Environmental pollution degree changes the biological activity of nettle plant extracts in chickens

The positive effects of plants, including stinging nettle (Urtica dioica L.) were reported by numerous researchers (1) as well as changes in the chemical composition of the plant due to heavy metal pollution (2, 3). This study aimed to compare the changes in body wight, total leukocyte numbers (TL) and delayed type hypersensitivity (DTH) in 28 days old chickens (n=12/group) injected subcutaneously twice (days 0 and 7), with 0.5 ml of alcoholic nettle extracts harvested from both unpolluted (group III) and polluted areas (group IV), against untreated (group I) and 700 alcohol treated (group II) controls. Blood was sampled three times, on days 0, 7 and 14, while the wattle test to a homologous lymphocyte suspension was performed on day 14 of the experiment. There were no significant differences in weight gain/period between groups III (0.979 kg) and IV (0.967kg), against each other and controls (0.991 kg-group II and 1.029 kg - group I, respectively). As opposed to the slight changes of the TL in control groups, there was a constant increase in group III (from 15,400±3,421/mm3 to 17,125±4,231/mm3) and a decrease in group IV (17,611.1±2,401/mm3 to 17,166.7±2,522/mm3). The wattle test results after 48 h were similar in groups I, II and IV, the differences ranging between 0.23 and 0.28 mm, while the unpolluted nettle extract diminished the DTH to a difference of 0.07 mm. The polluted nettle extract induced the lowest weight gain and TL numbers, and increased the wattle reactivity when compared to the unpolluted one.