Methanaminium, N-[4-[[4-(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexadien-1-ylidene]-N-methyl-, ethanedioate

Additional ecotoxological information

Administrative data

Endpoint:

additional ecotoxicological information

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Data from literature; despite the global experiment is well documented and scientifically acceptable, details about the tested substance composition are missing.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Materials and methods

Principles of method if other than guideline:

Duplicate lots of 250 rainbow trout eggs were treated daily with malachite green oxalate at a low concentration, weekly at a high rate, or every other day at an intermediate concentration; control fish were untreated. Treatments began after the eggs had water-hardened and continued until 24 hours before eggs in the control lots began to hatch. Treatments over the 34- day incubation period. Eggs were incubated in standard Heath trays provided with a common water source (12°C) but eacht ray had a separated rain. The effluent from a treated lot was not allowed to flow through the trays containing other lots of developing eggs. Time to hatching, percent hatch, survival, and morphology were determined for each lot of eggs and larvae. All hatched fish received the same ration and were reared for 21 days after feeding began, after which they were all examined for anomalies.

GLP compliance:

not specified

Type of study / information:

Eggs treatment

Test material

Test material information

Constituent 1

Reference substance name:

Methanaminium, N-[4-[[4-(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexadien-1-ylidene]-N-methyl-, ethanedioate

EC Number:

241-922-5

EC Name:

Methanaminium, N-[4-[[4-(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexadien-1-ylidene]-N-methyl-, ethanedioate

Cas Number:

18015-76-4

Molecular formula:

C23H25N2 x C2HO4

IUPAC Name:

4-{[4-(dimethylamino)phenyl](phenyl)methylidene}-N,N-dimethylcyclohexa-2,5-dien-1-iminium hydrogen oxalate

Results and discussion

Any other information on results incl. tables

Incubation of the various lots of rainbow trout eggs progressed normally. No stresses due to temperature, low oxygen, lack of flow, or poor water quality occurred. All lots of eggs treated with malachite green experienced a delay in hatching. Lots 5 and 6 had the shortest delay (5 days) and Lots 3 and 4 the longest observed effect (8 days).

At 3 weeks after hatching, all lots were examined for gross abnormalities such as head or jaw deformities, curvatures of the spine, missing fins, or a bob-tailed condition.

Frequencies of abnormalities were 34 % in Lots 3 and 4; 27 % in Lots 5 and 6; 20 % in Lots 1 and 2 and were significantly different from that in the untreated controls( 7 %) at (P < 0.05). Growth was significantly depressed in all treated groups( P <0.05).

Response of incubating Rainbow trout eggs to treatments with Malachite Green

Response measured	Lots of MG treatment
	1 and 2	3 and 4	5 and 6	7 and 8
	1 mg/l; 1 hour daily (30 treatments)	3 mg/l; 1 hour every other day (15 treatments)	5 mg/l; 1 hour weekly (5 treatments)	Untreated controls
Median time to eyed stage in days	18	23	23	18
Percent of eggs reaching eyed stage	72	66	60	70
Percent hatch	68	96	82	70
Median time to hatching in days	42	42	37	34
Mean total length of larvae at 21 days (mm)	13	12	16	18
Percent deformities among larvae through 21 days	20	34	27	7

Applications of Malachite Green (MG) on incubating rainbow trout eggs reduced the percent of eggs that reached the eyed stage, increased the time from fertilisation to hatching, reduced the average size of larvae, and caused a significant increase in the percent of larvae with deformities. However the percent of eyed eggs that hatched increased, perhaps as a result of control of fungal infections. The use of malachite green in fish hatcheries, thus, can result in significant losses of eggs and larvae. This loss can probably be offset by starting an increased number of eggs. Deformed larvae would not be expected to survive so the true number of larvae lost to MG effects is likely to be underestimated in a hatchery situation

Applicant's summary and conclusion

Conclusions:

Applications of Malachite Green (MG) on incubating rainbow trout eggs reduced the percent of eggs that reached the eyed stage, increased the time from fertilisation to hatching, reduced the average size of larvae, and caused a significant increase in the percent of larvae with deformities.

Executive summary:

Duplicate lots of 250 rainbow trout eggs were treated daily with malachite green oxalate at a low concentration, weekly at a high rate, or every other day at an intermediate concentration; control fish were untreated. Treatments began after the eggs had water-hardened and continued until 24 hours before eggs in the control lots began to hatch. Treatments over the 34- day incubation period. Eggs were incubated in standard Heath trays provided with a common water source (12 °C) but each ray had a separated rain. Time to hatching, percent hatch, survival, and morphology were determined for each lot of eggs and larvae. Applications of Malachite Green (MG) on incubating rainbow trout eggs reduced the percent of eggs that reached the eyed stage, increased the time from fertilisation to hatching, reduced the average size of larvae, and caused a significant increase in the percent of larvae with deformities. However the percent of eyed eggs that hatched increased, perhaps as a result of control of fungal infections. The use of malachite green in fish hatcheries, thus, can result in significant losses of eggs and larvae. This loss can probably be offset by starting an increased number of eggs. Deformed larvae would not be expected to survive so the true number of larvae lost to MG effects is likely to be underestimated in a hatchery situation.

Conclusion

Applications of Malachite Green (MG) on incubating rainbow trout eggs reduced the percent of eggs that reached the eyed stage, increased the time from fertilisation to hatching, reduced the average size of larvae, and caused a significant increase in the percent of larvae with deformities.