Supernatant from the crystallisation of L-threonine from the broth filtrate from the fermentative production of L-threonine

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP study according to OECD guideline 408 (adopted 1998). Minor restrictions: Ophthalmological examination not specifically stated in the document, but weekly investigation of eyes for mydriasis, miosis, and exophthalmos as well as histopathology of eyes after termination. Study was originally judged Klimisch 1. However, according to the "Practical guide 6: How to report read-across and categories" the maximum score for read-across is 2.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Commission Directive 96/54/EEC, B.26

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Biofert Plusz

IUPAC Name:

Biofert Plusz

Details on test material:

-Name of test material (as cited in study report): Biofert Plusz
Details are presented in "Confidential details on test material"

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
-Source: Harlan Laboratories Ltd., CH
-Age at delivery: 7 weeks
-Weight at acclimatisation: 139 – 200 g
-Fasting period before study: No
-Housing: Groups of 5 animals in Macrolon type 4 cages
-Certified Diet ad libitum
-Tap water ad libitum
-Acclimation period: 7 days under test conditions after health examination. Only animals without any visible signs of illness were used

ENVIRONMENTAL CONDITIONS
-According to Guideline

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

The dose formulations were prepared weekly. Homogeneity of the test item in the vehicle was maintained during the daily administration period using a magnetic stirrer. The dose formulations were stored refrigerated in glass beakers (2 - 8°C).
Dose Volume: 10 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Results of the test item dose formulations analyses: range of 93.2 – 121.5 %. For 33 of 36 samples, the required content limit of +/- 20 % with reference to the nominal concentration was fulfilled (3 samples exceeded the upper range). All were found to be homogeneous, and all were found to be stable for four hours at room temperature and for seven days when refrigerated (2 - 8 °C).

Duration of treatment / exposure:

91 days

Frequency of treatment:

Once daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 300 and 1000 mg/kg bw/d (dry mass). Daily dose levels for the liquid test product: 0, 356, 1068 and 3559 mg/kg bw/d
Basis:

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

-Dose selection rationale: Based on a 14 d dose-range-finding study. High dose level corresponds to the limit dose recommended in OECD Guideline 408
-Rationale for animal assignment: Randomisation

Positive control:

no

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS
Yes: Twice daily

CLINICAL OBSERVATIONS
Yes: The animals were observed for clinical signs once before commencement of administration as well as twice daily on days 1 – 3 and once daily on days 4 – 91 (treatment period)

BODY WEIGHT
Yes: Body weights were recorded weekly during the acclimatization and treatment periods and before necropsy

FOOD CONSUMPTION AND COMPOUND INTAKE
Yes: The food consumption was recorded once during the acclimatization period and weekly thereafter

FOOD EFFICIENCY
Yes: The mean absolute food consumption and the mean relative food consumption of the treated rats compared with controls

OPHTHALMOSCOPIC EXAMINATION
No: However once weekly investigation of mydriasis, miosis, and exophthalmos

HAEMATOLOGY
Yes: Collection of blood from all animals (fasted) once after 13 weeks of exposure. Used anaesthetic was isoflurane. Examined parameters: According to guideline

CLINICAL CHEMISTRY
Yes: Time schedule for all animals (fasted): see haematology. Examined parameters: According to guideline

URINALYSIS
Yes: Urine was collected during the 18 hours fasting period (see haematology) into a specimen vial, using a metabolism cage. Examined parameters: According to guideline

DETAILED BEHAVIORAL OBSERVATIONS:
Yes: Once weekly (all rats): The animals were observed in their home cages, outside their home cages in a standard arena and in the hand. These observations were performed once before commencement of administration and once weekly (weeks 1 to 12) thereafter. Examined parameters: piloerection, salivation, hunched posture, ataxia, tremor/twitching, prostration, circling, spasm, hyperactivity, somnolence, increased exploration, reduced grooming, vocalisation, dyspnoea, tachypnoea, bradypnoea. Reflexes: blink, pinna, iridic light reflex, push-off (hind leg), pain response, startle/hearing, righting reflex. Other: lacrimation, limbs cyanotic, mydriasis, miosis, exophthalmos, reduced muscle tone

FUNCTIONAL OBSERVATION BATTERY
Yes: During week 13 (all animals). Relevant parameters: Grip strength and locomotor activity

Sacrifice and pathology:

GROSS PATHOLOGY
Yes: Organ wet weights as recommended in guideline

HISTOPATHOLOGY
Yes: As recommended in guideline

Other examinations:

no

Statistics:

Dunnett-test, Steel-test, Fisher's exact-test. Statistical analysis of: Body weights, clinical laboratory data, locomotor activity, grip strength, organ weights and ratios as well as macroscopic findings.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

Even at the highest dose tested (1000 mg/kg bw) no significant adverse effects were found. There were some minor changes in investigated parameters such as haematology or clinical chemistry, however these findings were considered to be within the range of normal biological variation and therefore without toxicological relevance.

Effect levels

Dose descriptor:

NOAEL

Effect level:

> 1 000 mg/kg bw/day (nominal)

Based on:

other: dry mass of the liquid test item

Sex:

male/female

Basis for effect level:

other: No adverse effects at the highest dose level tested (corresponds to the limit dose recommended in OECD Guideline 408)

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In a 13 week gavage study according to OECD Guideline 408 in male and female Wistar rats, no effects of toxicological relevance were detected even at the high dose level of 1000 mg/kg bw/d (related to dry mass).