Pesticide residues in food — 2006: Toxicological ... - ipcs inchem

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gestation. The vehicle was 1% Cremophor EL/water. Rats were observed daily for mortality and
signs of toxicity. Body weights were recorded daily, and food consumption was recorded on days
6, 11, 16 and 21 of gestation. On day 21 of gestation, dams were killed and ovaries and gravid uteri
were removed by caesarean section for assessment of potential developmental effects. About one out
of three of the live fetuses in each litter were fixed and examined for visceral changes, the remaining
fetuses were examined for skeletal effects. Statements of adherence to GLP and QA were included.
No treatment-related signs or mortalities were observed. No treatment-related effect on
body-weight gain (with or without gravid uterine weight) was observed. Necropsy revealed
no effect of treatment on pre- or postimplantation loss, litter size, fetal viability or fetal body
weight. Furthermore the incidences of malformations and fetal variations were not affected by
treatment.
The NOAEL for maternal and embryo/fetotoxicity was 10 mg/kg bw per day, i.e. the highest
dose tested (Becker, 1983).
Rabbits
Groups of 15 inseminated female Himalayan rabbits (strain CHBB:HM) were given technicalgrade
cyfluthrin (purity, 95.0%) at a dose of 0, 5, 15 or 45 mg/kg bw per day by gavage on days
6–18 of gestation. The vehicle was 0.5% Cremophor EL. Rabbits were observed for clinical signs of
toxicity, and were weighed periodically during gestation. On day 29 of gestation, rabbits were killed
and uteri were examined to assess the effects of treatment on fetal development. Fetuses were weighed
and examined for visceral and skeletal abnormalities. The description of the study was concise.
No effects on mortality, behaviour, appearance, insemination rate, or maternal weight gain
were observed. At the highest dose, two rabbits aborted on days 25 and 28 of gestation, and one
rabbit completely resorbed its implants. Fetal body weight, placental weights or litter size were not
affected by treatment. No effect of treatment on the incidences of visceral or skeletal abnormalities
was observed. Arthrogryposis was seen in rabbits of all treatment groups. However, the incidence
was not dose-dependent and this malformation was reported by the study authors to be one of the
most common spontaneous malformations in this strain, with an incidence of 0.76%. Therefore, the
occurrence of arthrogryposis was considered to be spontaneous.
On the basis of the two abortions and a single case of complete resorption, the NOAEL for
maternal and embryo/fetotoxicity was 15 mg/kg bw per day (Roetz, 1983).
In a study of developmental toxicity that was performed according to OECD guideline
414, groups of 16 pregnant Chinchilla rabbits (Chb:CH hybrids, SPF) received cyfluthrin (purity,
96.0–96.1%) at a dose of 0, 20, 60, or 180 mg/kg bw per day by gavage on days 6–18 of gestation.
Mortality, clinical signs and body weight were assessed daily. Food consumption was measured
during days 0–6, 6–11, 11–15, 15–19, 19–24 and 24–28 of gestation. The dams were killed 28 days
after mating and necropsied. Fetuses were examined for visceral and skeletal anomalies. Statements
of adherence to GLP and QA were included.
Mortality and clinical signs were not affected by treatment. Food consumption and body
weight were reduced in animals at 60 and 180 mg/kg bw per day, and were increased 24–28
days after mating. When compared with does in the control group, food consumption during the
treatment period was decreased by 7, 26 and 40% in the groups at the lowest, intermediate and
highest dose, respectively. When compared with their body weight on day 6, the does in the groups
at the intermediate and highest dose showed a body-weight loss of 4% and 5%, respectively, during
treatment, while in the control group and the group at the lowest dose, body-weight loss was only
0.5% during the same period. A dose-related, statistically significant increase in postimplantation
loss, due to increased embryonic resorptions, was observed in rabbits at the intermediate and
CYFLUTHRIN AND BETA-CYFLUTHRIN X-X JMPR 2006