Toxicity of thornapple (Datura stramonium L) seeds to the pig

Intra- and inter-laboratory validation of a dipstick immunoassay for the detection of tropane alkaloids hyoscyamine and scopolamine in animal feed

Tropane alkaloids (TAs) are toxic secondary metabolites produced by plants of, inter alia, the genera Datura (thorn apple) and Atropa (deadly nightshade). The most relevant TAs are (-)-L-hyoscyamine and (-)-L-scopolamine, which act as antagonists of acetylcholine muscarinic receptors and can induce a variety of distinct toxic syndromes in mammals (anti-cholinergic poisoning). The European Union has regulated the presence of seeds of Datura sp. in animal feeds, specifying that the content should not exceed 1000 mg kg(-1) (Directive 2002/32/EC). For materials that have not been ground, visual screening methods are often used to comply with these regulations, but these cannot be used for ground materials and compound feeds. Immunological assays, preferably in dipstick format, can be a simple and cost-effective approach to monitor feedstuffs in an HACCP setting in control laboratories. So far no reports have been published on immunoassays that are capable of detecting both hyoscyamine and scopolamine with equal sensitivity and that can be used, preferably in dipstick format, for application as a fast screening tool in feed analysis. This study presents the results obtained for the in-house and inter-laboratory validation of a dipstick immunoassay for the detection of hyoscyamine and scopolamine in animal feed. The target level was set at 800 µg kg(-1) for the sum of both alkaloids. By using a representative set of compound feeds during validation and a robust study design, a reliable impression of the relevant characteristics of the assay could be obtained. The dipstick test displayed similar sensitivity towards the two alkaloids and it could be concluded that the test has a very low probability of producing a false-positive result at blank level or a false-negative result at target level. The assay can be used for monitoring of TAs in feedstuffs, but has also potential as a quick screening tool in food- or feed-related poisonings.

Scopolamine in racing horses: trace identifications associated with dietary or environmental exposure

Scopolamine (L-hyoscine) identifications, often in small-number clusters, have been reported worldwide in performance horses over the last 30 years. Scopolamine is an Association of Racing Commissioners International (ARCI) class 3, penalty class B, substance with potential to affect performance. As such, scopolamine identification(s) in race or performance horses can result in significant penalties for the connections of the horse(s). Reviewed here is the worldwide distribution of scopolamine containing plants (primarily Datura spp.), with estimates of their potential toxicity to horses through dietary and/or environmental exposure. Also reviewed are the basic pharmacology of scopolamine and its precursor, urinary concentrations following feedstuff exposure, and the probable pharmacological/forensic significance of such findings. Based on an overview of the world literature on scopolamine, the expected characteristics of inadvertent environmental exposure are also presented with a view to making clear the potential of scopolamine identifications, with or without atropine, as a direct and expected outcome of both the worldwide distribution of scopolamine-containing plants and the sensitivity of modern equine drug testing. It is of particular interest that only 2/30 reported post-event equine identifications of scopolamine have been associated with atropine, suggesting that failure to identify atropine is not a biomarker of pharmaceutical administration of scopolamine. Available quantitative information associated with scopolamine identifications is consistent with the 75 ng/mL regulatory threshold for scopolamine currently used in Louisiana racing in the USA and the 30 ng/mL reporting threshold in effect in European racing.

Anti-nutritional factors of Datura in feedstuffs

Soybean seed, linseed, some cereals seeds, and their by-products are infected by Datura seed weed of different varieties. The most common Datura spp. noxious to the farm animals are D. stramonium (atropine alkaloid) and D. ferox (scopolamine, 98-100% of total alkaloids) mainly present in Europe and South America, respectively. The presence of alkaloids from Datura seeds in feedingstuffs may be responsible for chronic and/or subclinical toxic effects; acute poisoning from Datura seeds are rare. Pigs are the most sensitive animals to Datura poisoning, followed by cattle, horses, and chickens. Sheep and rabbits are indifferent to atropine presence in food because they synthesize the atropine esterase enzyme. The progressive atropine poisoning in pigs leads to a reduction of feed intake and growth, gastrointestinal motility and secretory activity, extreme mouth dryness, increased respiration and cardiac rate, pupil dilation, etc. Clinical symptoms are partly similar among different species. Toxic effects from Datura alkaloids presence in feeds showed possible variability of alkaloids content tolerated by pigs. In our recent trials, the threshold limit in pigs (20-60 kg live weight) was 1.5 mg alkaloids/kg of feed (1.21 mg alkaloids/kg l.w.75).

Toxicity study of the main alkaloids of Datura ferox in broilers

Seeds of the weed Datura ferox are frequent contaminants of raw materials used for animal feed. These seeds produce various toxic effects and contain mainly the alkaloids scopolamine and hyoscyamine. In this 3-month toxicity study, a mixture of scopolamine and hyoscyamine (98:2) was incorporated at four total alkaloid levels (1.5, 15, 75 or 150 mg/kg feed) into a control diet fed to 100 broilers. Alkaloid feeding caused significant reductions in the body weight gain of birds, especially of those fed a dose of 150 mg alkaloid/kg feed. Growth-retarding effects, however, were transient, as no changes in body weight gain were noted after 52 days of alkaloid feeding. Alkaloid-treated broilers showed no significant differences from controls with respect to the cardiac rate and breathing frequency nor in relation to plasma aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase activities. In contrast, plasma leucine aminopeptidase activity was significantly reduced after 3 months in all alkaloid-fed birds. Autopsy and histological examination of tissues by light and electron microscopy revealed no pathological changes associated with alkaloid feeding. Broilers appeared generally healthy and behaved normally throughout. These data should be considered in the formulation of new, improved regulations defining the maximum allowable alkaloid content of D. ferox seeds contaminating raw materials destined for use as broiler feed.

Toxicological evaluation of jimson weed (Datura stramonium) seed

Diets containing 0.5, 1.58 and 5.0% jimson weed seed were fed to male and female rats (20/group) in a 90-day subchronic feeding study. The alkaloid content was 2.71 mg atropine and 0.66 mg scopolamine/g of seed. Gross clinical observations, body weights and feed and water intakes were recorded weekly. Tear production and pupil dilation measurements were made throughout the study. At 90 days, all of the animals were autopsied and clinical-chemistry analyses, complete haematology and bone-marrow evaluation for evidence of clastogenic effects were performed. Tissues from control (0% seed) and high-dose animals were examined histologically. The principal effects of jimson weed seed were: decreased body-weight gain, serum albumin and serum calcium; increased liver and testes weights (as a percentage of body weight), serum alkaline phosphatase and blood urea nitrogen. Female rats showed more marked responses to jimson weed seed than did males. In addition to the effects seen in both sexes, the females developed decreased serum total protein and cholesterol, and increased serum glutamic-pyruvic transaminase and chloride, red blood cell count, haemoglobin concentration and packed red cell volume. No histological lesions were associated with ingestion of jimson weed seed at 5.0%. It is concluded that jimson weed seed at concentrations of 0.5% or more in the diet produced adverse physiological changes in rats.