Phytotoxins eliminated by milk: a review

Abstract

Milk is a complex emulsion of lipids suspended in aqueous protein solution that can be a carrier of various contaminants, but generally it is not an important route of toxic excretion. The main problem is chronic repetitive exposure, as it occurs with ingestion of toxic plants and its potential danger to animals that consume the milk. Previously reported hazardous phytotoxins eliminated by milk include: indolizidine alkaloids, causing oligosaccharide storage disease; piperidine alkaloids, causing acute poisoning or malformations; pyrrolizidine alkaloids, which cause hepatic lesions; quinolizidine alkaloids, as a cause of skeletal defects; glucosinolates, which cause changes in the thyroid; tremetol (or tremetone), which causes a disease characterized by tremors in animals and milk sickness in humans; sodium monofluoracetate, which causes the death of kids after ingestion of colostrum from goats that have ingested Amorimia septentrionalis during gestation; ptaquiloside, which induces carcinogenesis in animals that ingest milk or derivatives produced by animals that have ingested Pteridium spp. Ipomoea asarifolia, which contains indole diterpenes causing tremors in suckling pups. Chrysocoma ciliata causes alopecia in suckling pups, but its toxic compound is still unknown. Knowledge about the risk of exposure to these substances via milk and its dissemination are important for veterinary and human health.

Tremorgenic syndrome in suckling lambs due to poisoning by Ipomoea asarifolia

“…The components that cause tremorgenic syndrome associated with the consumption of I. asarifolia are indolediterpenes produced by the symbiotic fungi Clavicipitaceous and Periglandula (8,11,18,19). Some of the pure compounds belonging to this class have demonstrated a tremorgenic effect on mice (6,19) there is no specific treatment for the neutralization of tremorgenic toxins, the recommendation is to remove affected animals from areas invaded by the plant, since sheep can fully recover from seven to 21 days after the onset of the first clinical signs (2).…”

“…The ginger-leaf morning glory, Ipomoea asarifolia (Convolvulaceae), is an herbaceous plant with cordate base leaves and purplish pink flowers (1). It is widely distributed in the north and northeast Brazil (4,11), especially close to rivers and lakes with highly saline soil (4,16). When found in grazing areas of ruminants, it can cause outbreaks of poisoning, especially during prolonged dry seasons when there is shortage of forage (2,11).…”

“…It is widely distributed in the north and northeast Brazil (4,11), especially close to rivers and lakes with highly saline soil (4,16). When found in grazing areas of ruminants, it can cause outbreaks of poisoning, especially during prolonged dry seasons when there is shortage of forage (2,11). I. asarifolia belongs to the group of tremorgenic plants and its ingestion causes a syndrome characterized by tremors (6,8).…”

“…It is an important toxic plant in northeastern Brazils' affecting the central nervous system of ruminants (16). Outbreaks mainly occur in sheep, especially young animals, but goats, cattle and buffaloes may also be affected (1,4,11,16). Experimental poisoning has been demonstrated in sheep, goats, cattle, buffaloes and rodents (2,6,17,19).…”

“…Tremors over the entire body, especially the head and neck are the most evident clinical sign in poisoned sheep, which intensify when the animals are stimulated to move (13). Affected ruminants may suffer falls in unusual positions, followed by pedaling movements and difficulty returning to the upright position (11,12). At rest, the main clinical signs are staggering gait, wide-based stance and ataxia (3,5).…”