4-(5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydro-1,2-oxazol-3-yl)-N-(2-ethyl-3-oxo-1,2-oxazolidin-4-yl)-2-methylbenzamide

Toxicity to birds

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to birds: dietary toxicity test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 May 2017 to 9 June 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 205 (Avian Dietary Toxicity Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Dose method:

feed

Analytical monitoring:

yes

Vehicle:

no

Details on preparation and analysis of diet:

Test diets were prepared by mixing the test substance directly into the feed using standard laboratory mixers. An amount of diet sufficient to last the five-day exposure period was prepared on the day of test initiation for each treatment and control group. Diets were presented to the birds at test initiation.
Diet samples were collected from the 562 and 5620 ppm test concentrations, and were analysed to evaluate the homogeneity of test substance in the diet.

Test organisms (species):

Anas platyrhynchos

Details on test organisms:

Common name: Mallard ducks
Age: 5 days old
Source: Bred at test facility
Acclimatisation period: 5 days
Treatment for disease: none
Weight: 77 to 113 g

Total exposure duration (if not single dose):

5 d

Post exposure observation period:

3 days

No. of animals per sex per dose and/or stage:

10 per test concentration and 20 per control (5 birds per pen)

Control animals:

yes, plain diet

Nominal and measured doses / concentrations:

Nominal: 562, 1000, 1780, 3160 and 5620 ppm

Details on test conditions:

Replication: 2 pens per test concentration, 4 per control
Number of birds per pen: 5
Temperature: 29.7 ± 1.1 ºC
Humidity: 79% ± 7%
Photoperiod: 16 hours of light per day with average intensity of 478 lux
Birds were housed in brooding pens containing five chicks each. Each pen had a floor space of 62 x 92 cm, with a ceiling height of 25.5 cm.

Details on examinations and observations:

Test birds were observed four times on the day of test initiation, and twice daily throughout the remainder of the test. A record was maintained of all signs of toxicity and abnormal behaviour.
Individual body weights were measured at test initiation (Day 0), at the end of the exposure period on Day 5 and at termination of the test on Day 8. Average feed consumption values were determined daily during the exposure period (Days 0 – 5) and during the post-exposure observation period (Days 6-8) by pen for each treatment group and the control group. Feed consumption was determined by measuring the change in the weight of the feed presented to the birds over a given period of time. The accuracy of feed consumption values may have been affected by the unavoidable wastage of feed by the birds.
All birds at test termination were euthanized using carbon dioxide. Gross necropsies were performed on three birds from each of the levels at test termination.

Details on reproductive parameters:

Not applicable

Reference substance (positive control):

no

Key result

Duration (if not single dose):

5 d

Dose descriptor:

LC50

Effect level:

2 000 mg/kg diet

Conc. / dose based on:

test mat.

Basis for effect:

mortality

Repellency factors (if applicable):

No repellent effect of the substance was reported.

Mortality and sub-lethal effects:

There were no mortalities in the control group or the 562 ppm treatment group. The birds in the 562 ppm treatment group had minor muscle fasciculation (day 2) and a slight ruffled appearance (day 3 and 4), they were normal in appearance from day 5 to day 8 of the test. Signs of toxicity were noted in the 1000 ppm, 1780 ppm, 3160 ppm and 5620 ppm treatment groups from day 1. There was one dead bird at 1000 ppm on day 4, and 5 dead birds at 1780 ppm (three on day 3 and two on day 5). Seven mortalities occurred in the 3160 ppm treatment group on days 3 and 4 and there was total mortality at the highest concentration of 5620 ppm. All surviving birds were normal in appearance at day 8.
The body weights for the 5620 ppm treatment group could not be compared to the control due to mortality. The overall body weight change from Day 0 to day 8 was statistically lower than the control for the 1000, 1780 and 3160 ppm treatment groups.
When compared to the control group, there were no treatment-related effects on the mean feed consumption during the exposure period for the 562 and 1000 ppm treatment levels and there was a decrease in feed consumption during the exposure period for the 1780, 3160, and 5620 ppm treatment groups.

Effects on reproduction:

Not applicable

Results with reference substance (positive control):

Not applicable

Further details on results:

Mean concentrations and standard deviations for the two test concentrations were 565 ± 16.5 ppm and 5330 ± 229 ppm, respectively. Samples collected on Day 0 to verify test substance concentrations for the 1000, 1780, and 3160 ppm diets were found to be 98%, 93% and 97% of nominal concentrations, respectively. Analysis of diet samples collected from feeders after being held at ambient temperature for 5 days averaged 97%, 98%, 104%, 103% and 105% of the Day 0 values for the 562, 1000, 1780, 3160 and 5620 ppm test concentrations, respectively.

Reported statistics and error estimates:

Mean total weight change: Difference from the control group statistically significant at p ≤ 0.05 (Bonferroni t-test) at test concentrations of 1000, 1780 and 3160 ppm.
The 95% confidence interval for the dietary LC50 value was 1500 to 2679 ppm. The slope of the dose responsive curve was 4.3 and the Chi-Square value of 1.3. The no-mortality concentration was 562 ppm.

Validity criteria for the test were met:

• Birds were randomly assigned to control and treatment pens.


• The mortality in the control group did not exceed 10%.


• Concentrations of the test substance in the diet were satisfactorily maintained (at least 80% of nominal) throughout the exposure period.


• The test substance was administered in diet for five consecutive days (5 ~ 24 hr. periods).


• A minimum of ten birds were used for each control and treatment group.


• The test substance was administered in the diet.


• The definitive test of five concentration levels and a control group were tested.

Validity criteria fulfilled:

yes

Conclusions:

The dietary LC50 value for mallard was calculated to be 2000 ppm.

Executive summary:

The acute dietary toxicity to the substance to mallard ducks was studied under GLP to OECD TG 205. Birds were fed a daily diet containing 562, 1000, 1780, 3160 or 5620 ppm substance for five consecutive days (ten birds per test concentrations, bred at test facility, five days old at study initiation). A control group received untreated diet (20 birds). Following the five-day exposure period all groups were given untreated basal diet for three days. No mortalities occurred in the group receivign 562 ppm. The number of dead birds increased in a dose-dependent manner, and all birds were found dead at the highest test concentration. Some transient signs of toxicity (minor muscle fasciculation, slightly ruffled appearance) were observed in the group receiving a diet containing 562 ppm. Signs of systemic toxicity were noted in the groups receiving a diet containing 1000 ppm or higher concentrations. The acute oral LC50 for mallards exposed to the substance was determined to be 2000 ppm and the no mortality concentration was 562 ppm.

Reference 2

Endpoint:

long-term toxicity to birds: reproduction test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 February 2017 to 06 October 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 206 (Avian Reproduction Test)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Dose method:

feed

Analytical monitoring:

yes

Vehicle:

no

Details on preparation and analysis of diet:

Test diets were prepared by mixing the substance into a premix that was used for preparation of the final diet. Control diet and each of the three treated diets were prepared at least weekly and presented to the birds on Thursday of each week.

Test organisms (species):

Anas platyrhynchos

Details on test organisms:

Common name: Mallard duck
Source: Whistling Wings, Inc., 113 Washington St., Hanover, IL 61041, USA
Acclimation period: 2 weeks
Treatment for disease: none
Age: 19 weeks at exposure start
Weight: 723 to 1369 g

Limit test:

no

Total exposure duration (if not single dose):

21 wk

Remarks:

Pre-photostimulation: 9 weeks
Pre-egg laying (with photostimulation): 2 weeks
Egg laying: 11 weeks
Post-adult termination (final incubation, hatching and 14-day offspring rearing period): 6 weeks

No. of animals per sex per dose and/or stage:

18 pairs

Control animals:

yes, concurrent no treatment

Nominal and measured doses / concentrations:

Nominal: 100, 320 and 1000 ppm in diet
Analysis of the diet samples demonstrated that they had been dosed correctly, were homogenous and were stable over the test period.

Details on test conditions:

Test cages
Adult birds: Batteries of pens with floor space measuring approximately 75 x 90 cm and ceiling height of approximately 45 cm, constructed of vinyl-coated wire grid
Hatchlings: Batteries of brooding pens measuring approximately 62 x 92 x 25.5 cm constructed of vinyl-coated wire mesh

Number of birds per pen: 2

Temperature
Adult birds: 20.2 – 22.8°C (mean 21.6 ± 0.6°C)
Incubation: 37.4 ± 0°C
Hatching: 37.3 ± 0°C
Hatchlings (brooding pens): 25.7 ± 1.0°C (ambient temperature), 29 – 38°C (brooding compartment)

Humidity
Adult birds: 30 – 83% (mean 59 ± 13%)
Incubation: 55 ± 0%
Hatching: 60 ± 0%
Hatchlings (brooding pens): 75 ± 7%

Photoperiod
Adults acclimation to photostimulation: 8 hours light (421 lux)
Adults photostimulation to termination: 17 hours light (432 – 519 lux)
Hatchlings: 16 hours light

Details on examinations and observations:

The test birds were acclimated to the facilities and study pens for 2 weeks prior to initiation of the test. All adult birds were observed daily throughout the test for signs of toxicity or abnormal behaviour. Adult body weights were measured at test initiation, at the end of weeks 2, 4, 6, 8 and at adult termination. Feed consumption was measured weekly throughout the test.

Details on reproductive parameters:

Weekly, one egg was selected from each of the odd-numbered pens during odd-numbered weeks (1, 3, 5 etc.) and from each of the even-numbered pens on even-numbered weeks (2, 4, 6 etc.) for egg shell thickness measurements. All remaining eggs were candled prior to incubation to detect egg shell cracks or abnormal eggs.

Reference substance (positive control):

no

Key result

Duration (if not single dose):

21 wk

Dose descriptor:

NOEC

Effect level:

52.8 mg/kg bw/day

Conc. / dose based on:

test mat.

Basis for effect:

signs of toxicity

Key result

Duration (if not single dose):

21 wk

Dose descriptor:

NOEC

Effect level:

14.6 mg/kg bw/day

Conc. / dose based on:

test mat.

Basis for effect:

reproductive parameters

Remarks:

Decrease in mean egg shell thickness, mean body weights of 14-day old survivors and number of 14-day old survivors as a percentage of hatchlings

Repellency factors (if applicable):

No repellent effect of the substance was reported.

Mortality and sub-lethal effects:

Mallards treated with 1000 ppm SYN547407 were terminated on Day 1 of Week 9 due to signs of toxicity. There were no adult treatment-related mortalities or overt signs of toxicity at the 100 or 320 ppm.

Effects on reproduction:

Statistically significantly decreased mean egg shell thickness, mean body weights of 14-day old survivors and number of 14-day old survivors as a percentage of hatchlings were observed at 320 ppm

Results with reference substance (positive control):

Not applicable

Further details on results:

The following validity criteria for the test were met:
• Control mortality should not exceed 10% (0% observed)
• The average number of eggs laid per hen in the control should be ≥ 29 (observed 48)
• Viable embryos of eggs set at day 14 in the control should be ≥ 80% (observed 94%)
• Live 3-week embryos of viable embryos in the control should be ≥ 94% (observed 99%)
• Hatchlings of live 3-week embryos in the control should be ≥52% (observed 87%)
• Hatchlings of eggs set for incubation in the control should be ≥44% (observed 81%)
• The number of 14-day old survivors of hatchlings in the control should be ≥94% (observed 99%)
• The average egg shell thickness in the control should be ≥0.316 mm (observed 0.393 mm)
• The number of cracked eggs of eggs laid in the control should be ≤13% (observed 0%)
• The average number of 14-day-old survivors per hen in the control should be ≥ 14 (observed 35)
Acceptability criteria were also met (birds assigned randomly to treatment groups).

Reported statistics and error estimates:

Mean egg shell thickness (mm): Statistically significant difference (p ≤ 0.05) from the control group (Williams Multiple Comparison Test) in the 320 ppm test group
14-day old survivors in percent per hatchlings & mean body weight (g) of 14-day old survivors: Statistically significant difference (p ≤ 0.05) from the control group (Jonckheere-Terpstra Step-Down Test)

Summary of effects of the substance on growth and feed consumption of adult mallards (Anas platyrhynchos) following dietary exposure

	Mean body weight (g)	Mean body weight (g)	Mean body weight (g)	Mean feed consumption (g/bird/day)	Mean feed consumption (g/bird/day)	Mean feed consumption (g/bird/day)	Estimated Daily Dietary Dose (mg/kg bw/day)
	Pre-egg production	Egg-production	Overall	Pre-egg production	Egg-production	Overall	Overall
Nominal dose (ppm)	(1-10 wks)	(11-21 wks)	(1-21 wks)	(1-10 wks)	(11-21 wks)	(1-21 wks)	(1-21 wks)
Control	1036	1059	1048	106	166	138	0
100	1035	1077	1051	122	181	153	14.6
320	1012	1047	1024	134	200	169	52.8
1000*	918	-	-	97	-	-	-

* All surviving birds in the 1000 ppm treatment group were euthanised in test week 9 due to signs of toxicity

Summary of effects of the substance on reproductive parameters and hatchling growth of mallards (Anas platyrhynchos) following dietary exposure

Nominal dose (ppm SYN547407)	Total eggs laid	Mean egg shell thickness (mm)	Eggs uncracked / Eggs laid (%)	Viable embryos / Eggs set (%)	Live 3-week embryos / Viable embryos (%)	Hatchlings / Live 3-week embryos (%)	14 day old survivors / Hatchlings (%)	Mean body weight (g)	Mean body weight (g)
								Hatchlings	14-day old survivors
Control	864	0.393	100	94	99	87	99	32	298
100	804	0.392	100	94	100	88	99	33	302
320	675	0.381	100	83	99	87	95	32	270

Validity criteria fulfilled:

yes

Conclusions:

The 21-week NOEC in the reproduction toxicity study with mallard duck was 100 ppm in the diet, corresponding to a dose of 14.6 mg/kg bw/day.

Executive summary:

The effects of the substance on the mallard duck (Anas platyrhynchos) were determined under GLP in a reproduction toxicity test to OECD TG 206 with a 21-week exposure period. Mortality, body weight, feed consumption, reproductive parameters and other overt signs of toxicity were assessed at nominal dietary concentrations of 100, 320 and 1000 ppm, alongside an untreated control group.
Mallards treated with 1000 ppm were terminated on Day 1 of Week 9 due to signs of toxicity. There were no adult treatment-related mortalities or overt signs of toxicity at the 100 or 320 ppm test concentrations. Additionally, there were no treatment-related effects upon any reproductive parameters at the 100 ppm test concentration. At 320 ppm, there were reductions in egg shell thickness, offspring survival and mean body weights of 14-day old survivors. The no-observed-effect concentration for mallards exposed to the substance was determined to be 100 ppm, corresponding to 14.6 mg/kg bw/day.

Description of key information

Short-term toxicity, dietary: 5-day LC50 = 2000 ppm in diet (Mallard duck, OECD TG 205, Hubbard et al 2017)

Reproductive toxicity: 21-week NOEC = 14.6 mg/kg bw/day (Mallard duck, OECD TG 206, Hammett et al 2018)

Key value for chemical safety assessment

Short-term EC50 or LC50 for birds:

2 000 mg/kg food

Long-term EC10, LC10 or NOEC for birds:

14.6 mg/kg bw/day

Additional information

The acute, dietary short-term and reproductive toxicity of the substance to birds was tested under GLP in reliable and valid studies conducted with Mallard ducks and northern bobwhite quails to the relevant OECD test guidelines. Mallard ducks were more sensitive to exposure than northern bobwhite. The substance was not particularly acutely toxic to both tested species following the administration of a single oral dose of 2000 mg/kg bw according to OECD TG 223, and no mortalities occurred over the observation period of 14 days. The study on short-term dietary toxicity with Mallard ducks, conducted to OECD TG 205, resulted in a 5-day LC50 value of 2000 ppm in the diet. The long-term study on reproductive toxicity with Mallard ducks, conducted to OECD TG 206, gave a 21-week NOEC of 14.6 mg/kg bw/day.