Cleft Palate Syndrome in the Endangered Spectacled Flying Fox (Pteropus conspicillatus): Implications for Conservation and Comparative Research

Cleft palate syndrome, first observed in the spectacled flying fox population in 1998, has produced sporadic neonatal mortality events over the past two decades, with an estimated incidence of up to 1/1000 births per year. This study presents a rudimentary characterisation of the syndrome, presenting gross pathology of syndromic signs upon visual inspection, a histological examination of palate malformations, and syndrome incidence data representing the past two decades. The syndrome presents with a range of signs, primarily congenital palate malformations ranging from a pinhole cleft to a complete hard and soft palate deficit, resulting in the death or abandonment of neonates shortly after birth. The congenital palate malformations are often associated with claw deformities, wiry facial hair, and in some instances, muscle weakness and neurological signs. The natural occurrence of the lethal congenital orofacial birth defects in the spectacled flying fox presents a unique opportunity for the investigation of putative aetiologies, drawing parallels between bat and other mammalian cleft palate risk factors. Further syndrome investigation has the potential to deliver both biodiversity conservation and comparative veterinary and biomedical outcomes.

Poisonous plants: effects on embryo and fetal development

Poisonous plant research in the United States began over 100 years ago as a result of livestock losses from toxic plants as settlers migrated westward with their flocks, herds, and families. Major losses were soon associated with poisonous plants, such as locoweeds, selenium accumulating plants, poison-hemlock, larkspurs, Veratrum, lupines, death camas, water hemlock, and others. Identification of plants associated with poisoning, chemistry of the plants, physiological effects, pathology, diagnosis, and prognosis, why animals eat the plants, and grazing management to mitigate losses became the overarching mission of the current Poisonous Plant Research Laboratory. Additionally, spin-off benefits resulting from the animal research have provided novel compounds, new techniques, and animal models to study human health conditions (biomedical research). The Poisonous Plant Research Laboratory has become an international leader of poisonous plant research as evidenced by the recent completion of the ninth International Symposium on Poisonous Plant Research held July 2013 in Hohhot, Inner Mongolia, China. In this article, we review plants that negatively impact embryo/fetal and neonatal growth and development, with emphasis on those plants that cause birth defects. Although this article focuses on the general aspects of selected groups of plants and their effects on the developing offspring, a companion paper in this volume reviews current understanding of the physiological, biochemical, and molecular mechanisms of toxicoses and teratogenesis.

Piperidine alkaloids: human and food animal teratogens

Piperidine alkaloids are acutely toxic to adult livestock species and produce musculoskeletal deformities in neonatal animals. These teratogenic effects include multiple congenital contracture (MCC) deformities and cleft palate in cattle, pigs, sheep, and goats. Poisonous plants containing teratogenic piperidine alkaloids include poison hemlock (Conium maculatum), lupine (Lupinus spp.), and tobacco (Nicotiana tabacum) [including wild tree tobacco (Nicotiana glauca)]. There is abundant epidemiological evidence in humans that link maternal tobacco use with a high incidence of oral clefting in newborns; this association may be partly attributable to the presence of piperidine alkaloids in tobacco products. In this review, we summarize the evidence for piperidine alkaloids that act as teratogens in livestock, piperidine alkaloid structure-activity relationships and their potential implications for human health.

The effect of body condition on serum concentrations of two teratogenic alkaloids (anagyrine and ammodendrine) from lupines (Lupinus species) that cause crooked calf disease

Several species of lupine (Lupinus spp.) are toxic to livestock, causing death losses in sheep and cattle but more commonly crooked calf disease in pregnant range cows. The major toxic alkaloids in lupine are of the quinolizidine alkaloid group and include the teratogen anagyrine, which is primarily responsible for crooked calf disease. Lupines also contain teratogenic piperidine alkaloids including ammodendrine. Previous work in sheep has shown that lupine alkaloid clearance may be influenced by the animal's physiological status. Therefore, the purpose of this study was to determine if differences in body condition of cattle would alter the absorption and elimination of anagyrine or ammodendrine given in a single oral dose as Lupinus leucophyllus or Lupinus sulphureus, respectively. Mature non-lactating cows in low body condition (LBC, n = 4) and high body condition (HBC, n = 4) received a single dose of dry ground lupine plant (2.0 g/kg of BW) via oral gavage. Lupinus leucophyllus (anagyrine) was dosed first; then after 21 d the same animals were dosed with L. sulphureus (ammodendrine). Blood samples were taken via jugular venipuncture 0 to 60 h after dosing. Serum anagyrine and ammodendrine concentrations were evaluated. The concentration of anagyrine was greater (P = 0.001) in the HBC group and peaked 2 h after dosing versus 12 h in LBC cows. Similarly for ammodendrine, the alkaloid concentration peaked at 3 h after dosing for the HBC group compared with 6 h for the LBC group (P = 0.001). Area under the curve tended to differ (P <or= 0.11) for both alkaloids in the HBC group compared with the LBC group. There were also differences in the maximum serum anagyrine (P = 0.02) and ammodendrine (P = 0.06) concentrations. Elimination half-life (E1/2) tended to differ (P = 0.12) between the HBC and LBC groups for ammodendrine. The kinetic profiles suggest that body condition influenced the disposition of these alkaloids. This study also suggests that body condition may impact the risk of toxicity, teratogenicity, or both of these alkaloids.

How do predators cope with chemically defended foods?

Many prey species (including plants) deter predators with defensive chemicals. These defensive chemicals act by rendering the prey's tissues noxious, toxic, or both. Here, I explore how predators cope with the presence of these chemicals in their diet. First, I describe the chemosensory mechanisms by which predators (including herbivores) detect defensive chemicals. Second, I review the mechanisms by which predators either avoid or tolerate defensive chemicals in prey. Third, I examine how effectively free-ranging predators can overcome the chemical defenses of prey. The available evidence indicates that predators have mixed success overcoming these defenses. This conclusion is based on reports of free-ranging predators rejecting unpalatable but harmless prey, or voluntarily ingesting toxic prey.

Effects of short-term early gestational exposure to endophyte-infected tall fescue diets on plasma 3,4-dihydroxyphenyl acetic acid and fetal development in mares

Consumption of wild-type (toxic) endophyte-infected tall fescue (E+) by horses during late gestation is known to adversely affect pregnancy outcome; however, little is known of the potential disruptive consequences of E+ consumption by mares during the critical phases of placentation and fetal development in early pregnancy. The objective of this study was to evaluate the detrimental effects of feeding E+ to mares during early gestation. Mares (n = 12) paired by stage of gestation (d 65 to 100) were assigned to diets (six per diet) consisting of endophyte-free (E-) or E+ tall fescue seed (50% E- or E+ tall fescue seed, 45% sweet feed, and 10% molasses fed at 1.0% of BW/d). Mares also had ad libitum access to E+ or E- annual ryegrass hay, and were fed diets for 10 d. Following removal from the tall fescue diet on d 11, mares were placed on common bermudagrass pasture and monitored until d 21. Morning and evening rectal temperatures were recorded and daily blood samples were collected for progesterone and prolactin (PRL) analyses, whereas samples for 3,4-dihydroxyphenyl acetic acid (a catecholamine metabolite) analysis were collected on alternate days. For clinical chemistry analysis, blood samples were collected on d 0, 5, 10 and 21. Daily urine samples were collected for ergot alkaloid analysis, and ultrasonography was performed for presence of echogenic material in fetal fluids. Rectal temperatures (E+ 37.76+/-0.03; E- 37.84+/-0.03 degrees C) and serum PRL concentrations (E+ 14.06< or =0.76; E- 12.11+/-0.76 ng/mL) did not differ (P = 0.96) between treatments. Measuring the change in basal serum concentration from d 0 over time, progesterone concentrations did not differ (-0.64 +/-1.49 and -0.55+/-1.47 ng/mL for E+ and E- mares, respectively). There was no negative pregnancy outcome, and ultrasonography indicated no increase in echogenic material in fetal fluids. Plasma 3,4-dihydroxyphenyl acetic acid concentrations decreased (P < 0.05) in E+ compared with E- mares (2.1+/-0.14 and 4.4+/0.43 ng/mL, respectively). Urinary ergot alkaloid concentration was greater (P < 0.01) in mares consuming E+ compared with E- (532.12+/- 52.51 and 13.36+/-2.67 ng/mg of creatinine, respectively). Although no fetal loss was observed during the current study, elevated concentrations of urinary ergot alkaloid were consistent with depressed endogenous catecholamine activity, suggestive of an endocrine disruptive effect of hypothalamic origin.

Feed and forage toxicants affecting embryo survival and fetal development

Early embryonic and fetal development in mammals is sensitive to deficiencies and excesses of specific nutrients and toxicants. Operating directly and/or indirectly, these deficiencies and excesses can result in embryonic death or, in less severe circumstances, disruption of normal embryo and fetal growth. This paper explores the threats posed by feed and forage toxicants to the developing embryo and their impact on early programming of fetal development. Using significant examples, we consider the relevance of temporal sensitivities during early development in utero, and their implications for the morphology and functional competence of specific organs and tissues.

Biochemistry of hemlock (Conium maculatum L.) alkaloids and their acute and chronic toxicity in livestock. A review

The literature on Conium maculatum biochemistry and toxicology, dispersed in a large number of scientific publications, has been put together in this review. C. maculatum is a weed known almost worldwide by its toxicity to many domestic animals and to human beings. It is an Umbelliferae, characterized by long, hollow stems, reaching up to 2 m height at maturity, producing a large amount of lush foliage during its vegetative growth. Its flowers are white, grouped in umbels formed by numerous umbellules. It produces a large number of seeds that allow the plant to form thick stands in modified soils, sometimes encroaching on cultivated fields, to the extent of impeding the growth of any other vegetation inside the C. maculatum area of growth. Eight piperidinic alkaloids have been identified in this species. Two of them, gamma-coniceine and coniine are generally the most abundant and they account for most of the plant acute and chronic toxicity. These alkaloids are synthesized by the plant from eight acetate units from the metabolic pool, forming a polyketoacid which cyclises through an aminotransferase and forms gamma-coniceine as the parent alkaloid via reduction by a NADPH-dependent reductase. The acute toxicity is observed when animals ingest C. maculatum vegetative and flowering plants and seeds. In a short time the alkaloids produce a neuromuscular blockage conducive to death when the respiratory muscles are affected. The chronic toxicity affects only pregnant animals. When they are poisoned by C. maculatum during the fetuses organ formation period, the offspring is born with malformations, mainly palatoschisis and multiple congenital contractures (MCC; frequently described as arthrogryposis). Acute toxicity, if not lethal, may resolve in the spontaneous recovery of the affected animals provided further exposure to C. maculatum is avoided. It has been observed that poisoned animals tend to return to feed on this plant. Chronic toxicity is irreversible and although MCC can be surgically corrected in some cases, most of the malformed animals are lost. Since no specific antidote is available, prevention is the only way to deal with the production loses caused by this weed. Control with herbicides and grazing with less susceptible animals (such as sheep) have been suggested. C. maculatum alkaloids can be transferred to milk and to fowl muscle tissue through which the former can reach the human food chain. The losses produced by C. maculatum chronic toxicity may be largely underestimated, at least in some regions, because of the difficulty in associate malformations in offspring with the much earlier maternal poisoning.