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Cyanogenic glycosides, which release cyanide, are present in several plant species of high importance for animal production, such as cassava and sorghum. Several human neurological diseases have been associated with chronic cyanide exposure. On the other hand, these effects in ruminants are almost unknown. Thus, the objective of the present study was to determine the long-term lesions of the central nervous system (CNS) caused by daily administration of potassium cyanide (KCN) to goats. Thirty-four male goats were divided into five groups, respectively treated orally with 0 (control), 0.3, 0.6, 1.2 or 3.0 mg KCN/kg/day for 5 months. At the end of the experiment, the whole CNS of each animal was collected for histopathology and immunohistochemistry for apoptotic markers (BAX, BCl2 and CPP32) and for glial fibrillary acid protein (GFAP; vimentin). The results showed the presence of spheroids in the pons, medulla oblongata, and ventral horn of the spinal cord, gliosis and spongiosis in medulla oblongata, gliosis in the pons, and damaged Purkinje cells in the cerebellum from goats that received the higher cyanide dose. In goats from the 1.2 mg KCN/kg group we observed congestion and hemorrhage in the cerebellum, and spheroids in the spinal cord. Gliosis was confirmed by GFAP protein expression. Immunohistochemistry for apoptotic markers and typical apoptotic morphology suggested apoptosis did not participate in the pathogenesis of the observed lesions. Thus, chronic cyanide exposure can promote neurophatological lesions also in goats, and this species can be a useful ruminant model to study the neurotoxic effects of long-term cyanide exposure. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to determine if sheep could be averted to Mascagnia rigida, a toxic plant found in the semiarid region of northeastern Brazil. Twelve female sheep naïve to M. rigida were randomly allocated to two treatment groups: control (treated with 15mL water orally by a drenching gun) and lithium group (treated with 150mg LiCl/kg body weight orally by a drenching gun). For conditioning, sheep were allowed to feed on M. rigida leaves for 15min, followed by LiCl or water administration. The time spent eating M. rigida leaves was measured. The conditioning was repeated daily until the LiCl-treated sheep stopped eating M. rigida, which occurred at days 2 and 3. Persistence trials were conducted on day 10, 24, 40, 55, and 70 of the trial using single-choice tests. There was no difference between the two treatment groups with respect to the consumption of M. rigida on the first day of aversion conditioning. On the second day, three out of the six sheep in the lithium group did not eat the leaves, but on the third day, all the sheep in the lithium group did not ingest M. rigida. This aversion persisted throughout all the persistence trials. This indicates that sheep can be easily conditioned by using lithium chloride to avoid eating M. rigida. [Copyright &y& Elsevier]

Abstract: Here, we aimed to determine the toxicity of Cryptostegia venusta in goats and rats. We orally administered a single 60g dose of shredded C. venusta leaves per kilogram of body weight to three goats. The animals were necropsied after death, and tissue sections were collected and routinely processed for histopathological analyses. Additionally, we separated 25 adult male Wistar rats (each weighing about 150g) into five groups: an untreated control group and groups orally treated with 1, 3, 10, or 60g/kg doses. Rats were sacrificed 72h after administration of the C. venusta extract, and tissue sections collected for histopathological analyses. All goats presented signs of apathy, salivation, frequent urination, and eventually fatigue 4–6h after receiving C. venusta. Two goats died 20h after administration, and the third was sacrificed in extremis. The only histopathological finding observed in the goats was lung edema. No rats died during the experimental period or presented any clinical signs or macroscopic lesions. However, both goats and rats exhibited degeneration and multifocal necrosis of cardiac muscle fibers. From our results, we conclude that the C. venusta plant is capable of promoting cardiotoxicity. [Copyright &y& Elsevier]

Abstract: Cases of poisoning by oleander (Nerium oleander) were observed in several species, except in goats. This study aimed to evaluate the pathological effects of oleander in goats. The experimental design used three goats per group: the control group, which did not receive oleander and the experimental group, which received leaves of oleander (50mg/kg/day) for six consecutive days. On the seventh day, goats received 110mg/kg of oleander leaves four times at one-hourly interval. A last dose of 330mg/kg of oleander leaves was given subsequently. After the last dose was administered, clinical signs such as apathy, colic, vocalizations, hyperpnea, polyuria, and moderate rumen distention were observed. Electrocardiogram revealed second-degree atrioventricular block. Death occurred on an average at 92min after the last dosing. Microscopic evaluation revealed renal necrosis at convoluted and collector tubules and slight myocardial degeneration was observed by unequal staining of cardiomyocytes. Data suggest that goats appear to respond to oleander poisoning in a manner similar to other species. [Copyright &y& Elsevier]