Impact of fipronil, a new generation pesticide, on avian development and health

Fipronil is a new-generation pesticide aerially applied in semi-arid and agricultural areas of Australia to control locust outbreaks. Seasonal conditions that give rise to locust plagues are also ideal for breeding birds, with over 100 different avian species observed in areas of locust control operations. Despite the potential for exposure, there is very little research regarding the toxicological effects of fipronil in birds. Available avian toxicity information shows a high species-specific variability in fipronil sensitivity across the few species tested, making it extremely difficult to predict the toxicity of fipronil on unstudied species at high risk of exposure in the wild. The aim of this thesis was to increase our understanding of the impact of fipronil on native birds at risk of exposure as a result of locust-control spraying. This was done firstly by examining the toxicity, effects, and duration of symptoms following exposure to fipronil and it’s major metabolite, fipronil-sulfone, in sensitive and non-sensitive avian species; secondly by evaluating the metabolism of fipronil in a selected bird species to gain insight into the mechanisms underlying variation in species sensitivity; and thirdly by examining whether exposure to fipronil at sub-lethal levels adversely affects exposed birds and their offspring

Adverse effects of fipronil on avian reproduction and development : maternal transfer of fipronil to eggs in zebra finch Taeniopygia guttata and in ovo exposure in chickens Gallus domesticus

Two studies were carried out to examine the impact of maternal fipronil exposure on embryonic and offspring development. In the first study, breeding female zebra finches were orally dosed with single sublethal levels of fipronil (1, 5, and 10 mg/kg body weight) to determine behavioural and developmental consequences on chicks following maternal pesticide exposure. Significant levels of fipronil and fipronil-sulfone residues were detected in eggs laid by females in all dosed groups, however, these were undetectable in eggs laid 13 days after treatment. The level of sulfone detected in eggs was consistently higher than that of the parent fipronil compound. Of the seven eggs laid in the treatment groups, only one (14%) chick hatched and this was from the lowest dose group. This chick was severely underdeveloped at 10 days of age in comparison to control chicks and fiproles were detected in brain, liver, and adipose tissues collected following euthanasia of this individual. In contrast, there was 100% hatchability of control group eggs and all chicks fledged nests on schedule. In the second study, domestic chicken eggs were injected with 5.5, 17.5, and 37.5 mg/kg egg weight of fipronil directly into the yolk sac on day 12 of incubation. Treatment did not affect hatching success, however, behavioural and developmental abnormalities were observed in hatchlings from the highest dose group. These chicks also demonstrated reduced feeding rates, as indicated by reduced body mass at 48 h period post hatch. Both fipronil and fipronil-sulfone residues were detected in brain and liver tissue of hatchlings at all pesticide dose levels tested. 2011 Springer Science+Business Media, LLC