Myo-Inositol, hexakis(dihydrogen phosphate), sodium salt

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Data source

Reference

Reference Type:

publication

Title:

Influence of dietary calcium, phosphorus, zinc and sodium phytate level on cataract incidence, growth and histopathology in juvenile chinook salmon (Oncorhynchus tshawytscha).

Author:

Richardson NL, Higgs DA, Beames RM, McBride JR.

Year:

1985

Bibliographic source:

J Nutr. 1985 May;115(5):553-67.

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Fytic acid

EC Number:

201-506-6

EC Name:

Fytic acid

Cas Number:

83-86-3

Molecular formula:

C6H18O24P6

IUPAC Name:

cyclohexane-1,2,3,4,5,6-hexayl hexakis[dihydrogen (phosphate)]

Test material form:

not specified

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

Due to differences in the methodology, it is not possible to use this study to assess the substance classification. Overall, data are deemed to be inconclusive to classify.

Executive summary:

To determine the influence of wide variations in dietary levels of calcium, zinc and phytic acid (as sodium phytate) on growth and cataract incidence, juvenile chinook salmon held at 10-11 degrees C were fed daily to satiation for 105 d one of nine purified diets containing one of three levels (grams/kilogram) of calcium (averaged 4.8, 17.7, 50.2), zinc (averaged 0.05, 0.15, 0.39) and phytic acid (1.62, 6.46, 25.8). Diets were formulated to have a calcium-phosphorus ratio of close to unity when considering phosphorus sources other than sodium phytate. High dietary phytic acid concentration (25.8 g/kg) depressed chinook salmon growth, food and protein conversion [protein efficiency ratio (PER)] and thyroid function, increased mortality, promoted cataract formation (zinc at 0.05 g/kg) and induced anomalies in pyloric cecal structure. Calcium at 51 g/kg (or phosphorus) exacerbated the effects of high dietary phytate and low dietary zinc on cataract incidence. Moreover, high dietary levels of calcium (48-51 g/kg) coupled with phosphorus significantly impaired the growth and appetite of low phytic acid (1.62 g/kg) groups and led to nephrocalcinosis in low and high phytic acid groups. Plasma zinc levels were directly related to dietary zinc concentration and inversely related to dietary phytic acid level. Calcium (51 g/kg) and/or phosphorus reduced zinc bioavailability when the diet concurrently contained 0.05 g zinc and 25.8 g of phytic acid per kilogram.