Modification in the acute oral toxicity of zinc phosphide due to isolation stress in the laboratory rat (Rattus norvegicus albino).

Zinc phosphide is one of the widely used acute rodenticide to combat different
rodent pests throughout the world. However, because of its lower LD50 values to
most other forms of life, its use has been restricted for indoor purposes. While some
factors viz., age, sex, carrier, temperature, protein content of the diet etc. have been
found to alter/influence the toxicity of various pesticidal compounds, information
regarding the influence of housing condition on the toxic¡ty of chemicals, especially
the rodenticides are meagre.
Hence, this paper discusses in detail the behavioural responses of the
laboratory rat (Rattus norvegicus, albino) bred, reared and housed in different
controlled conditions of isolation and groups to the acute oral toxic¡ty of zinc
phosphide for the first time. It was observed that the LD50 values obtained were of
the order of 21.2 mg/kg body weight and 150 mg/kg body weight for "isolated" and
"group housed" rats respectively indicating the influence of "isolation stress" in
the test rodent. Further, observations on behaviour also pointed out that the acute
oral toxic¡ty of Zinc phosphide could be modified depending upon the housing pattern
and also their breeding environment prior to their use.