |
15.3 |
14.7* |
- on day 14 |
31.3 |
30.5 |
30.5 |
28.9** |
- on day 21 |
52.2 |
49.9 |
49.6 |
45.7** |
(a): % Pups surviving days 0 to 4; (b): % Pups surviving days 4 to 21;
*: significant at p<0.05; **: significant at p<0.01
Applicant's summary and conclusion
- Conclusions:
- It is concluded that reproductive parameters including gonadal function, mating behaviour, conception, parturition, lactation and weaning, as well as sex organ histopathology were not affected in this study.
The dose of 200 ppm was a NOAEL for parents and offspring. At 2000 ppm, parental and offspring body weights were reduced, and eye opening was slightly delayed in pups, and histopathology of adults revealed changes in liver, spleen, and the pituitary.
At 200 ppm, a marginal increased incidence of minimal liver hypertrophy was observed in few parental males (17 %), but this finding was not correlated with any liver weight increase at this dose level and therefore not considered as toxicological relevant. - Executive summary:
Ten weeks after initiation of exposure to the test material at dietary levels of 0, 20, 200 or 2000 ppm the Tif:RAIf (SPF) rats (30 animals per sex and dose level) were paired. Parents were mated 1:1 until positive mating occurred or for 19 days, whichever came first. After weaning and a premating period of 10 weeks, F1 animals were mated to produce the F2 generation. The animals were continuously exposed to the test substance admixed to feed in two successive generations (F0 and F1). Dams were allowed to litter and suckle naturally. Litters were culled to 4 male and 4 female pups, where possible, on day 4 post partum. Clinical signs, body weights, feed consumption, mating parameters, gestation and delivery parameters, pup survival, and physical and behavioural development (surface righting and eye opening) were recorded. A gross necropsy examination was performed on all pups not selected for mating. All parental animals were necropsied after weaning of their offspring and subjected to pathological examination. Histopathology was performed on the sexual organs and the apparent target organs liver and spleen (as identified by organ weight changes).
Test article: Analysis of the samples of the test article in the diet were conducted on samples mixed on January 23. The results confirmed the stability of the mixes for at least 4 weeks and the homogeneity of the preparations at all concentrations.
Test article: Analysis of the samples of the test article in the diet were conducted on samples mixed on January 23. The results confirmed the stability of the mixes for at least 4 weeks and the homogeneity of the preparations at all concentrations.
In the F0 generation mean daily test substance intakes were approximately 1 to 4, 10 to 40, and 110 to 440 mg/kg bw/day at the feeding levels of 20, 200, and 2000 ppm, respectively.
F0 - parents: There were no treatment - related mortalities or clinical signs in parent animals. Body weights were about 10 % lower than control at 2000 ppm in both sexes from the second week of treatment onwards. Feed consumption was reduced at 2000 ppm in both sexes except in females during the lactation period.
Table 1. Reproductive performance F0 generation
Feeding level
0 ppm
20 ppm
200 ppm
2000 ppm
Males:
- Used for mating [n]
- Mating indexa[%]
- Fertility indexb[%]
30
96.7
82.8
30
86.7
80.8
30
90.0
92.6
30
96.7
96.6
Females:
- Used for mating [n]
30
29
24
23
96.7
82.8
95.8
95.8
30
26
21
21
86.7
80.8
100
100
30
27
25
24
90
92.6
96
96
30
29
28
27
96.7
96.6
96.4
96.4
- Mated [n]
- Pregnant [n]
- With live born pups [n]
- Mating indexa[%]
- Fertility indexb[%]
- Gestation indexc[%]
- Parturition indexd[%]
- Gestation length [days]
22.2
22.3
22.4
22.1
± 0.5
±0.5
±0.5
±0.4
- Precoital interval [days]
3.7
4.2
4.3
4.8
±3.2
±2.0
±2.7
±3.0
- Implantation sites
14.8
15.4
14.5
13.2
±3.8
±2.2
±2.9
±2.9
a = Percent animals positively mated (females) or producing positive mating (males)
b = Percent of females pregnant / percent of males producing pregnancy
c = Percentage of females with confirmed pregnancy that resulted in the birth of live pups d
d = Percentage of females with confirmed pregnancy that delivered pups
Table 2. Incidences of microscoppical lesions in P0 generation
Sex
Males
Females
Feeding level, ppm
0
20
200
2000
0
20
200
2000
Liver / Total examined
30
30
30
30
30
30
30
30
Hypertrophy
0
0
5
27
0
0
0
2
Spleen / Total examined
30
0
30
30
30
0
30
30
Hyperplasia of lymphatic follicles
0
-
0
0
0
0
0
25
Mating, gestation, fertility, and parturition indices were not affected by treatment (Table 1). Likewise, numbers of stillborn pups as well as livebirth, viability, and lactation indices were not affected.
At parental necropsy, females at 2000 ppm had higher absolute and relative liver and spleen weights than controls. No treatment-related macroscopical changes were detected.
Microscopic histopathology revealed a minimal hepatocellular hypertrophy in most males and 2 out of 30 females at 2000 ppm and in few males at 200 ppm (Table 2). Additionally, minimal to moderate hyperplasia of lymphatic follicles of splenic white pulp was observed in most females at 2000 ppm.
F1 - pups: No treatment-related clinical signs in the pups were reported (Table 3).
Litter weights of the F1 generation were reduced at 2000 ppm from the second week of lactation onwards.
Eye opening was minimally delayed (by about 0.4 days) at 2000 ppm compared to controls.
Table 3. Litter data of the F1 generation
Feeding level
0 ppm
20 ppm
200 ppm
2000 ppm
Parameter
Number of litters
23 f
21
24
27
Total pups born
292 f
299
309
316
Mean per litter
12.7 d
14.2
12.9
11.7
Number of stillborn pups
3 f
2
12*
6+
Sex ratio (% females day 0)
46.7
53.5
52.5
51.0
Mean number of pups alive
- on day 0
12.6 f
14.1
12.4
11.5
- on day 4 (post culling)
7.9 f
8.0
7.9
7.5
- on day 7
7.8 f
8.0
7.9
7.4
- on day 14
7.5 f
7.9
7.7
7.4
- on day 21
7.4 f
7.8
7.6
7.4
Viability IndexaLactation Indexb
97.6 f
93.7 f
98.0
97.6
97.0
96.1
97.1
98.5
Mean pup weight
- on day 0
6.2 d
6.1
6.6
6.6
- on day 4 precull
9.9 d
9.5
10.4
10.0
- on day4 postcull
10.0 d
9.6
10.4
10.1
- on day 7
16.5 d
15.9
16.9
15.9
- on day 14
33.9 d
32.8
33.7
31.1*
- on day 21
57.4 d
56.2
58.9
52.8*
a: % Pups surviving days 0 to 4; b: % Pups surviving days 4 to 21;
d = ANOVA + Dunnett-test; f = chi-square + Fishers exact: * significant at p<0.05; p = 0.508
Table 4. Reproductive performance F1 generation
Feeding level
0 ppm
20 ppm
200 ppm
2000 ppm
Males:
- Used for mating [n]
- Mating indexa[%]
- Fertility indexb[%]
30
80
91.7
29
86.7
92.3
30
83.3
96
30
96.7
100
Females:
- Used for mating [n]
30
24
22
21
80
91.7
95.5
95.5
30
26
24
24
86.7
92.3
100
100
30
25
24
24
83.3
96
100
100
30
29
29
29
96.7
100
100
100
- Mated [n]
- Pregnant [n]
- With live born pups [n]
- Mating indexa[%]
- Fertility indexb[%]
- Gestation indexc[%]
- Parturition indexd[%]
- Gestation length [days]
22.3 ± 0.5
22.2 ±0.4
22.2 ±0.4
22.2 ±0.4
- Precoital interval [days]
6.2 ±3.8
6.0 ±5.5
7.0 ±5.3
5.3 ±4.2
- Implantation sites
16.0 ±2.7
14.8 ±4.7
15.5 ±2.2
14.3 ±3.8
a = Percent animals positively mated (females) or producing positive mating (males)
b = Percent of females pregnant / percent of males producing pregnancy
c = Percentage of females with confirmed pregnancy that resulted in the birth of live pups
d = Percentage of females with confirmed pregnancy that delivered pups
F1 - parents: In the F1 generation mean daily test substance intakes were similar to the F0 generation. There were no treatment-related mortalities or clinical signs in parent animals. Body weights were about 15 % lower than control at 2000 ppm in both sexes from the start of treatment onwards. Feed consumption was reduced at 2000 ppm in both sexes.
As shown in Table 4, mating, gestation, fertility, and parturition indices were not affected by treatment. Likewise, numbers of stillborn pups as well as livebirth, viability, and lactation indices were not affected.
At parental necropsy, females at 2000 ppm had higher relative liver and spleen weights than controls. At 200 ppm., relative liver weights were increased by approx. 10 %. No treatment- related macroscopical changes were detected. As shown in Table 5, microscopic histopathology revealed a minimal hepatocellular hypertrophy in males and females at 2000 ppm and minimal to moderate hyperplasia of basophilic cells of the adenohypophysis in males at 2000 ppm. A slight increase of hepatocellular hypertrophy was noted in males treated with 200 ppm.
Table 5. Incidences of microscopical lesions in F1 parents
Sex
Males
Females
Feeding level, ppm
0
20
200
2000
0
20
200
2000
Liver / Total examined
30
30
30
30
30
30
30
30
Hypertrophy
0
0
2
26
0
0
0
10
Pituitary / Total examined
30
30
30
30
30
30
30
30
hypertropy of basophilic cells
7
8
7
17
0
0
0
0
F2 - pups: As shown in Table 6, there were no treatment-related clinical signs in the pups. Litter weights of the F1 generation were reduced at 2000 ppm from the end of the first week of lactation onwards. Eye opening was minimally delayed (by about 0.5 days) at 2000 ppm compared to controls.
Table 6. Litter data of the F2 generation
Feeding level
0 ppm
20 ppm
200 ppm
2000 ppm
Parameter
Number of litters
21
24
24
29
Total pups born
302
310
355
393
Mean per litter
14.4
12.9
14.8
13.6
Number of stillborn pups
3
4
1
2
Sex ratio (% females day 0)
48.2
50.3
50.6
54.5
Mean number of pups alive
- on day 0
14.2
12.8
14.8
13.5
- on day 4 (post culling)
8.0
7.5
8.0
7.7
- on day 7
8.0
7.5
8.0
7.6
- on day 14
7.9
7.5
7.9
7.4
- on day 21
7.9
7.5
7.9
7.4
Viability Index (a)
Lactation Index (b)
95.3
98.8
97.4
98.9
97.2
98.4
98.7
96.9
Mean pup weight
- on day 0
6.1
6.1
6.0
6.3
- on day 4 precull
9.6
9.8
9.1
9.1
- on day 4 postcull
9.7
10
9.3
9.3
- on day 7
16.0
15.5
15.3
14.7*
- on day 14
31.3
30.5
30.5
28.9**
- on day 21
52.2
49.9
49.6
45.7**
(a): % Pups surviving days 0 to 4; (b): % Pups surviving days 4 to 21;
*: significant at p<0.05; **: significant at p<0.01
It is concluded that reproductive parameters including gonadal function, mating behaviour, conception, parturition, lactation and weaning, as well as sex organ histopathology were not affected in this study.
The dose of 200 ppm was a NOAEL for parents and offspring. At 2000 ppm, parental and offspring body weights were reduced, and eye opening was slightly delayed in pups, and histopathology of adults revealed changes in liver, spleen, and the pituitary.
At 200 ppm, a marginal increased incidence of minimal liver hypertrophy was observed in few parental males (17 %), but this finding was not correlated with any liver weight increase at this dose level and therefore not considered as toxicological relevant.
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