A. Massi

Serum esterase inhibition in birds: A nondestructive biomarker to assess organophosphorus and carbamate contamination

With the aim of proposing a nondestructive biomarker for monitoring the toxicological risk to birds of exposure to the organophosphorus insecticide azamethiphos and the carbamate insecticide methomyl, laboratory studies were performed on serum “B” esterases in Japanese quail (Coturnix coturnix japonica). The birds received two single dose treatments of each compound (azamethiphos and methomyl), i.e., 50 mg/kg and 250 mg/kg respectively. In the first treatment, serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) were drastically inhibited in the azamethiphos-treated group, 24 h after the dose. No inhibition was detected for BChE and CbE activities in the methomyl-treated group, 24 h after the dose. In the second treatment, the birds died or were sacrified 3 h after the dose. Serum BChE and brain acetylcholinesterase (AChE) were strongly inhibited after treatment with both insecticides. Serum CbE, hepatic microsomal CbE and 7-ethoxyresorufin dealkylation activities were also inhibited. A statistically significant correlation between serum BChE and brain AChE was found at lethal and sublethal doses of these xenobiotics. The experimental results indicate that the nondestructive biomarker BChE can give an early qualitative and semi-quantitative warning of the toxic effects of organophosphate and carbamate insecticides in birds.

Metal biomonitoring in bird eggs: A critical experiment

Bird eggs have been widely used as an indicator of exposure to persistent contaminants. Recent advances in biomonitoring tend to use multimedia environmental models including wildlife for mass balances of chemicals or in a monitor strategy for food quality. Theoretically the high protein and lipid content of the egg binds both polar and apolar chemicals. High concentrations of lipophilic contaminants and methylmercury have been described in experimental birds and wild species throughout the world but metals such as cadmium and lead have always been found at natural levels even in the eggs of birds heavily exposed to metals. These findings pose the question of the relationship between environmental and egg levels of metals. The existence of a metabolic mechanism preventing the transfer of metals into the eggs would disqualify this as a method of monitoring metals. The air of the present paper is to investigate the capacity of bird eggs to reflect the environmental input of inorganic forms of mercury, cadmium and lead so that the validity of this biological sample in environmental studies can be assessed.

Blood esterase inhibition in birds as an index of organophosphorus contamination: field and laboratory studies.

With the aim of developing a nondestructive biomarker (serum ‘B’ esterases) for monitoring bird populations exposed to azamethiphos S((6-chloro-2-oxooxazolo(4,5-b)pyridin-3(2H)-yl)methyl) 0,0-dimethyl phosphorothioate (9Cl), parallel laboratory and field studies were performed. In japanese quail (Coturnix coturnix japonica) treated with azamethiphos at 10 mg kg−1, serum butyrylcholinesterase (BChE) and carboxylesterase (CE) activities were inhibited by 88% and 35%, respectively, after 24 h. A gradual recovery was observed after 48 and 72 h. With a higher dose (50 mg kg−1), the birds died, or were killed 3 h after dosing. Serum BChE and brain acetylcholinesterase (AChE), in birds that were sampled at 3 h, were inhibited by 98% and 92%, respectively. Hepatic microsomal and serum CEs were also inhibited. There was a statistically significant correlation (r=0.9808, p<0.001) between the activities of serum BChE and brain AChE. Swallows (Hirundo rustica) nesting in a stable treated with azamethiphos showed a drastic reduction in BChE (56%) and CE (36%) 24 h after treatment of the stable.

Evaluation of toxic effects of the organophosphorus insecticide azinphos-methyl in experimentally and naturally exposed birds

Laboratory and field studies were conducted to evaluate the effects of the organophosphorus insecticide, azinphosmethyl, on bird populations and into the possibility of assessing toxic hazard by a non-destructive biomarker such as BChE inhibition. Japanese quail were treated with increasing doses of azinphos-methyl (0.5, 5, and 50 mg/kg) and sacrificed 7 and 24 h later. Serum BChE and CbE, brain AChE, and liver microsomal CbE activities showed different patterns of inhibition. The maximum inhibition of BChE and CbE usually occurred 7 h after treatment, whereas the effect on AChE was greater at 24 h. A positive correlation was found between BChE and AChE, 7 and 24 h after treatment. This correlation could serve as the foundation for a theoretical model for assessing toxic hazard through non-destructive biomarkers. The only effect on brain AChE was detected in the group treated with the highest concentrations of azinphos-methyl (50 mg/kg). Fugacity model calculations showed that such massive concentrations are very unlikely to occur under natural conditions after agricultural use of the compound.The non-destructive biomarker was used to test a population of tree sparrows living in a cherry orchard sprayed once with azinphos-methyl. No inhibition of BChE activity was found 24 h after application, and it was therefore concluded that the concentration of the insecticide used did not constitute a hazard for the birds.

An assessment of pollutants in eggs of audouin's gull (Larus audouinii), a rare species of the Mediterranean sea

Audouins gull (Larus audouinii) is a very rare species endemic to the Mediterranean basin. A sub-population of an estimated 130 pairs is breeding in the Tuscan Archipelago, an area heavily polluted by mercury and chlorinated hydrocarbons. Here we present the data from 5 years spent monitoring the contaminant levels in the eggs of this species. Mercury, selenium, polychlorobiphenyls (PCBs) and DDE concentrations are two to five times higher than in similar species, such as the yellow-legged herring gull, nesting in the same area. The annual trends in these contaminant levels are discussed. In view of the endangered status of Audouins gull, there is a need to observe closely the developing trend of contamination in this species.

Interspecific differences in mixed function oxidase activity in birds: a tool to identify ‘species at risk’

Abstract The aim of this study was to explore the influence of diet on the development of interspecific differences in the detoxication capacity of the mixed function oxidase (MFO) system (monooxygenase) among birds. The role of MFO activity in the detoxication/bioaccumulation of organochlorines (e.g., PCBs) was also investigated. Seven different species of birds were analysed: the yellow-legged herring gull ( Larus cachinnans ), black-headed gull ( Larus ridibundus ), jackdaw ( Corvus monedula ), magpie ( Pica pica ), cormorant, ( Phalacrocorax carbo ), coot ( Fulica atra ) and sparrow ( Passer italiae ). These species have different feeding habits ranging from omnivorous species like the yellow-legged herring gull to specialist and stenophagic species like the cormorant. This preliminary study confirms the relationship between feeding habits and evolutionary interspecific diffences in MFO activity.