Metoclopramide protection of diazinon-induced toxicosis in chickens

The efficacy of metoclopramide for preventing organophosphate insecticide-induced (diazinon) toxicosis was evaluated in 7~14 days old chicks. Injection of metoclopramide at 25 mg/kg, s.c. 15 min before diazinon increased the oral 24 h median lethal dose of the insecticide in the chicks by 80%. Metoclopramide alone inhibited the in vitro and in vivo plasma and whole brain cholinesterase activities of the chicks. Metoclopramide pretreatment at 100 mg/kg, s.c. reduced the extent of cholinesterase inhibition that was caused by diazinon (10 mg/kg, p.o.) in the plasma and whole brain by 24% and 7%, respectively. Diazinon at 10 mg/kg, p.o. produced signs of cholinergic toxicosis in the chicks, and these signs included salivation, lacrimation, gasping and convulsions within 2 h, and the 2-h and 24-h lethalities were 88 and 100%, respectively. Metoclopramide at the dose rates of 12.5, 25, 50, 100 and 200 mg/kg, s.c. given 15 min before diazinon (10 mg/kg, p.o.) variably decreased the occurrence of toxic manifestations in the chicks. The highest dose of metoclopramide (200 mg/kg, s.c.) reduced the 2-h and 24-h lethality of diazinon to 75% each and it reduced the overall toxicity score of diazinon by 32%. The data suggest that metoclopramide pretreatment only partially protected chicks against the acute toxicity of diazinon

Akutna oralna toksičnost organofosfornih insekticida i inhibicija kolinesteraza u pilića

Acute toxic effects of three commonly used insecticidal preparations of the organophosphates chlorpyrifos, diazinon, and dichlorvos were examined in mixed breed broiler chicks, and cholinesterase activity in plasma and brain were measured. The acute (24 h) oral median lethal doses (LD50) of chlorpyrifos, diazinon, and dichlorvos were 10.79 mg kg-1, 6.32 mg kg-1, and 6.30 mg kg-1, respectively, as determined by the up-and-down method in chicks. Signs of cholinergic toxicosis in the chicks appeared within two hours after dosing, and they included salivation, lacrimation, gasping, frequent defecation, drooping of wings, tremors, convulsions, and recumbency before death. Halving the oral LD50 of chlorpyrifos (5 mg kg-1), diazinon (3 mg kg-1), and dichlorvos (3 mg kg-1) caused immobility and wing drooping, but not the clinical signs of cholinergic toxicity. However, at full LD50 doses of these insecticides, chicks showed clinical signs of cholinergic toxicity similar to those seen in the LD50 experiments. Two out of six chicks died within two hours after treatment with LD50 doses of chlorpyrifos and dichlorvos, whereas LD50 dosing with diazinon caused death in three out of six chicks. Compared to control values, the insecticides reduced plasma and whole brain cholinesterase activities by 29 % to 84 % and 18 % to 77 %, respectively, depending on the dose. The decrease in plasma cholinesterase correlated well (r = 0.82) with that of the brain. These data suggest that organophosphate insecticides administered orally at LD50 doses induce clinical signs of cholinergic poisoning and concurrently reduce brain and plasma cholinesterase activities in chicks.Ispitano je akutno toksično djelovanje triju često rabljenih organofosfornih insekticida klorpirifosa, diazinona i diklorvosa u brojlera te je izmjerena aktivnost kolinesteraza u njihovoj plazmi i mozgu. Srednja letalna doza LD50 klorpirifosa iznosila je 10,79 mg kg-1, diazinona 6,32 mg kg-1 te diklorvosa 6,30 mg kg-1. Prvi su se znakovi kolinergičkoga sindroma u pilića javili unutar dva sata od oralne primjene, a obuhvaćali su slinjenje, suženje, teško disanje, učestalu defekaciju, obješena krila, drhtavicu, grčenje i nesposobnost stajanja uoči smrti. Oralna primjena polovice srednje letalne doze insekticida klorpirifosa (5 mg kg-1), diazinona (3 mg kg-1) i diklorvosa (3 mg kg-1) dovela je do nepokretnosti i obješenih krila, ali bez kliničkih znakova kolinergičke toksičnosti koji su uočeni kod pokusa radi utvrđivanja srednje letalne doze (LD50). Međutim, doze ovih insekticida koje su odgovarale LD50, dovele su do kliničkih znakova kolinergičke toksičnosti sličnih onima zamijećenim kod utvrđivanja LD50. Dva od šest pilića uginula su unutar dva sata od primjene bilo klorpirifosa bilo diklorvosa u dozama koje su odgovarale LD50, dok je diazinon u odgovarajućoj srednjoj letalnoj dozi uzrokovao smrt triju od šest pilića. U odnosu na kontrolne vrijednosti, insekticidi su doveli do smanjenja aktivnosti kolinesteraze koja je ovisila o dozi, a kretala se od 29 % do 84 % u plazmi te od 18 % do 77 % u mozgu. Pad aktivnosti kolinesteraze u plazmi dobro je korelirao s njezinim padom u mozgu (r=0,82). Ovi podaci upućuju na to da oralna primjena organofosfornih insekticida u dozama koje odgovaraju srednjoj letalnoj dozi dovode do znakova kolinergičkoga trovanja u pilića te do istodobnoga pada aktivnosti kolinesteraza u mozgu i plazmi

Akutna toksičnost veterinarskih i poljoprivrednih formulacija organofosfata diklorvosa i diazinona u pilića

Formulation components of organophosphate insecticidal preparations might affect their toxic action in animals. The objective of this study was to examine and compare the acute toxicity and cholinesterase inhibition in seven to 14-day-old chicks dosed orally with dichlorvos and diazinon in standard veterinary and agricultural formulations. The acute (24 h) oral median lethal doses (LD50) of the formulations were determined using the up-and-down method. Respective LD50 of dichlorvos of the veterinary and agricultural formulations in chicks were 11.1 mg kg-1 and 6.51 mg kg-1 and those of diazinon 6.4 mg kg-1 and 6.7 mg kg-1. Plasma and brain cholinesterase activities were measured by electrometry after in vivo and in vitro exposure to organophosphates. The chicks showed signs of cholinergic toxicosis within one hour of dosing. Dichlorvos (8 mg kg-1) and diazinon (4 mg kg-1) in the veterinary and agricultural formulation signifi cantly reduced both plasma and brain cholinesterase activities in the chicks. The veterinary formulation of dichlorvos reduced plasma ChE by 60 % and agricultural by 40 % and brain ChE by 93 % and 87 %, respectively. In contrast, ChE inhibition by diazinon in the agricultural formulation of diazinon was stronger than by the veterinary formulation; 72 % vs. 64 % in plasma and 97 % vs. 80 % in the brain, respectively. The highest in vitro inhibitions were observed with dichlorvos in the agricultural formulation (50 %) in the brain samples and with diazinon in the agricultural formulation (52 %) in the plasma samples. While they exist, differences between formulations cannot be taken as a rule and further investigations should inventory the toxicity of standard veterinary and agricultural organophosphate formulations in addition to the known data for pure forms.Sastojci formulacija mogu djelovati na toksičnost organofosfatnih insekticidnih pripravaka u životinja. Cilj je ovog istraživanja bio ispitati i usporediti akutnu inhibiciju kolinesteraza u pilića starih 7 do 14 dana koji su na usta primili organofosfatne insekticide diklorvos i diazinon u odgovarajućim formulacijama za veterinarsku odnosno poljoprivrednu primjenu. Dvadesetčetverosatna akutna letalna doza (LD50) diklorvosa bila je 11,1 mg kg-1 u veterinarskim odnosno 6,51 mg kg-1 u poljoprivrednim formulacijama, a diazinona 6,4 mg kg-1 odnosno 6,7 mg kg-1. Do kolinergičke toksikoze u pilića došlo je jedan sat nakon primjene. Nakon izlaganja organofosfatima in vivo i in vitro izmjerena je aktivnost kolinesteraza u plazmi i mozgu s pomoću elektrometrije. Oralne doze diklorvosa (8 mg kg-1) odnosno diazinona (4 mg kg-1) putem veterinarskih odnosno poljoprivrednih formulacija značajno su smanjile aktivnost kolinesteraza u plazmi i mozgu pilića. In vitro su također oba organofosfata inhibirala aktivnost kolinesteraza, bez obzira na formulaciju. Poljoprivredna formulacija diklorvosa izazvala je najjaču inhibiciju (50 %) u mozgu pilića, dok je poljoprivredna formulacija diazinona najjače inhibirala (52 %) aktivnost u plazmi. Ovo istraživanje pokazuje da različite formulacije organofosfatnih insekticida mogu dovesti do različita otrovanja i različito djelovati na kolinesteraznu aktivnost u mozgu i plazmi

Evaluation of ground reaction forces produced by chickens walking on a force plate

Objective: To evaluate the use of a force plate as a method for objective gait analysis in adult poultry, to characterize ground reaction forces (GRFs) produced in adult chickens during normal walking, and to assess the variability of GRFs. Animals: 18 clinically normal 5-month-old Brown Leghorn hens Procedure: Vertical, craniocaudal, and mediolateral GRFs were measured as hens walked across a stan-dard force plate embedded in the middle of a runway. Results: All GRFs were significantly affected by speed, and variability was high. With increasing speed, overall stance time decreased, but the per-centage of stance time spent in braking or propulsion remained approximately equal. There was an overall increase in maximum propulsion force, which was produced at a greater rate over a shorter time; thus, propulsion integral ecreased. Maximum braking forces and braking integrals were variable, but the rate at which the forces were generated increased. Mediolateral forces were 2 to 3 times greater in hens than values that have been reported for other species. Conclusions and Clinical Relevance: A standard force plate can be used to objectively measure GRFs in walking adult hens; however, the large variation in the data suggests that the technique in its current form would be of limited clinical use. Overall, vertical and craniocaudal forces had similar characteristics to those of other species, whereas mediolateral forces were found to be much greater in chickens than for other species